Re: [time-nuts] Brooks Shera
Some how time nuts combined two lines it is Karen Stoll46 Crazy Rabbit Rd Santa Fee, NM 87508 In a message dated 12/19/2012 3:55:33 P.M. Eastern Standard Time, ewkeh...@aol.com writes: Brooks Shera has been a major contributor with his GPSDO. Before Tbolts where affordable his QST article for the first time opened the door for many amateurs to precision frequency at an affordable price. Over the years I build many units. For a year I have tried to buy his latest version 4.02. I did not get a response, so last week I wrote a hardcopy letter. Yesterday I got an answer from his wife Karen Stoll. She is not able to access his emails. Brooks is in a Memory Care Unit in a local senior residence, suffering from dementia. I think it is appropriate that those of us that appreciate his contribution take the time to write a personal note to his wife, I am sure it will help her in these difficult times and maybe seeing the letters will help him to. Bert Kehren Karen Stoll46 Crazy Rabbit Rd. Santa Fe, NM 87508 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Bert Thank you for reaching out to Brook and his wife. I agree that the QST article that Brook wrote really did change the capabilities that Amateur time keepers and Radio Operators have access to. I am very sad to hear the reason why he has been un-responsive. Thanks again for sharing this sad news. Paul WB8TSL On Wed, Dec 19, 2012 at 4:03 PM, wrote: > Some how time nuts combined two lines it is > Karen Stoll46 Crazy Rabbit Rd Santa Fee, NM 87508 > > > In a message dated 12/19/2012 3:55:33 P.M. Eastern Standard Time, > ewkeh...@aol.com writes: > > > Brooks Shera has been a major contributor with his GPSDO. Before Tbolts > where affordable his QST article for the first time opened the door for > many > amateurs to precision frequency at an affordable price. Over the years I > build many units. For a year I have tried to buy his latest version 4.02. > I > did not get a response, so last week I wrote a hardcopy letter. > Yesterday I got an answer from his wife Karen Stoll. She is not able to > access his emails. > Brooks is in a Memory Care Unit in a local senior residence, suffering > from dementia. > I think it is appropriate that those of us that appreciate his > contribution take the time to write a personal note to his wife, I am > sure it will > help her in these difficult times and maybe seeing the letters will help > him > to. > Bert Kehren > Karen Stoll46 Crazy Rabbit Rd. > Santa Fe, NM 87508 > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
The 1998 Shera QST article was also my first reading about GPSDO. In 1999 we were using the Epsilon OEM board GPSDO from Temex for the first terrestrial DVB single frequency network trials. On Wed, Dec 19, 2012 at 10:33 PM, paul swed wrote: > Bert > Thank you for reaching out to Brook and his wife. I agree that the QST > article that Brook wrote really did change the capabilities that Amateur > time keepers and Radio Operators have access to. I am very sad to hear the > reason why he has been un-responsive. > Thanks again for sharing this sad news. > Paul > WB8TSL > > On Wed, Dec 19, 2012 at 4:03 PM, wrote: > > > Some how time nuts combined two lines it is > > Karen Stoll46 Crazy Rabbit Rd Santa Fee, NM 87508 > > > > > > In a message dated 12/19/2012 3:55:33 P.M. Eastern Standard Time, > > ewkeh...@aol.com writes: > > > > > > Brooks Shera has been a major contributor with his GPSDO. Before Tbolts > > where affordable his QST article for the first time opened the door for > > many > > amateurs to precision frequency at an affordable price. Over the years > I > > build many units. For a year I have tried to buy his latest version > 4.02. > > I > > did not get a response, so last week I wrote a hardcopy letter. > > Yesterday I got an answer from his wife Karen Stoll. She is not able to > > access his emails. > > Brooks is in a Memory Care Unit in a local senior residence, suffering > > from dementia. > > I think it is appropriate that those of us that appreciate his > > contribution take the time to write a personal note to his wife, I am > > sure it will > > help her in these difficult times and maybe seeing the letters will > help > > him > > to. > > Bert Kehren > > Karen Stoll46 Crazy Rabbit Rd. > > Santa Fe, NM 87508 > > ___ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > ___ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Bert A thought has crossed my mind here. His wife can not access his computer. If its windows XP or earlier the password is recoverable. I use a boot cd that exposes all. Its been helpful. Is there a way to reach out and offer help aside from snail mail? Would she be open to that help? Regards Paul On Wed, Dec 19, 2012 at 4:03 PM, wrote: > Some how time nuts combined two lines it is > Karen Stoll46 Crazy Rabbit Rd Santa Fee, NM 87508 > > > In a message dated 12/19/2012 3:55:33 P.M. Eastern Standard Time, > ewkeh...@aol.com writes: > > > Brooks Shera has been a major contributor with his GPSDO. Before Tbolts > where affordable his QST article for the first time opened the door for > many > amateurs to precision frequency at an affordable price. Over the years I > build many units. For a year I have tried to buy his latest version 4.02. > I > did not get a response, so last week I wrote a hardcopy letter. > Yesterday I got an answer from his wife Karen Stoll. She is not able to > access his emails. > Brooks is in a Memory Care Unit in a local senior residence, suffering > from dementia. > I think it is appropriate that those of us that appreciate his > contribution take the time to write a personal note to his wife, I am > sure it will > help her in these difficult times and maybe seeing the letters will help > him > to. > Bert Kehren > Karen Stoll46 Crazy Rabbit Rd. > Santa Fe, NM 87508 > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
He worked at LANL. Might be other stuff in there... On Fri, Dec 21, 2012 at 9:15 AM, paul swed wrote: > Bert > A thought has crossed my mind here. > His wife can not access his computer. > If its windows XP or earlier the password is recoverable. I use a boot cd > that exposes all. Its been helpful. > Is there a way to reach out and offer help aside from snail mail? > Would she be open to that help? > Regards > Paul > > On Wed, Dec 19, 2012 at 4:03 PM, wrote: > >> Some how time nuts combined two lines it is >> Karen Stoll46 Crazy Rabbit Rd Santa Fee, NM 87508 >> >> >> In a message dated 12/19/2012 3:55:33 P.M. Eastern Standard Time, >> ewkeh...@aol.com writes: >> >> >> Brooks Shera has been a major contributor with his GPSDO. Before Tbolts >> where affordable his QST article for the first time opened the door for >> many >> amateurs to precision frequency at an affordable price. Over the years I >> build many units. For a year I have tried to buy his latest version 4.02. >> I >> did not get a response, so last week I wrote a hardcopy letter. >> Yesterday I got an answer from his wife Karen Stoll. She is not able to >> access his emails. >> Brooks is in a Memory Care Unit in a local senior residence, suffering >> from dementia. >> I think it is appropriate that those of us that appreciate his >> contribution take the time to write a personal note to his wife, I am >> sure it will >> help her in these difficult times and maybe seeing the letters will help >> him >> to. >> Bert Kehren >> Karen Stoll46 Crazy Rabbit Rd. >> Santa Fe, NM 87508 >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
If needed, I can provide some local help. Karen's address is a short drive from my home. Kevin On Dec 21, 2012, at 7:15 AM, paul swed wrote: > Bert > A thought has crossed my mind here. > His wife can not access his computer. > If its windows XP or earlier the password is recoverable. I use a boot cd > that exposes all. Its been helpful. > Is there a way to reach out and offer help aside from snail mail? > Would she be open to that help? > Regards > Paul > > On Wed, Dec 19, 2012 at 4:03 PM, wrote: > >> Some how time nuts combined two lines it is >> Karen Stoll46 Crazy Rabbit Rd Santa Fee, NM 87508 >> >> >> In a message dated 12/19/2012 3:55:33 P.M. Eastern Standard Time, >> ewkeh...@aol.com writes: >> >> >> Brooks Shera has been a major contributor with his GPSDO. Before Tbolts >> where affordable his QST article for the first time opened the door for >> many >> amateurs to precision frequency at an affordable price. Over the years I >> build many units. For a year I have tried to buy his latest version 4.02. >> I >> did not get a response, so last week I wrote a hardcopy letter. >> Yesterday I got an answer from his wife Karen Stoll. She is not able to >> access his emails. >> Brooks is in a Memory Care Unit in a local senior residence, suffering >> from dementia. >> I think it is appropriate that those of us that appreciate his >> contribution take the time to write a personal note to his wife, I am >> sure it will >> help her in these difficult times and maybe seeing the letters will help >> him >> to. >> Bert Kehren >> Karen Stoll46 Crazy Rabbit Rd. >> Santa Fe, NM 87508 >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Ditto on that. I'm up in Los Alamos. Getting into computers is my specialty. -Bob On Fri, Dec 21, 2012 at 7:29 AM, Kevin Rosenberg wrote: > If needed, I can provide some local help. Karen's address is a > short drive from my home. > > Kevin > > On Dec 21, 2012, at 7:15 AM, paul swed wrote: > > > Bert > > A thought has crossed my mind here. > > His wife can not access his computer. > > If its windows XP or earlier the password is recoverable. I use a boot cd > > that exposes all. Its been helpful. > > Is there a way to reach out and offer help aside from snail mail? > > Would she be open to that help? > > Regards > > Paul > > > > On Wed, Dec 19, 2012 at 4:03 PM, wrote: > > > >> Some how time nuts combined two lines it is > >> Karen Stoll46 Crazy Rabbit Rd Santa Fee, NM 87508 > >> > >> > >> In a message dated 12/19/2012 3:55:33 P.M. Eastern Standard Time, > >> ewkeh...@aol.com writes: > >> > >> > >> Brooks Shera has been a major contributor with his GPSDO. Before > Tbolts > >> where affordable his QST article for the first time opened the door > for > >> many > >> amateurs to precision frequency at an affordable price. Over the > years I > >> build many units. For a year I have tried to buy his latest version > 4.02. > >> I > >> did not get a response, so last week I wrote a hardcopy letter. > >> Yesterday I got an answer from his wife Karen Stoll. She is not able > to > >> access his emails. > >> Brooks is in a Memory Care Unit in a local senior residence, suffering > >> from dementia. > >> I think it is appropriate that those of us that appreciate his > >> contribution take the time to write a personal note to his wife, I am > >> sure it will > >> help her in these difficult times and maybe seeing the letters will > help > >> him > >> to. > >> Bert Kehren > >> Karen Stoll46 Crazy Rabbit Rd. > >> Santa Fe, NM 87508 > >> ___ > >> time-nuts mailing list -- time-nuts@febo.com > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > >> ___ > >> time-nuts mailing list -- time-nuts@febo.com > >> To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >> and follow the instructions there. > >> > > ___ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
I will contact her and see mybe she may also need help to dispose of hardware and we can arrange a sale. Bert In a message dated 12/21/2012 9:15:56 A.M. Eastern Standard Time, paulsw...@gmail.com writes: Bert A thought has crossed my mind here. His wife can not access his computer. If its windows XP or earlier the password is recoverable. I use a boot cd that exposes all. Its been helpful. Is there a way to reach out and offer help aside from snail mail? Would she be open to that help? Regards Paul On Wed, Dec 19, 2012 at 4:03 PM, wrote: > Some how time nuts combined two lines it is > Karen Stoll46 Crazy Rabbit Rd Santa Fee, NM87508 > > > In a message dated 12/19/2012 3:55:33 P.M. Eastern Standard Time, > ewkeh...@aol.com writes: > > > Brooks Shera has been a major contributor with his GPSDO. Before Tbolts > where affordable his QST article for the first time opened the door for > many > amateurs to precision frequency at an affordable price. Over the years I > build many units. For a year I have tried to buy his latest version 4.02. > I > did not get a response, so last week I wrote a hardcopy letter. > Yesterday I got an answer from his wife Karen Stoll. She is not able to > access his emails. > Brooks is in a Memory Care Unit in a local senior residence, suffering > from dementia. > I think it is appropriate that those of us that appreciate his > contribution take the time to write a personal note to his wife, I am > sure it will > help her in these difficult times and maybe seeing the letters will help > him > to. > Bert Kehren > Karen Stoll46 Crazy Rabbit Rd. > Santa Fe, NM 87508 > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
I have send an email and will find out what help she would accept, but there is time when a snail mail is very powerful, and I again encourage all of you to take the time to write a snail mail note. Maybe he can still recognize it, but putting my self in Karen's place it will lighten her load and brighten her days. Bert In a message dated 12/21/2012 9:27:17 A.M. Eastern Standard Time, normanliz...@gmail.com writes: He worked at LANL. Might be other stuff in there... On Fri, Dec 21, 2012 at 9:15 AM, paul swed wrote: > Bert > A thought has crossed my mind here. > His wife can not access his computer. > If its windows XP or earlier the password is recoverable. I use a boot cd > that exposes all. Its been helpful. > Is there a way to reach out and offer help aside from snail mail? > Would she be open to that help? > Regards > Paul > > On Wed, Dec 19, 2012 at 4:03 PM, wrote: > >> Some how time nuts combined two lines it is >> Karen Stoll 46 Crazy Rabbit Rd Santa Fee, NM 87508 >> >> >> In a message dated 12/19/2012 3:55:33 P.M. Eastern Standard Time, >> ewkeh...@aol.com writes: >> >> >> Brooks Shera has been a major contributor with his GPSDO. Before Tbolts >> where affordable his QST article for the first time opened the door for >> many >> amateurs to precision frequency at an affordable price. Over the years I >> build many units. For a year I have tried to buy his latest version 4.02. >> I >> did not get a response, so last week I wrote a hardcopy letter. >> Yesterday I got an answer from his wife Karen Stoll. She is not able to >> access his emails. >> Brooks is in a Memory Care Unit in a local senior residence, suffering >> from dementia. >> I think it is appropriate that those of us that appreciate his >> contribution take the time to write a personal note to his wife, I am >> sure it will >> help her in these difficult times and maybe seeing the letters will help >> him >> to. >> Bert Kehren >> Karen Stoll46 Crazy Rabbit Rd. >> Santa Fe, NM 87508 >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
I just had this same problem, a computer owned by some one who had passed away. One dose not even need to know or recover the password. Simply remove the hard drive and place it on another computer and you will have access to all the files, copy over what is needed, re-format the drive, then put it back in the old PC and give the PC to the Goodwill store. If the user encrypted the disk, you are out of luck with out the key but you only typicaly see encryption with notebook computers used for business. I've seen this kind of dementia where the person needs full time care. By the time it goes that far the person does not know where they are or who anyone is. Many times they are upset and angry all the time because they can't figure out what's happening but other times they simply stair into space. I think whatthis says is that if you've worked hard to make a design available to others and you don't intend to sell it commercially, PUBLISH the details, the design files and the source code. Yes I kknow it is never "good enough" for others to see. But in reality it is likely better than what 99.9% of others can do. On Fri, Dec 21, 2012 at 6:15 AM, paul swed wrote: > Bert > A thought has crossed my mind here. > His wife can not access his computer. > If its windows XP or earlier the password is recoverable. I use a boot cd > that exposes all. Its been helpful. > Is there a way to reach out and offer help aside from snail mail? > Would she be open to that help? > Regards > Paul > > On Wed, Dec 19, 2012 at 4:03 PM, wrote: > >> Some how time nuts combined two lines it is >> Karen Stoll46 Crazy Rabbit Rd Santa Fee, NM 87508 >> >> >> In a message dated 12/19/2012 3:55:33 P.M. Eastern Standard Time, >> ewkeh...@aol.com writes: >> >> >> Brooks Shera has been a major contributor with his GPSDO. Before Tbolts >> where affordable his QST article for the first time opened the door for >> many >> amateurs to precision frequency at an affordable price. Over the years I >> build many units. For a year I have tried to buy his latest version 4.02. >> I >> did not get a response, so last week I wrote a hardcopy letter. >> Yesterday I got an answer from his wife Karen Stoll. She is not able to >> access his emails. >> Brooks is in a Memory Care Unit in a local senior residence, suffering >> from dementia. >> I think it is appropriate that those of us that appreciate his >> contribution take the time to write a personal note to his wife, I am >> sure it will >> help her in these difficult times and maybe seeing the letters will help >> him >> to. >> Bert Kehren >> Karen Stoll46 Crazy Rabbit Rd. >> Santa Fe, NM 87508 >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On 21 December 2012 18:11, Chris Albertson wrote: > I think whatthis says is that if you've worked hard to make a design > available to others and you don't intend to sell it commercially, > PUBLISH the details, the design files and the source code. Yes I > kknow it is never "good enough" for others to see. But in reality it > is likely better than what 99.9% of others can do. I agree if you don't want to sell it, then make it public, even if it is not "finished" That said, some of the code that people release, and gets circulated annoys me. Take a look at this unix shell script, http://boxen.math.washington.edu/home/kirkby/bad-code/sympow-1.018.1.p7/src/Configure or the C code in the same directory http://boxen.math.washington.edu/home/kirkby/bad-code/sympow-1.018.1.p7/src/ But another issue is that sometimes people DO want to make money from their code. In that case, they want to keep it secret (as Bruce did). But I supect in many cases they would probably agree to it being made public in the event of their death or them becoming incapacitated. Code like Bruch wrote is unlikely to be commerically useful to his family, so he might as well make it public. But it may be too late. I wonder if there is a technical solution to this. You encrypt your secret source code, giving the encrypted code to anyone that wants it. You give 3 people you trust part of the decryption key. Any two parts are sufficient to decrypt the code. Would something like that be acceptable to individuals that make money from code, but don't realistically believe it will survice commerically without them. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Kind of defocusing here. I think the thread is about possibly helping to release the shera v4.02 software. Several folks appear to be local to Brooks wife and may be able to help her recover information she may need in general and if we are lucky allow the software to be at least gathered. Regards Paul WB8TSL On Fri, Dec 21, 2012 at 3:30 PM, David Kirkby wrote: > On 21 December 2012 18:11, Chris Albertson > wrote: > > I think whatthis says is that if you've worked hard to make a design > > available to others and you don't intend to sell it commercially, > > PUBLISH the details, the design files and the source code. Yes I > > kknow it is never "good enough" for others to see. But in reality it > > is likely better than what 99.9% of others can do. > > I agree if you don't want to sell it, then make it public, even if it > is not "finished" > > That said, some of the code that people release, and gets > circulated annoys me. Take a look at this unix shell script, > > > http://boxen.math.washington.edu/home/kirkby/bad-code/sympow-1.018.1.p7/src/Configure > > or the C code in the same directory > > > http://boxen.math.washington.edu/home/kirkby/bad-code/sympow-1.018.1.p7/src/ > > > But another issue is that sometimes people DO want to make money from > their code. In that case, they want to keep it secret (as Bruce did). > But I supect in many cases they would probably agree to it being made > public in the event of their death or them becoming incapacitated. > Code like Bruch wrote is unlikely to be commerically useful to his > family, so he might as well make it public. But it may be too late. > > I wonder if there is a technical solution to this. You encrypt your > secret source code, giving the encrypted code to anyone that wants it. > You give 3 people you trust part of the decryption key. Any two parts > are sufficient to decrypt the code. Would something like that be > acceptable to individuals that make money from code, but don't > realistically believe it will survice commerically without them. > > > Dave > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
And folks, please respect Brooks' privacy -- remember that this list is archived in many places on the web. John paul swed said the following on 12/21/2012 04:06 PM: Kind of defocusing here. I think the thread is about possibly helping to release the shera v4.02 software. Several folks appear to be local to Brooks wife and may be able to help her recover information she may need in general and if we are lucky allow the software to be at least gathered. Regards Paul WB8TSL On Fri, Dec 21, 2012 at 3:30 PM, David Kirkby wrote: On 21 December 2012 18:11, Chris Albertson wrote: I think whatthis says is that if you've worked hard to make a design available to others and you don't intend to sell it commercially, PUBLISH the details, the design files and the source code. Yes I kknow it is never "good enough" for others to see. But in reality it is likely better than what 99.9% of others can do. I agree if you don't want to sell it, then make it public, even if it is not "finished" That said, some of the code that people release, and gets circulated annoys me. Take a look at this unix shell script, http://boxen.math.washington.edu/home/kirkby/bad-code/sympow-1.018.1.p7/src/Configure or the C code in the same directory http://boxen.math.washington.edu/home/kirkby/bad-code/sympow-1.018.1.p7/src/ But another issue is that sometimes people DO want to make money from their code. In that case, they want to keep it secret (as Bruce did). But I supect in many cases they would probably agree to it being made public in the event of their death or them becoming incapacitated. Code like Bruch wrote is unlikely to be commerically useful to his family, so he might as well make it public. But it may be too late. I wonder if there is a technical solution to this. You encrypt your secret source code, giving the encrypted code to anyone that wants it. You give 3 people you trust part of the decryption key. Any two parts are sufficient to decrypt the code. Would something like that be acceptable to individuals that make money from code, but don't realistically believe it will survice commerically without them. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
John I send my posting to Mrs. Stoll for approval prior to posting. Lets try not to start the usual arguments. Brooks deserves better. Bert Kehren In a message dated 12/21/2012 4:28:38 P.M. Eastern Standard Time, j...@febo.com writes: And folks, please respect Brooks' privacy -- remember that this list is archived in many places on the web. John paul swed said the following on 12/21/2012 04:06 PM: > Kind of defocusing here. I think the thread is about possibly helping to > release the shera v4.02 software. Several folks appear to be local to > Brooks wife and may be able to help her recover information she may need in > general and if we are lucky allow the software to be at least gathered. > Regards > Paul > WB8TSL > > On Fri, Dec 21, 2012 at 3:30 PM, David Kirkby wrote: > >> On 21 December 2012 18:11, Chris Albertson >> wrote: >>> I think whatthis says is that if you've worked hard to make a design >>> available to others and you don't intend to sell it commercially, >>> PUBLISH the details, the design files and the source code. Yes I >>> kknow it is never "good enough" for others to see. But in reality it >>> is likely better than what 99.9% of others can do. >> >> I agree if you don't want to sell it, then make it public, even if it >> is not "finished" >> >> That said, some of the code that people release, and gets >> circulated annoys me. Take a look at this unix shell script, >> >> >> http://boxen.math.washington.edu/home/kirkby/bad-code/sympow-1.018.1.p7/src/Configure >> >> or the C code in the same directory >> >> >> http://boxen.math.washington.edu/home/kirkby/bad-code/sympow-1.018.1.p7/src/ >> >> >> But another issue is that sometimes people DO want to make money from >> their code. In that case, they want to keep it secret (as Bruce did). >> But I supect in many cases they would probably agree to it being made >> public in the event of their death or them becoming incapacitated. >> Code like Bruch wrote is unlikely to be commerically useful to his >> family, so he might as well make it public. But it may be too late. >> >> I wonder if there is a technical solution to this. You encrypt your >> secret source code, giving the encrypted code to anyone that wants it. >> You give 3 people you trust part of the decryption key. Any two parts >> are sufficient to decrypt the code. Would something like that be >> acceptable to individuals that make money from code, but don't >> realistically believe it will survice commerically without them. >> >> >> Dave >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
In message , David Kirkby writes: >On 21 December 2012 18:11, Chris Albertson wrote: >That said, some of the code that people release, and gets >circulated annoys me. Take a look at this unix shell script, I wrote something about that for ACM: http://queue.acm.org/detail.cfm?id=2349257 -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Sad news. I wonder if his web pages will survive him. If not, the Internet Archive has archived the information. The latest is at: http://web.archive.org/web/20120823060601/http://www.rt66.com/~shera/ Joe Gray W5JG On Sat, Mar 23, 2013 at 1:48 PM, wrote: > Brooks Shera passed away last Saturday. There will be an obituary published > tomorrow in the Santa Fe New Mexican. It should also be available online. > As I have mentioned in the past I credit him with making available to time > nuts, radio amateurs and other hobbyists a method to obtain precise > frequency at an affordable price before commercial GPSDO's flooded the > market. > At the time I personally had ten cesium's thanks to the bankruptcy of > Offshore Navigation I started building disciplined Rb's with the help of > Brooks. > Eight and counting. > If there was a Hall of Fame for time nuts he would be # 1 on my list > Bert Kehren > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Bert, On 03/23/2013 08:48 PM, ewkeh...@aol.com wrote: Brooks Shera passed away last Saturday. There will be an obituary published tomorrow in the Santa Fe New Mexican. It should also be available online. As I have mentioned in the past I credit him with making available to time nuts, radio amateurs and other hobbyists a method to obtain precise frequency at an affordable price before commercial GPSDO's flooded the market. At the time I personally had ten cesium's thanks to the bankruptcy of Offshore Navigation I started building disciplined Rb's with the help of Brooks. Eight and counting. If there was a Hall of Fame for time nuts he would be # 1 on my list Sad to hear this news. His contribution to this field will be remembered. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On Sat, Mar 23, 2013 at 1:41 PM, Joseph Gray wrote: > Sad news. I wonder if his web pages will survive him. If not, the > Internet Archive has archived the information. The latest is at: > http://web.archive.org/web/20120823060601/http://www.rt66.com/~shera/ The webarchive seems to be complete except that there is no link to the assembly language source code. Only the hex file is available. The QST article said thew source was available but I don't think it is unless perhaps some one here has a copy. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Bert, Sorry to hear that. He was very kind to help me with my first 'Shera Board' with parts and helping to get it up and working with an HP 105B. I wrote a note to his wife a couple of months ago. I agree with your thoughts. He went out of his way to help a stranger and I appreciate it. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ewkeh...@aol.com Sent: Saturday, March 23, 2013 2:49 PM To: time-nuts@febo.com Cc: st...@rt66.com Subject: [time-nuts] Brooks Shera Brooks Shera passed away last Saturday. There will be an obituary published tomorrow in the Santa Fe New Mexican. It should also be available online. As I have mentioned in the past I credit him with making available to time nuts, radio amateurs and other hobbyists a method to obtain precise frequency at an affordable price before commercial GPSDO's flooded the market. At the time I personally had ten cesium's thanks to the bankruptcy of Offshore Navigation I started building disciplined Rb's with the help of Brooks. Eight and counting. If there was a Hall of Fame for time nuts he would be # 1 on my list Bert Kehren ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
I know someone at archive.org. I can probably get the website patched if someone can supply the missing files. I never built Brooks most accurate clock, but of course wanted to so. When I found some NOS symetricoms and got them going, the plug and play experience was kind of a let down. -Original Message- From: Chris Albertson Sender: time-nuts-boun...@febo.com Date: Sat, 23 Mar 2013 15:00:44 To: Discussion of precise time and frequency measurement Reply-To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Brooks Shera On Sat, Mar 23, 2013 at 1:41 PM, Joseph Gray wrote: > Sad news. I wonder if his web pages will survive him. If not, the > Internet Archive has archived the information. The latest is at: > http://web.archive.org/web/20120823060601/http://www.rt66.com/~shera/ The webarchive seems to be complete except that there is no link to the assembly language source code. Only the hex file is available. The QST article said thew source was available but I don't think it is unless perhaps some one here has a copy. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On Sun, Mar 24, 2013 at 4:12 AM, Stephen Tompsett (G8LYB) wrote: > Here's a copy of the source package (that claims to be for version 1.28) > that he sent me when I enquired about it many years ago. That's great. It needs to be some how linked to an archive of his article. No better memorial to an engineer than to have is work preserved in a public place. I read the assembly source code. I'm not a PIC expert but I've been doing software for 25+ years I and see that it is well written and easy to understand. Some day I'll transliterate this to run on a TI launchpad and will have to credit the author. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Just send me the link relative to archive.org of where the code should be found. -Original Message- From: Chris Albertson Sender: time-nuts-boun...@febo.com Date: Sun, 24 Mar 2013 11:31:50 To: ; Discussion of precise time and frequency measurement Reply-To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Brooks Shera On Sun, Mar 24, 2013 at 4:12 AM, Stephen Tompsett (G8LYB) wrote: > Here's a copy of the source package (that claims to be for version 1.28) > that he sent me when I enquired about it many years ago. That's great. It needs to be some how linked to an archive of his article. No better memorial to an engineer than to have is work preserved in a public place. I read the assembly source code. I'm not a PIC expert but I've been doing software for 25+ years I and see that it is well written and easy to understand. Some day I'll transliterate this to run on a TI launchpad and will have to credit the author. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
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Re: [time-nuts] Brooks Shera
Uh WTF. I am preserving his legacy. -Original Message- From: WB6BNQ Date: Sun, 24 Mar 2013 16:38:06 To: ; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Brooks Shera Really ? Well li...@lazygranch.com, I don't mind telling you I think your statement is rather crass and quite disrespectful. The gentleman is not even cold in his grave and all you can demonstrate is to grab his efforts for your own selfish purposes. Truly shameful, BillWB6BNQ li...@lazygranch.com wrote: Just send me the link relative to archive.org of where the code should be found. -Original Message- From: Chris Albertson Sender: time-nuts-boun...@febo.com Date: Sun, 24 Mar 2013 11:31:50 To: ; Discussion of precise time and frequency measurement Reply-To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Brooks Shera On Sun, Mar 24, 2013 at 4:12 AM, Stephen Tompsett (G8LYB) wrote: > Here's a copy of the source package (that claims to be for version 1.28) > that he sent me when I enquired about it many years ago. That's great. It needs to be some how linked to an archive of his article. No better memorial to an engineer than to have is work preserved in a public place. I read the assembly source code. I'm not a PIC expert but I've been doing software for 25+ years I and see that it is well written and easy to understand. Some day I'll transliterate this to run on a TI launchpad and will have to credit the author. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
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Re: [time-nuts] Brooks Shera
I wanted to build a GPSDO using the Brooks Shera design since I read the QST article. I asked him in Jan 2009 about his source code, because I wanted to change the PIC to a more modern one and add some functionality, and his response was that he already had changed it to a 16F876A and added a lot of improvements to the released code such as PC control of many parameters using a COM port and in his opinion it was better for me to order a pre-programmed PIC from him than trying to reinvent the wheel. I did it and also he was kind enough to provide me with all the hard-to-obtain parts. My chip has this last version (402NE is mentioned in the doc, but this is from 2007 and there is a later version), but probably it has the fuses set to avoid extracting the code. Maybe somebody has the hex or the source of this improved version, in the documentation it is mentioned that Bob Leichner (WO6W) collaborated with Brooks in this version so he can be a source of more info. Brooks also made a PC program for controlling the GPSDO and plotting its performance (EFC, ADEV, etc.). The program can be downloaded from: https://sites.google.com/site/bshera02/software and https://sites.google.com/site/bshera02/software2 (you need both downloads). I also have a description of the serial port commands accepted by the device. I have all parts and the PCB stored because I got a Trimble GPSDO, but I think this is the right time to assemble it, at least as a tribute to Brooks. If anybody wants the files, just ask. Best regards, Ignacio EB4APL On 24/03/2013 19:31, Chris Albertson wrote: On Sun, Mar 24, 2013 at 4:12 AM, Stephen Tompsett (G8LYB) wrote: Here's a copy of the source package (that claims to be for version 1.28) that he sent me when I enquired about it many years ago. That's great. It needs to be some how linked to an archive of his article. No better memorial to an engineer than to have is work preserved in a public place. I read the assembly source code. I'm not a PIC expert but I've been doing software for 25+ years I and see that it is well written and easy to understand. Some day I'll transliterate this to run on a TI launchpad and will have to credit the author. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On Sun, Mar 24, 2013 at 7:34 PM, EB4APL wrote: > I wanted to build a GPSDO using the Brooks Shera design since I read the QST > article. I asked him in Jan 2009 about his source code, because I wanted to > change the PIC to a more modern one and add some functionality This is a perfect example of why people need to publish the source. Make it GPL or whatever. But the version that was posted to this thread is close enough to the final version and it is easy to modify any why you like. I was going to build one of these too. Then I found out about a PIC-TIC which is quite a bit better at measuring the phase difference and today we have better parts and cheap FPGAs. The value of the Shera design is that it is simple enough to study and understand and then go build something that builds on Brooks' idea. Now that you can read the code and see the schematic people can study this for years. > https://sites.google.com/site/bshera02/software > and > https://sites.google.com/site/bshera02/software2 This is another example of a dead-end project. No source code. You'd have to start over from scratch to make even the smallest change (such as getting it to run on a new version of the OS or an iPad or whatever.) -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Another great ham passes on, I'm sorry I never had a chance to meet him. Is the GPS controller that Brooks published still useful today, or has it been superseded by something newer? I have a Motorola GPS receiver (PVT-6) with 1 pps output, and an HP oscillator (model number escapes me at the moment). I also have one of the $30 ebay rubidium modules (FE-5680A) that were discussed here in previous years. I only need a controller to tie them all together. Should I build Brooks' circuit to work with my old Motorola PVT-6 or should I look for something else (perhaps one of the Jupiter receivers with 10 kHz output)? The D/A chip in his design seems to be obsolete, his archived web site says to contact him for the chip but we can't do that anymore. Are they still available? Dan Schultz N8FGV ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On Mon, 25 Mar 2013 00:43:02 -0400 "Daniel Schultz" wrote: > Another great ham passes on, I'm sorry I never had a chance to meet him. Definitly a sad day > Is the GPS controller that Brooks published still useful today, or has it been > superseded by something newer? That highly depends on what you want and what you need. Shera's design is definitly one of the simplest GPSDOs out there. And with that it defines what the lowest complexity to get something accurate is. If the performance of this circuit is enough for you, i wouldn't go for anything else. Of course, if you need better performance or want to tinker and see what can be done with home made equipment, then you should go for different circuits. Attila Kinali -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
I think Brooks' design is worth studying. It is simple enough and uses 20 year old technology so even use old folks can follow how it works. Then you go off and build something else using current parts I have one of those cheaper Rb units too. But you set them by sending a command over the serial port. Not by a control voltage. The DAC is internal to the unit. I plan to use a $5 TI Launch Pad. But basically the same over all ideas he used. At $5 each with shipping included TI is losing money. The device is self programming via a USB connection. On Sun, Mar 24, 2013 at 9:43 PM, Daniel Schultz wrote: > Another great ham passes on, I'm sorry I never had a chance to meet him. > > Is the GPS controller that Brooks published still useful today, or has it been > superseded by something newer? I have a Motorola GPS receiver (PVT-6) with 1 > pps output, and an HP oscillator (model number escapes me at the moment). I > also have one of the $30 ebay rubidium modules (FE-5680A) that were discussed > here in previous years. I only need a controller to tie them all together. > > Should I build Brooks' circuit to work with my old Motorola PVT-6 or should I > look for something else (perhaps one of the Jupiter receivers with 10 kHz > output)? The D/A chip in his design seems to be obsolete, his archived web > site says to contact him for the chip but we can't do that anymore. Are they > still available? > > Dan Schultz N8FGV > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Chris, Can you point me to the web site where the TI Launch Pad is sold for $5 including shipping ? Thank you, BillWB6BNQ Chris Albertson wrote: > snip > > I plan to use a $5 TI Launch Pad. But > basically the same over all ideas he used. At $5 each with shipping > included TI is losing money. The device is self programming via a > USB connection. > > snip > > -- > > Chris Albertson > Redondo Beach, California > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Hello Bill. Here link : http://www.ti.com/ww/en/launchpad/overview_head.html 10 - 13$ TI kits. Regards. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of WB6BNQ Sent: Monday, March 25, 2013 10:01 AM To: Discussion of precise time and frequency measurement; Chris Albertson Subject: Re: [time-nuts] Brooks Shera Chris, Can you point me to the web site where the TI Launch Pad is sold for $5 including shipping ? Thank you, BillWB6BNQ Chris Albertson wrote: > snip > > I plan to use a $5 TI Launch Pad. But > basically the same over all ideas he used. At $5 each with shipping > included TI is losing money. The device is self programming via a > USB connection. > > snip > > -- > > Chris Albertson > Redondo Beach, California > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Brooks GPSDO may be 15 years old but is still perfect for today's applications. If you look at tvb's Tbolt plot or Ulrich's plots with and without sawtooth correction for a day or two the limit is GPS. The basic unit has a resolution of 1.73 E-13 in mode 7. Brooks uses a 40 bit filter. I have increased resolution using 100 MHz in stead of 24 and increasing filter time from 30 to 60 and 120 seconds. 240 is also an option, I would only recommend any thing above 30 seconds if you use a Rb. The only thing wrong is that chips that where available 15 years ago are now hard to find. My answer is a $ 1 gate array and if some one will step up to the plate and modify the available ASM code to generate the RS232 code to control a FE 5680A I will make a G/A design and a board design available. While at it also look at putting it in a 18 pin PIC. If interested contact me off list. With hundreds of 5680's out there many will appreciate a low cost simple solution. Working with the presently available ASM code now out there it will be a very small effort needed to transfer it to the latest version 1.402.1 when it becomes available. It will take some one willing and able to pick up at the point where the filter output drives the DAC and develops code that reads the info from the 5680 and generates the correction code. The 5680 does not control a DAC but the DDS in the 6.8 GHz loop. As to the input circuit, having looked at many alternatives I still thing it is the best for a 1 pps input from GPS and its limitations. Hope to have some data available of 1.402.1 driving a Morion in the next couple of days. I also have a couple of A&A boards with all original chips and some of my 100 MHz boards with components. Please contact me off list if interested. Bert Kehren Miami In a message dated 3/25/2013 2:30:36 A.M. Eastern Daylight Time, att...@kinali.ch writes: On Mon, 25 Mar 2013 00:43:02 -0400 "Daniel Schultz" wrote: > Another great ham passes on, I'm sorry I never had a chance to meet him. Definitly a sad day > Is the GPS controller that Brooks published still useful today, or has it been > superseded by something newer? That highly depends on what you want and what you need. Shera's design is definitly one of the simplest GPSDOs out there. And with that it defines what the lowest complexity to get something accurate is. If the performance of this circuit is enough for you, i wouldn't go for anything else. Of course, if you need better performance or want to tinker and see what can be done with home made equipment, then you should go for different circuits. Attila Kinali -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
The lack of synchronisers when crossing clock domains is a design flaw that should be corrected. Bruce ewkeh...@aol.com wrote: Brooks GPSDO may be 15 years old but is still perfect for today's applications. If you look at tvb's Tbolt plot or Ulrich's plots with and without sawtooth correction for a day or two the limit is GPS. The basic unit has a resolution of 1.73 E-13 in mode 7. Brooks uses a 40 bit filter. I have increased resolution using 100 MHz in stead of 24 and increasing filter time from 30 to 60 and 120 seconds. 240 is also an option, I would only recommend any thing above 30 seconds if you use a Rb. The only thing wrong is that chips that where available 15 years ago are now hard to find. My answer is a $ 1 gate array and if some one will step up to the plate and modify the available ASM code to generate the RS232 code to control a FE 5680A I will make a G/A design and a board design available. While at it also look at putting it in a 18 pin PIC. If interested contact me off list. With hundreds of 5680's out there many will appreciate a low cost simple solution. Working with the presently available ASM code now out there it will be a very small effort needed to transfer it to the latest version 1.402.1 when it becomes available. It will take some one willing and able to pick up at the point where the filter output drives the DAC and develops code that reads the info from the 5680 and generates the correction code. The 5680 does not control a DAC but the DDS in the 6.8 GHz loop. As to the input circuit, having looked at many alternatives I still thing it is the best for a 1 pps input from GPS and its limitations. Hope to have some data available of 1.402.1 driving a Morion in the next couple of days. I also have a couple of A&A boards with all original chips and some of my 100 MHz boards with components. Please contact me off list if interested. Bert Kehren Miami In a message dated 3/25/2013 2:30:36 A.M. Eastern Daylight Time, att...@kinali.ch writes: On Mon, 25 Mar 2013 00:43:02 -0400 "Daniel Schultz" wrote: Another great ham passes on, I'm sorry I never had a chance to meet him. Definitly a sad day Is the GPS controller that Brooks published still useful today, or has it been superseded by something newer? That highly depends on what you want and what you need. Shera's design is definitly one of the simplest GPSDOs out there. And with that it defines what the lowest complexity to get something accurate is. If the performance of this circuit is enough for you, i wouldn't go for anything else. Of course, if you need better performance or want to tinker and see what can be done with home made equipment, then you should go for different circuits. Attila Kinali ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Bruce, would you mind being more specific and offer a solution. Thanks Bert Kehren In a message dated 3/25/2013 7:09:41 A.M. Eastern Daylight Time, bruce.griffi...@xtra.co.nz writes: The lack of synchronisers when crossing clock domains is a design flaw that should be corrected. Bruce ewkeh...@aol.com wrote: > Brooks GPSDO may be 15 years old but is still perfect for today's > applications. If you look at tvb's Tbolt plot or Ulrich's plots with and without > sawtooth correction for a day or two the limit is GPS. The basic unit has a > resolution of 1.73 E-13 in mode 7. Brooks uses a 40 bit filter. I have > increased resolution using 100 MHz in stead of 24 and increasing filter time from > 30 to 60 and 120 seconds. 240 is also an option, I would only recommend > any thing above 30 seconds if you use a Rb. The only thing wrong is that > chips that where available 15 years ago are now hard to find. My answer is a $ > 1 gate array and if some one will step up to the plate and modify the > available ASM code to generate the RS232 code to control a FE 5680A I will make > a G/A design and a board design available. While at it also look at putting > it in a 18 pin PIC. If interested contact me off list. > With hundreds of 5680's out there many will appreciate a low cost simple > solution. Working with the presently available ASM code now out there it will > be a very small effort needed to transfer it to the latest version 1.402.1 > when it becomes available. It will take some one willing and able to pick > up at the point where the filter output drives the DAC and develops code > that reads the info from the 5680 and generates the correction code. The 5680 > does not control a DAC but the DDS in the 6.8 GHz loop. > As to the input circuit, having looked at many alternatives I still thing > it is the best for a 1 pps input from GPS and its limitations. Hope to have > some data available of 1.402.1 driving a Morion in the next couple of days. > I also have a couple of A&A boards with all original chips and some of my > 100 MHz boards with components. Please contact me off list if interested. > Bert Kehren Miami > > > > > > In a message dated 3/25/2013 2:30:36 A.M. Eastern Daylight Time, > att...@kinali.ch writes: > > On Mon, 25 Mar 2013 00:43:02 -0400 > "Daniel Schultz" wrote: > > >> Another great ham passes on, I'm sorry I never had a chance to meet him. >> > Definitly a sad day > > >> Is the GPS controller that Brooks published still useful today, or has >> > it been > >> superseded by something newer? >> > That highly depends on what you want and what you need. > > Shera's design is definitly one of the simplest GPSDOs out there. > And with that it defines what the lowest complexity to get something > accurate is. If the performance of this circuit is enough for you, > i wouldn't go for anything else. Of course, if you need better performance > or want to tinker and see what can be done with home made equipment, then > you should go for different circuits. > > Attila Kinali > > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On Mon, 25 Mar 2013 07:53:40 -0400 (EDT) ewkeh...@aol.com wrote: > In a message dated 3/25/2013 7:09:41 A.M. Eastern Daylight Time, > bruce.griffi...@xtra.co.nz writes: > > > The lack of synchronisers when crossing clock domains is a design flaw > > that should be corrected. > > Bruce, would you mind being more specific and offer a solution. > Thanks Bert Kehren Sorted by increasing amount of detail: http://en.wikipedia.org/wiki/Clock_domain_crossing http://www.eetimes.com/design/eda-design/4018520/Understanding-Clock-Domain-Crossing-Issues http://www.sunburst-design.com/papers/CummingsSNUG2008Boston_CDC.pdf I think with these it becomes obvious where the problem lies and what the solution is. Attila Kinali -- The trouble with you, Shev, is you don't say anything until you've saved up a whole truckload of damned heavy brick arguments and then you dump them all out and never look at the bleeding body mangled beneath the heap -- Tirin, The Dispossessed, U. Le Guin ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On 3/24/13 8:22 PM, Chris Albertson wrote: On Sun, Mar 24, 2013 at 7:34 PM, EB4APL wrote: I wanted to build a GPSDO using the Brooks Shera design since I read the QST article. I asked him in Jan 2009 about his source code, because I wanted to change the PIC to a more modern one and add some functionality This is a perfect example of why people need to publish the source. Make it GPL or whatever. That's a decision that the author gets to make. I've been on both the supplier and consumer side of that aspect. Sometimes I've published source, sometimes I haven't. There's a lot of factors involved, and the consumers need to respect the author: only the author knows all of them. One reason is that if one DOES release source, one will wind up supporting it, because generally, we all nice people and helpful, and it's hard to tell someone no when they send an email asking how to get it to compile on Version N+3 when you used version N, etc. This can be a real distraction from whatever else you are doing. One also DOES get a remarkable number of abusive emails when you don't provide support and you nicely tell them that. I guess, the first one is remarkable, after that, you go, "some people are just jerks" and let it ride. And then there's the folks who argue with you about your implementation or coding style. "I've rebuilt your program using .net 2.0 and C# instead of VB6". This is a real quandary.. On the one hand, you have no desire to support this offspring, but on the other, you would like credit for the underlying algorithms and initial work. But the version that was posted to this thread is close enough to the final version and it is easy to modify any why you like. I was going to build one of these too. Then I found out about a PIC-TIC which is quite a bit better at measuring the phase difference and today we have better parts and cheap FPGAs. The value of the Shera design is that it is simple enough to study and understand and then go build something that builds on Brooks' idea. Now that you can read the code and see the schematic people can study this for years. https://sites.google.com/site/bshera02/software and https://sites.google.com/site/bshera02/software2 This is another example of a dead-end project. No source code. You'd have to start over from scratch to make even the smallest change (such as getting it to run on a new version of the OS or an iPad or whatever.) The algorithms are well known and understood, and not very complex. Perhaps starting from scratch wouldn't be a bad thing if you're going to an entirely new platform. What works well in a dedicated microcontroller may not work so well in a multithreaded smartphone or media display device. I've been fighting a problem with what I thought would be a trivially simple web browser user interface. Turns out that modern browsers are entirely too smart, and it's very difficult to force the browser to not cache an image (e.g. I have an IMG tag pointing to "image.jpg" and I want to have it pick up the latest rev whenever the page refreshes) (Firefox is what I'm using, but they all have peculiarities) The point is that when you move to a qualitatively different platform (e.g. not just changing from a PIC model X to a PIC model Y), some architectural thought might be useful. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
> The lack of synchronisers when crossing clock domains is a design flaw > that should be corrected. > > Bruce > I think with these it becomes obvious where the problem lies and what > the solution is. > > Attila Kinali I realize there are many cases where clock domain considerations are important. But why does it matter in a device that is simply doing long-term 1PPS statistical sampling? Could one of you clock domain specialists actually spell out the GPSDO problem for the rest of us, nanosecond-by-nanosecond? Thanks, /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On 25 March 2013 13:36, Jim Lux wrote: > On 3/24/13 8:22 PM, Chris Albertson wrote: >> This is a perfect example of why people need to publish the source. >> Make it GPL or whatever. > > > That's a decision that the author gets to make. I've been on both the > supplier and consumer side of that aspect. Sometimes I've published source, > sometimes I haven't. There's a lot of factors involved, and the consumers > need to respect the author: only the author knows all of them. I've often wondered in there is a half-way house, for small projects like this, where one makes money from them, but where one would be happy to release the source code on ones death, or where one is sufficiently incapacitated to do anything with it. I could send the source to whoever wants it, but it would be useless without a decryption key. One gives the key to a wife, sibling or someone else so it could only be made available when that party agrees to make it available. To get around the possibility of an ex-wife deciding to get nasty, it could be done that there are two keys and both are necessary. A system like that would protect the author, but ensure that in the event of their death, the code is public. That license could be GPL, freeware of whatever else the author choses. I suspect Brooks Shera would have agreed to do something like that. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On Mon, Mar 25, 2013 at 5:44 AM, Attila Kinali wrote: > On Mon, 25 Mar 2013 07:53:40 -0400 (EDT) > ewkeh...@aol.com wrote: > >> In a message dated 3/25/2013 7:09:41 A.M. Eastern Daylight Time, >> bruce.griffi...@xtra.co.nz writes: >> >> > The lack of synchronisers when crossing clock domains is a design flaw >> > that should be corrected. >> >> Bruce, would you mind being more specific and offer a solution. I think Brooks' solution was to drive the phase of the two clocks to be 1024 counts apart. I think it selected "1024" and not zero just for this reason. If by chance the two are in phase to start with the built-in randomness of the 24MHz clock saves the day and then the control loop forces them eventually to be not in phase by 1024/24M seconds -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On Mon, Mar 25, 2013 at 6:36 AM, Jim Lux wrote: > The algorithms are well known and understood, and not very complex. Perhaps > starting from scratch wouldn't be a bad thing if you're going to an entirely > new platform. They are well known to people who already know. If you are new to the field it is good to have easy examples to study. about image caching, simplest way is to use a cgibin script rather then a static page. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
> A system like that would protect the author, but ensure that in the > event of their death, the code is public. That license could be GPL, > freeware of whatever else the author choses. I suspect Brooks Shera > would have agreed to do something like that. > We don't have to guess. Brooks wrote near the top of his source code file that it is "Free for noncommercial use". He gave it away to anyone who asked. But because he made pre programmed chips available apparently not many people asked. I think for many people a programmed PIC is simply a "magic black box" and assembly language source code is no more readable than the HEX file. So I doubt many builders asked for the code not when the magic boxes where available for a few bucks. But if you do look at it, it read "free for noncommercial use." So we don't have to guess at what he would have wanted. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Hi One key point in an earlier reference: "...Brooks made 300 pre-programmed (PIC) chips for people.." I'm sure I didn't get that exactly verbatim, but 300 is the number mentioned. We could debate endlessly weather the number is accurate or not, for the moment assume it's correct. The cost of the chips (programmed or otherwise) is and was trivial. Your menu decisions at lunch (small fires / large coke) cost you more than these chips. Cost was not an impediment to people getting parts. Availability of the chips was not a major issue in the early years. There was no mystery about who you asked. Brooks had the chips. He was easy to find on the internet. No major hunting was involved. The article is dated 1998. For the sake of this, say that Brooks was still active for 10 to 12 years after the article. That gets you to something like 25 to 30 chips a year. I'm sure it was not linear, but there's no way of knowing how non-linear it was. Based on my own junk box, I'd guess that if 30 chips went out, something less than 15 got powered up. I'm probably being overly optimistic at 50%. We now are at the ~15 year point after the article came out. I think it's a bit crazy to *expect* someone to be actively supporting a "< 15 a year" sort of charity 15 years later. If that's what someone wants to do as a hobby - fine. If his / her decision is to move on - that's also fine. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David Kirkby Sent: Monday, March 25, 2013 10:53 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Brooks Shera On 25 March 2013 13:36, Jim Lux wrote: > On 3/24/13 8:22 PM, Chris Albertson wrote: >> This is a perfect example of why people need to publish the source. >> Make it GPL or whatever. > > > That's a decision that the author gets to make. I've been on both the > supplier and consumer side of that aspect. Sometimes I've published source, > sometimes I haven't. There's a lot of factors involved, and the consumers > need to respect the author: only the author knows all of them. I've often wondered in there is a half-way house, for small projects like this, where one makes money from them, but where one would be happy to release the source code on ones death, or where one is sufficiently incapacitated to do anything with it. I could send the source to whoever wants it, but it would be useless without a decryption key. One gives the key to a wife, sibling or someone else so it could only be made available when that party agrees to make it available. To get around the possibility of an ex-wife deciding to get nasty, it could be done that there are two keys and both are necessary. A system like that would protect the author, but ensure that in the event of their death, the code is public. That license could be GPL, freeware of whatever else the author choses. I suspect Brooks Shera would have agreed to do something like that. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On Mon, Mar 25, 2013 at 2:56 PM, Tom Van Baak wrote: > I realize there are many cases where clock domain considerations are > important. But why does it matter in a device that is simply doing long-term > 1PPS statistical sampling? > > Could one of you clock domain specialists actually spell out the GPSDO > problem for the rest of us, nanosecond-by-nanosecond? It's hard to discuss this generally, so let's take an example design. I don't know Brooks Shera's design at all, so I don't know how applicable the following example is to it. In any case it is an illustration of the type of clock domain problems one can have while designing a GPSDO. Imagine you want to know how many ticks of a 10 MHz source (such as a VCXO) there are between two rising edges of an externally provided PPS. By externally provided I mean it is not derived from the 10 MHz VCXO. Most people today would do it with an FPGA. One way of doing it wrong is the following: - Have a free-running counter clocked off the VCXO, counting +1 at each tick. If this is a 32-bit counter it contains 32 flip-flops (FFs) that you take the output from. These outputs also go to a bunch of gates which feed the D inputs of those FFs. These gates implement the "+1". The VCXO output is hooked to the clk inputs of all FFs, so at every rising edge of the VCXO signal, a new value appears at the Q outputs of the FFs. This value is the old value plus 1. Sorry if I am explaining this at a too-easy level. The signals out of the FFs take some time to go through the gates, but the FPGA Place&Route tool knows (because you tell it so) that if the worst case combinational delay between any Q output of an FF and any D input of any FF is well below 100 ns, all is fine. This is the beauty of synchronous design. You tell the P&R tool what your clock period is and it makes sure all signals at D inputs are stable by the time the next rising edge of the clock comes. - Now you say "OK, I am going to freeze the value of that counter at every rising edge of PPS and store it, so a simple subtraction afterwards will tell me the period I am measuring". What happens if you tap the Q outputs of those 32 FFs and send these signals to the 32 D inputs of another bunch of FFs which are clocked by the PPS? The PPS rising edge can come anywhere withing the 100 ns period of your clock. Because of the different latencies for each line inside the FPGA, there are chances that some bits in the 32 bit word (as seen by the D inputs of the PPS-clocked FFs at the time of a PPS rising edge) have changed after a VCXO rising edge, while others still haven't. This can give you completely bogus values at the Q outputs of these FFs. You might think that you can do a software sanity check and fix the bogus values, but this is impossible. You cannot know which bits are wrong just by looking at this time-stamp. In addition to this problem, there is also the issue of metastability in FFs. If the rising edge of PPS as seen by an FF in its clk input is very close in time to a transition (rising or falling) in the signal hooked to its D input, the Q output can stay in a metastable state (neither '0' nor '1') for a long time. This is more or less important depending on what you are doing with these outputs further down in your design. It's generally very bad. So how do you do it properly? You bring the PPS into the VCXO clock domain. You can do this by feeding the PPS signal to a chain of three FFs clocked by the VCXO: - FF1 has its D input hooked to the PPS signal. - FF2 has its D input hooked to the Q output of FF1. - FF3 has its D input hooked to the Q output of FF2. The output of FF1 can be metastable from time to time, with a small but not negligible probability. The output of FF2 is for all practical purposes safe. For it to be metastable, you would need a doubly-unlikely event: that FF1's output has gone metastable in the previous clk tick and that the D input of FF2 is seeing an unsafe (far from '0' or '1', near the transition region) voltage at the time of the current tick's rising edge. Now if you tap the outputs of FF2 and FF3 and hook them to gates which implement (Q(FF2) and not Q(FF3)), the output of this combinational block is a nice 1-tick-long pulse which is '1' after detecting a rising edge of PPS. This pulse is in the VCXO clock domain, so you can safely use it as an ENABLE of the bank of 32 FFs you use to get a time stamp. This bank now gets clocked by the VCXO signal, so all FFs in the design are clocked by the same clock, and the P&R tool can do its job properly. I hope I understood your question well and this answers it. Cheers! Javier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On Mon, 25 Mar 2013 06:56:30 -0700 "Tom Van Baak" wrote: > > I think with these it becomes obvious where the problem lies and what > > the solution is. > I realize there are many cases where clock domain considerations are > important. But why does it matter in a device that is simply doing > long-term 1PPS statistical sampling? > > Could one of you clock domain specialists actually spell out the > GPSDO problem for the rest of us, nanosecond-by-nanosecond? I'm by far not an expert, but i try to explain it anyways: The PPS sampling is exactly the problem here. The PPS occurs at any given time relative to the 24MHz clock. This means setup and hold times can be violated in a synchronous circuit. In this case, the input to the 75HCT4520 is an AND connection of the 24MHz clock and the PPS. Due to this, the clock input to the counter in the 74HCT4520 can become very short, short enough that the minimum width of the clock pulse is violated (>15ns). Because of this, the behaviour of the counter is undefined and can lead not only to missing one count (which would be caught by the PI control loop as additional noise), but the output of the D-flip flops in the counter can switch or not switch depending on the wheather in Guatemala. Ie the output of the counter becomes (more or less) random. Which in turn means the lower 4 bit of the input to the PI control loop are wrong[1]. Or in terms of time, we might be off by +/-2^4*42ns=672ns, which is a major hit against the PI loop (like knocking it with a sledge hammer). Additionally, it is known that logic circuits can be caught nearly indefinitly in a meta stable state (until the next clock pulse), if the circuit has no provisions for this. Ie the output of the flip flops would not be 1 or 0, but something inbetween, with some negative effects on the circuitry downstream. HTH Attila Kinali [1] I ignore the additional +/-1 of bit 5 for clarity -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Actually, most modern FFs are hardened against metastability so often a single synchronizer will do especially if it is feeding a synchronous circuit. David On 3/25/13 1:56 PM, Attila Kinali wrote: On Mon, 25 Mar 2013 06:56:30 -0700 "Tom Van Baak" wrote: I think with these it becomes obvious where the problem lies and what the solution is. I realize there are many cases where clock domain considerations are important. But why does it matter in a device that is simply doing long-term 1PPS statistical sampling? Could one of you clock domain specialists actually spell out the GPSDO problem for the rest of us, nanosecond-by-nanosecond? I'm by far not an expert, but i try to explain it anyways: The PPS sampling is exactly the problem here. The PPS occurs at any given time relative to the 24MHz clock. This means setup and hold times can be violated in a synchronous circuit. In this case, the input to the 75HCT4520 is an AND connection of the 24MHz clock and the PPS. Due to this, the clock input to the counter in the 74HCT4520 can become very short, short enough that the minimum width of the clock pulse is violated (>15ns). Because of this, the behaviour of the counter is undefined and can lead not only to missing one count (which would be caught by the PI control loop as additional noise), but the output of the D-flip flops in the counter can switch or not switch depending on the wheather in Guatemala. Ie the output of the counter becomes (more or less) random. Which in turn means the lower 4 bit of the input to the PI control loop are wrong[1]. Or in terms of time, we might be off by +/-2^4*42ns=672ns, which is a major hit against the PI loop (like knocking it with a sledge hammer). Additionally, it is known that logic circuits can be caught nearly indefinitly in a meta stable state (until the next clock pulse), if the circuit has no provisions for this. Ie the output of the flip flops would not be 1 or 0, but something inbetween, with some negative effects on the circuitry downstream. HTH Attila Kinali [1] I ignore the additional +/-1 of bit 5 for clarity ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On Mon, 25 Mar 2013 18:56:34 +0100 Attila Kinali wrote: > Because of this, the behaviour of the > counter is undefined and can lead not only to missing one count (which > would be caught by the PI control loop as additional noise), but the output > of the D-flip flops in the counter can switch or not switch depending > on the wheather in Guatemala. Maybe to clarify here: The reason why all 4 flip-flops (and thus all 4 output bits) are affected is because the 74HC4520 passes the input clock to all four flip-flops (see figure 5 in http://www.nxp.com/documents/data_sheet/74HC_HCT4520_CNV.pdf) Attila Kinali -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Hello, I am deeply affected by Brookes Shera' s death. Years ago I had only a few mail-contacts with him and he's been very helpful and friendly. I believe that he would have assisted to introduce improvements and further details in his design if he would have been able to. He did provide me the source code of the older version 1.28 and the bin file 1.33 under certain restrictions. I promised to respect his conditions. His personal written words were (as direct copy): > Hi Arnold, > > Good to hear from you again. I saw your message on timenuts and thought I should reply. I have sent the source code to many people. But I do ask that they agree to my little request: > > >> * For people that request the source code I have a standard request. >> >> the standard request- >> >> >> Thanks for your interest in the source code for the PIC processor used in >> my gps-disciplined frequency standard (QST, July '98). I am happy to >> provide the source for its possible instructional value or as a basis of >> further experimentation. >> >> The code is PIC assembly language but it is highly commented so even if >> you are not very familiar with the PIC instruction set or architecture it >> may be possible to follow the logic of the code. To make this a little >> easier I have written a short description of the software. >> >> At the moment I have no plans to commercialize the code or the >> controller, however I have invested quite a bit of time in its >> development and I want to preserve my intellectual property rights to the >> design. >> >> Therefore, I can provide the software to you with the following >> restrictions. >> >> 1. The code will not be used in the development or implementation of a >> commercial product. >> >> 2. The code is exclusively for personal use and will not be distributed >> to other individuals. >> >> 3. Useful modifications or enhancements to the code will be shared with >> me, and in binary form with the community of amateur >> experimenters. Such modifications include translation of the PIC code to >> run on other platforms. >> >> If these conditions are acceptable to you please send me a note that >> includes the above three restrictions. I can e-mail you a zip-compressed >> attachment that includes the source code and the description mentioned >> above. >> >> I hope you will understand my motivation for these restrictions, which >> arise from the somewhat conflicting desires to make the code widely >> available to encourage further experimentation while preventing >> commercialization of it by others. >> >> Regards, Brooks >Hi Arnold, >I am attaching the source code and a notes file that is a bit out of date but it explains the overall organization of the code. The asm file is fairly well documented also. >Let me know if you have any questions, and have fun. >Brooks I think that this is still valid in case he didn't express a change, and it should be respected. But I am as well interested that the development based on his design does continue and improvements will be and introduced. Unfortunately I have no skills in programming and microprocessor design. I am convinced that out there are a lot experts in the group well capable to proceed in Brookes' mind. Have fun, as he said, we will miss him, kind regards Arnold Am 25.03.2013 14:36, schrieb Jim Lux: > On 3/24/13 8:22 PM, Chris Albertson wrote: >> On Sun, Mar 24, 2013 at 7:34 PM, EB4APL >> wrote: >>> I wanted to build a GPSDO using the Brooks Shera design since I read >>> the QST >>> article. I asked him in Jan 2009 about his source code, because I >>> wanted to >>> change the PIC to a more modern one and add some functionality >> >> This is a perfect example of why people need to publish the source. >> Make it GPL or whatever. > > That's a decision that the author gets to make. I've been on both the > supplier and consumer side of that aspect. Sometimes I've published > source, sometimes I haven't. There's a lot of factors involved, and > the consumers need to respect the author: only the author knows all of > them. > > One reason is that if one DOES release source, one will wind up > supporting it, because generally, we all nice people and helpful, and > it's hard to tell someone no when they send an email asking how to get > it to compile on Version N+3 when you used version N, etc. This can > be a real distraction from whatever else you are doing. > > One also DOES get a remarkable number of abusive emails when you don't > provide support and you nicely tell them that. I guess, the first one > is remarkable, after that, you go, "some people are just jerks" and > let it ride. > > And then there's the folks who argue with you about your > implementation or coding style. "I've rebuilt your program using .net > 2.0 and C# instead of VB6". This is a real quandary.. On the one hand, > you have no desire to suppo
Re: [time-nuts] Brooks Shera
On Mon, 25 Mar 2013 09:23:21 -0700 Chris Albertson wrote: > On Mon, Mar 25, 2013 at 6:36 AM, Jim Lux wrote: > > > The algorithms are well known and understood, and not very complex. Perhaps > > starting from scratch wouldn't be a bad thing if you're going to an entirely > > new platform. > > They are well known to people who already know. If you are new to the > field it is good to have easy examples to study. Well.. there are many good textbooks on control theory. A lot of them with very little math and lots of explenations so that even people without a PhD in math can understand them. For this particular application i would recomened to have a look at "Phase Locked Loops" by Roland Best. It covers how control loops are designed with the explicit application of PLLs and thus leaving a lot of math and theory out that would be needed for general control loops but is superficial for PLLs or merged into other sub-blocks. Beside this, my experience is that most control loops can live with a couple of simplifications. Ie you will get a loop that works in 90% of all cases like the "ideal" loop, but you will have worse performance (or oscillations) at the corner cases. This is especially the case when you know that you hardly get any steps or hits in your loop. Attila Kinali -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
> Ie the output of the counter becomes > (more or less) random. Which in turn means the lower 4 bit of the > input to the PI control loop are wrong[1]. Or in terms of time, we > might be off by +/-2^4*42ns=672ns, which is a major hit against the > PI loop (like knocking it with a sledge hammer). But these numbers don't go directly to the PI loop, there is a software layer between that can inspect for outliers. This is how engineers can reduce costs by knowing when something needs to be perfect and when it does not need to be. In the end the controller works about as good as it needs to.What saves this is the unstably of the cheap 24MHz clock. If the clock problem happens the randomness will make it soon stop happening and the software can just ignore the outliers. You have to look at the whole system and not just the hardware. Much of the functionality is in the software. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On Mon, 25 Mar 2013 14:03:23 -0400 David McGaw wrote: > Actually, most modern FFs are hardened against metastability so often a > single synchronizer will do especially if it is feeding a synchronous > circuit. I would not count on that. Most 74xx that hobbyists use are from the HC and HCT families. These have been designed in the 70s (IIRC) and i very much doubt that any of the manufacturers changed anything in their design since then. Attila Kinali -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On Mon, 25 Mar 2013 11:18:06 -0700 Chris Albertson wrote: > > Ie the output of the counter becomes > > (more or less) random. Which in turn means the lower 4 bit of the > > input to the PI control loop are wrong[1]. Or in terms of time, we > > might be off by +/-2^4*42ns=672ns, which is a major hit against the > > PI loop (like knocking it with a sledge hammer). > > But these numbers don't go directly to the PI loop, there is a > software layer between that can inspect for outliers. The problem here is that these outliers need not be a seldom occurence. If you take a LEA6-T as PPS source, you get the PPS pulse within +/-10ns in 90% of the cases. The 24MHz clock is, even though it's a cheap crystal, still a crystal. So you can assume a stability of better than 10^-7 short term (couple of seconds to a few minutes), probably in the range of 10^-8 to 10^-9. The window for metastability is 15ns (minimum clock pulse width). Now we have two things to consider: 1) Both the clock and the PPS are relatively stable compared to the "size" of the 15ns. Ie if we ever get into region of metastability, the probability that one of the next PPS will trigger again a metastable condition is relatively high. 2) We have a 24MHz clock, which means the clock pulse width is 20ns (T=1/24MHz, T/2 = 20ns). Ie the probability that our clock pulse is too short is 75% (15ns/20ns). I dont know why this isnt a big issue with the Shera GPSDO. I guess that the specs of the 74HC4520 are very conservative an that the minimum clock pulse length is rather in the range of 5ns than 15ns for most devices and operation temperatures. It might also be that the probability of bits being affected is less for the upper bits than for the lower bits. Or the PI loop is stable enough to deal with the additional noise. Attila Kinali -- The people on 4chan are like brilliant psychologists who also happen to be insane and gross. -- unknown ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
There is a company Death Switch which offers a service which sends out an email or multiple emails upon your demise or incapacitation The basic idea if you keep sending the service keepalives it does not send the email. Sort of like a dead mans switch on a locomotive Sent from my iPhone On Mar 25, 2013, at 10:53 AM, David Kirkby wrote: > On 25 March 2013 13:36, Jim Lux wrote: >> On 3/24/13 8:22 PM, Chris Albertson wrote: > >>> This is a perfect example of why people need to publish the source. >>> Make it GPL or whatever. >> >> >> That's a decision that the author gets to make. I've been on both the >> supplier and consumer side of that aspect. Sometimes I've published source, >> sometimes I haven't. There's a lot of factors involved, and the consumers >> need to respect the author: only the author knows all of them. > > I've often wondered in there is a half-way house, for small projects > like this, where one makes money from them, but where one would be > happy to release the source code on ones death, or where one is > sufficiently incapacitated to do anything with it. > > I could send the source to whoever wants it, but it would be useless > without a decryption key. One gives the key to a wife, sibling or > someone else so it could only be made available when that party agrees > to make it available. > > To get around the possibility of an ex-wife deciding to get nasty, it > could be done that there are two keys and both are necessary. > > A system like that would protect the author, but ensure that in the > event of their death, the code is public. That license could be GPL, > freeware of whatever else the author choses. I suspect Brooks Shera > would have agreed to do something like that. > > Dave > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Minimum clock width is not the window for metastability. That is usually 10s to 100s of picoseconds. On 3/25/13 3:20 PM, Attila Kinali wrote: On Mon, 25 Mar 2013 11:18:06 -0700 Chris Albertson wrote: Ie the output of the counter becomes (more or less) random. Which in turn means the lower 4 bit of the input to the PI control loop are wrong[1]. Or in terms of time, we might be off by +/-2^4*42ns=672ns, which is a major hit against the PI loop (like knocking it with a sledge hammer). But these numbers don't go directly to the PI loop, there is a software layer between that can inspect for outliers. The problem here is that these outliers need not be a seldom occurence. If you take a LEA6-T as PPS source, you get the PPS pulse within +/-10ns in 90% of the cases. The 24MHz clock is, even though it's a cheap crystal, still a crystal. So you can assume a stability of better than 10^-7 short term (couple of seconds to a few minutes), probably in the range of 10^-8 to 10^-9. The window for metastability is 15ns (minimum clock pulse width). Now we have two things to consider: 1) Both the clock and the PPS are relatively stable compared to the "size" of the 15ns. Ie if we ever get into region of metastability, the probability that one of the next PPS will trigger again a metastable condition is relatively high. 2) We have a 24MHz clock, which means the clock pulse width is 20ns (T=1/24MHz, T/2 = 20ns). Ie the probability that our clock pulse is too short is 75% (15ns/20ns). I dont know why this isnt a big issue with the Shera GPSDO. I guess that the specs of the 74HC4520 are very conservative an that the minimum clock pulse length is rather in the range of 5ns than 15ns for most devices and operation temperatures. It might also be that the probability of bits being affected is less for the upper bits than for the lower bits. Or the PI loop is stable enough to deal with the additional noise. Attila Kinali ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
There are essentially 4 clock domains in the circuit 1) PPS 2) Divided down 10MHz (~300kHz) 3) 24 MHz 4) The microprocessor internal clock ( the micro probably has internal synchronisers for at least some external inputs). Depending on internal delays and jitter this may be regarded as synchronous with the 24MHz signal. The required fix is relatively simple: 1) use a 2 stage synchroniser (clocked at 24MHz) plus an additional FF to generate a 1 clock period duration pulse on each leading edge of the PPS input 2) use a 2 stage synchroniser (clocked at 24MHz) plus an additional FF to generate a 1 clock period duration pulse on each leading edge of the ~300KHz input The synchronised PPS and 300KHz signals are now in the 24MHz clock domain and can be used to generate a synchronised gate (or enable) signal with a duration equal to the time interval between the synchronised PPS and the next synchronised 300KHz pulses for a ripple (or synchronous) count chain. Bruce ewkeh...@aol.com wrote: Bruce, would you mind being more specific and offer a solution. Thanks Bert Kehren In a message dated 3/25/2013 7:09:41 A.M. Eastern Daylight Time, bruce.griffi...@xtra.co.nz writes: The lack of synchronisers when crossing clock domains is a design flaw that should be corrected. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
On Mon, Mar 25, 2013 at 12:20 PM, Attila Kinali wrote: The PPS signal is not sent direct to the 74HC4520. The PPS first drives "Phase Detector 3" that is built into the 4046 chip. this is an RS flip flop. Notice it is "RS3 OUT" that drives the 4520.RS3 uses both the PPS signal and the divided down VCXO to create "RS3 OUT" I think this gives a minimum pulse width, I'm not sure > I dont know why this isnt a big issue with the Shera GPSDO. > I guess that the specs of the 74HC4520 are very conservative > an that the minimum clock pulse length is rather in the range > of 5ns than 15ns for most devices and operation temperatures. > It might also be that the probability of bits being affected > is less for the upper bits than for the lower bits. > Or the PI loop is stable enough to deal with the additional noise. > > > > Attila Kinali > -- > The people on 4chan are like brilliant psychologists > who also happen to be insane and gross. > -- unknown > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
I have version 1.34a that he sent me in 2008. In light of his wishes, please contact me directly if you would like a copy. David On 3/24/13 7:12 AM, Stephen Tompsett (G8LYB) wrote: Here's a copy of the source package (that claims to be for version 1.28) that he sent me when I enquired about it many years ago. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Hi The gotcha with using the XO as a "spreading source" is the hanging bridge issue. As long as temperature (or what ever) is constantly changing the XO all the averaging stuff works out. A GPS with a sawtooth output (and no correction) is doing the same thing. The problem comes in when the XO settles down and runs at one frequency. That may sound impossible, but it's not. Injection locking is one way to make it happen. There are a couple of others. When the averaging stops, you get a dead spot. You don't get a glitch, you just loose resolution. The practical effect is a step in the input rather than a smooth transition. Not easy to spot…. Bob On Mar 25, 2013, at 6:41 PM, Richard H McCorkle wrote: > Hi Tom, > > In the Shera design the instability of the XO timebase is > a key factor in improving the 30-second update resolution. > With the XO drift varying the sample point across the 1PPS > and 312.5 KHz edges the samples are constantly varying and > the average of the samples has a resolution much closer to > (1/CLK)/30 or 1.4ns. If both signals were synchronized > with the clock the start and stop edges of every sample > would fall exactly on a clock. In lock the odds of the > sources having a sample-to-sample variation greater than > 1 clock period (+/- 41.7ns) over the 30 second sample > period is low. So the probability is high that you would > get 30 identical samples with an average resolution much > closer to 41.7ns (+/- 1 clock). > The counter clock and asynchronous gate are applied to > an AND gate in the CD4520 that drives all 4 stages so when > an asynchronous gate edge and clock are coincident a short > clock pulse is generated and the setup and hold times of > the CD4520 counter are not met. Under these conditions the > first 4 stages in the 4520 could end up in an indeterminate > state and the input to the 4040 would be questionable. The > counter should settle to some value by the next clock, > but the value could be up to +/- 31 counts different than > it should be. Shera gates multiple samples into the > counter with a single read/reset per 30-second update so > multiple uncertainties can be introduced in the accumulated > count. > Recognizing the probability of asynchronous gating > resulting in glitches in the data Shera uses a de-glitch > routine in modes 4-7 that detects any 30-second value that > exceeds +/- 30 counts from the previous value as a glitch > and uses the previous value when this condition is detected. > This is far from ideal as multiple errors could be > accumulated with an average value less than +/- 30 counts > per update, but it does handle the occasional glitch when > the gate and XO edges are coincident and a >30 count error > results. The XO stability usually insures coincidence will > be short lived, but multiple 30-second glitched samples > do occur, so a 3 glitched update (90-sec) limit is included. > During my early work on upgrading the Shera a number of > different counter designs with asynchronous gating were > evaluated. I settled on the AC163 as the clock is not > gated directly so no short clock pulses are ever applied to > the stages. Instead the /Q to D is gated and the previous > Q is passed to the next stage on the clock to determine if > it should advance. The gate to clock setup time is 2.5ns > with a hold time of -3ns, so if the setup time is met the > first stage advances, but if it rises and falls immediately > around the clock no advance occurs. This design reduces the > possible uncertainty with coincident gate and clock to > the first stage only (+/- 1 count) but with the hold time > smaller than the setup time typically no glitch will occur. > A 100 MHz XO driving an AC163 prescaler feeding TMR1 was > used with asynchronous gating. Each sample was read, added > to a software accumulator, and the counter reset after > every sample. In testing this asynchronous gated design it > produced no glitches (+/- 30 counts from the previous > sample) during 1 year of continuous operation but still > has the advantage of good sample averaging over the > 30-second update period for a phase resolution of 330ps. > Of course the ideal to get the optimum data out of the > GPS is to use a TIC with 1ns resolution and apply GPS > sawtooth correction to reduce the uncertainty in every > sample. To insure the counter value is correct you need > to synchronize the start and stop events to the clock > so only whole clock cycles are counted, but then you are > limited to the resolution of the clock. This is where > interpolation can be used to get the desired resolution > even though the counter resolution is limited to the > clock period. In the Interpolating Discipline Controller > (IDC) the disciplined source is multiplied to 40 MHz for > the TIC timebase and used to produce a 10us delayed > 50 KHz phase detector reference. The GPS 1PPS is > synchronized to the 40 MHz clock to start the counter, > with an interpolator determining the 1PPS to clo
Re: [time-nuts] Brooks Shera
As to the latest code Brooks did not release compiled or ASM code. Prior codes where released with an agreement. In due time his wife Karen Stoll will make a decision that will satisfy time nuts. Stay tuned. Bert Kehren In a message dated 3/25/2013 6:13:56 P.M. Eastern Daylight Time, n1...@alum.dartmouth.org writes: I have version 1.34a that he sent me in 2008. In light of his wishes, please contact me directly if you would like a copy. David On 3/24/13 7:12 AM, Stephen Tompsett (G8LYB) wrote: > Here's a copy of the source package (that claims to be for version > 1.28) that he sent me when I enquired about it many years ago. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
Hi Tom, In the Shera design the instability of the XO timebase is a key factor in improving the 30-second update resolution. With the XO drift varying the sample point across the 1PPS and 312.5 KHz edges the samples are constantly varying and the average of the samples has a resolution much closer to (1/CLK)/30 or 1.4ns. If both signals were synchronized with the clock the start and stop edges of every sample would fall exactly on a clock. In lock the odds of the sources having a sample-to-sample variation greater than 1 clock period (+/- 41.7ns) over the 30 second sample period is low. So the probability is high that you would get 30 identical samples with an average resolution much closer to 41.7ns (+/- 1 clock). The counter clock and asynchronous gate are applied to an AND gate in the CD4520 that drives all 4 stages so when an asynchronous gate edge and clock are coincident a short clock pulse is generated and the setup and hold times of the CD4520 counter are not met. Under these conditions the first 4 stages in the 4520 could end up in an indeterminate state and the input to the 4040 would be questionable. The counter should settle to some value by the next clock, but the value could be up to +/- 31 counts different than it should be. Shera gates multiple samples into the counter with a single read/reset per 30-second update so multiple uncertainties can be introduced in the accumulated count. Recognizing the probability of asynchronous gating resulting in glitches in the data Shera uses a de-glitch routine in modes 4-7 that detects any 30-second value that exceeds +/- 30 counts from the previous value as a glitch and uses the previous value when this condition is detected. This is far from ideal as multiple errors could be accumulated with an average value less than +/- 30 counts per update, but it does handle the occasional glitch when the gate and XO edges are coincident and a >30 count error results. The XO stability usually insures coincidence will be short lived, but multiple 30-second glitched samples do occur, so a 3 glitched update (90-sec) limit is included. During my early work on upgrading the Shera a number of different counter designs with asynchronous gating were evaluated. I settled on the AC163 as the clock is not gated directly so no short clock pulses are ever applied to the stages. Instead the /Q to D is gated and the previous Q is passed to the next stage on the clock to determine if it should advance. The gate to clock setup time is 2.5ns with a hold time of -3ns, so if the setup time is met the first stage advances, but if it rises and falls immediately around the clock no advance occurs. This design reduces the possible uncertainty with coincident gate and clock to the first stage only (+/- 1 count) but with the hold time smaller than the setup time typically no glitch will occur. A 100 MHz XO driving an AC163 prescaler feeding TMR1 was used with asynchronous gating. Each sample was read, added to a software accumulator, and the counter reset after every sample. In testing this asynchronous gated design it produced no glitches (+/- 30 counts from the previous sample) during 1 year of continuous operation but still has the advantage of good sample averaging over the 30-second update period for a phase resolution of 330ps. Of course the ideal to get the optimum data out of the GPS is to use a TIC with 1ns resolution and apply GPS sawtooth correction to reduce the uncertainty in every sample. To insure the counter value is correct you need to synchronize the start and stop events to the clock so only whole clock cycles are counted, but then you are limited to the resolution of the clock. This is where interpolation can be used to get the desired resolution even though the counter resolution is limited to the clock period. In the Interpolating Discipline Controller (IDC) the disciplined source is multiplied to 40 MHz for the TIC timebase and used to produce a 10us delayed 50 KHz phase detector reference. The GPS 1PPS is synchronized to the 40 MHz clock to start the counter, with an interpolator determining the 1PPS to clock delay with 1ns resolution. The 50 KHz stop signal is also synchronized to the 40 MHz clock to equalize the start and stop delays, but since both are derived from the disciplined source their delay is constant and a stop interpolator is not required. The sample is read from the counter, multiplied by 25 to 1ns resolution, the interpolated start delay is added, and the result is added to a software accumulator over the update period. A separate PIC accumulates the sawtooth corrections over the update period and at update the accumulated sawtooth correction is added to the accumulator before the data is passed to the filter. The GPS sawtooth correction removes the sawtooth variation and provides stable data into the filter for 33ps resolution phase data per 30-second update. An interesting point of the IDC design is a single interpolator is used so there
Re: [time-nuts] Brooks Shera
Richard H McCorkle wrote: Hi Tom, In the Shera design the instability of the XO timebase is a key factor in improving the 30-second update resolution. With the XO drift varying the sample point across the 1PPS and 312.5 KHz edges the samples are constantly varying and the average of the samples has a resolution much closer to (1/CLK)/30 or 1.4ns. If both signals were synchronized with the clock the start and stop edges of every sample would fall exactly on a clock. In lock the odds of the sources having a sample-to-sample variation greater than 1 clock period (+/- 41.7ns) over the 30 second sample period is low. So the probability is high that you would get 30 identical samples with an average resolution much closer to 41.7ns (+/- 1 clock). The above assertion is not correct if the inputs to the synchroniser(s) are asynchronous to the synchroniser clock. The gate period will have a bounded (neglecting the effect of metastability at the output of the synchronisers) variation of +- 1 count. Provided that the synchroniser (and counter) clock and the divided down disciplined oscillator clock meet the conditions outlined by David Chu in: http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1974-06.pdf In practice these conditions may be difficult to meet without adequate random phase modulation of PPS (and the divided down disciplined oscillator signal). Alternatively phase modulating the synchroniser/counter clock is perhaps simpler. The sawtooth phase modulation of the PPS signal output produced by many timing GPS receivers isnt sufficiently random to be particularly useful. The counter clock and asynchronous gate are applied to an AND gate in the CD4520 that drives all 4 stages so when an asynchronous gate edge and clock are coincident a short clock pulse is generated and the setup and hold times of the CD4520 counter are not met. Under these conditions the first 4 stages in the 4520 could end up in an indeterminate state and the input to the 4040 would be questionable. The counter should settle to some value by the next clock, but the value could be up to +/- 31 counts different than it should be. Shera gates multiple samples into the counter with a single read/reset per 30-second update so multiple uncertainties can be introduced in the accumulated count. Recognizing the probability of asynchronous gating resulting in glitches in the data Shera uses a de-glitch routine in modes 4-7 that detects any 30-second value that exceeds +/- 30 counts from the previous value as a glitch and uses the previous value when this condition is detected. This is far from ideal as multiple errors could be accumulated with an average value less than +/- 30 counts per update, but it does handle the occasional glitch when the gate and XO edges are coincident and a>30 count error results. The XO stability usually insures coincidence will be short lived, but multiple 30-second glitched samples do occur, so a 3 glitched update (90-sec) limit is included. During my early work on upgrading the Shera a number of different counter designs with asynchronous gating were evaluated. I settled on the AC163 as the clock is not gated directly so no short clock pulses are ever applied to the stages. Instead the /Q to D is gated and the previous Q is passed to the next stage on the clock to determine if it should advance. The gate to clock setup time is 2.5ns with a hold time of -3ns, so if the setup time is met the first stage advances, but if it rises and falls immediately around the clock no advance occurs. This design reduces the possible uncertainty with coincident gate and clock to the first stage only (+/- 1 count) but with the hold time smaller than the setup time typically no glitch will occur. A 100 MHz XO driving an AC163 prescaler feeding TMR1 was used with asynchronous gating. Each sample was read, added to a software accumulator, and the counter reset after every sample. In testing this asynchronous gated design it produced no glitches (+/- 30 counts from the previous sample) during 1 year of continuous operation but still has the advantage of good sample averaging over the 30-second update period for a phase resolution of 330ps. Of course the ideal to get the optimum data out of the GPS is to use a TIC with 1ns resolution and apply GPS sawtooth correction to reduce the uncertainty in every sample. To insure the counter value is correct you need to synchronize the start and stop events to the clock so only whole clock cycles are counted, but then you are limited to the resolution of the clock. This is where interpolation can be used to get the desired resolution even though the counter resolution is limited to the clock period. In the Interpolating Discipline Controller (IDC) the disciplined source is multiplied to 40 MHz for the TIC timebase and used to produce a 10us delayed 50 KHz phase detector reference. The GPS 1PPS is synchronized to the 40 MHz clock to start the counter, with an interpolator determin
Re: [time-nuts] Brooks Shera
Hi Using the GPS sawtooth as a source of randomness is dangerous. It can stop moving for minutes at a time if the conditions happen to be just right (or in this case wrong). Of course lack of randomization isn't your only problem when this happens. The (likely substantial) offset in the data is also a significant issue. Bob On Mar 25, 2013, at 8:35 PM, Bruce Griffiths wrote: > Richard H McCorkle wrote: >> Hi Tom, >> >> In the Shera design the instability of the XO timebase is >> a key factor in improving the 30-second update resolution. >> With the XO drift varying the sample point across the 1PPS >> and 312.5 KHz edges the samples are constantly varying and >> the average of the samples has a resolution much closer to >> (1/CLK)/30 or 1.4ns. If both signals were synchronized >> with the clock the start and stop edges of every sample >> would fall exactly on a clock. In lock the odds of the >> sources having a sample-to-sample variation greater than >> 1 clock period (+/- 41.7ns) over the 30 second sample >> period is low. So the probability is high that you would >> get 30 identical samples with an average resolution much >> closer to 41.7ns (+/- 1 clock). >> > The above assertion is not correct if the inputs to the synchroniser(s) are > asynchronous to the synchroniser clock. > The gate period will have a bounded (neglecting the effect of metastability > at the output of the synchronisers) variation of +- 1 count. > Provided that the synchroniser (and counter) clock and the divided down > disciplined oscillator clock meet the conditions outlined by David Chu in: > http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1974-06.pdf > > In practice these conditions may be difficult to meet without adequate random > phase modulation of PPS (and the divided down disciplined oscillator signal). > Alternatively phase modulating the synchroniser/counter clock is perhaps > simpler. > The sawtooth phase modulation of the PPS signal output produced by many > timing GPS receivers isnt sufficiently random to be particularly useful. >> The counter clock and asynchronous gate are applied to >> an AND gate in the CD4520 that drives all 4 stages so when >> an asynchronous gate edge and clock are coincident a short >> clock pulse is generated and the setup and hold times of >> the CD4520 counter are not met. Under these conditions the >> first 4 stages in the 4520 could end up in an indeterminate >> state and the input to the 4040 would be questionable. The >> counter should settle to some value by the next clock, >> but the value could be up to +/- 31 counts different than >> it should be. Shera gates multiple samples into the >> counter with a single read/reset per 30-second update so >> multiple uncertainties can be introduced in the accumulated >> count. >> Recognizing the probability of asynchronous gating >> resulting in glitches in the data Shera uses a de-glitch >> routine in modes 4-7 that detects any 30-second value that >> exceeds +/- 30 counts from the previous value as a glitch >> and uses the previous value when this condition is detected. >> This is far from ideal as multiple errors could be >> accumulated with an average value less than +/- 30 counts >> per update, but it does handle the occasional glitch when >> the gate and XO edges are coincident and a>30 count error >> results. The XO stability usually insures coincidence will >> be short lived, but multiple 30-second glitched samples >> do occur, so a 3 glitched update (90-sec) limit is included. >> During my early work on upgrading the Shera a number of >> different counter designs with asynchronous gating were >> evaluated. I settled on the AC163 as the clock is not >> gated directly so no short clock pulses are ever applied to >> the stages. Instead the /Q to D is gated and the previous >> Q is passed to the next stage on the clock to determine if >> it should advance. The gate to clock setup time is 2.5ns >> with a hold time of -3ns, so if the setup time is met the >> first stage advances, but if it rises and falls immediately >> around the clock no advance occurs. This design reduces the >> possible uncertainty with coincident gate and clock to >> the first stage only (+/- 1 count) but with the hold time >> smaller than the setup time typically no glitch will occur. >> A 100 MHz XO driving an AC163 prescaler feeding TMR1 was >> used with asynchronous gating. Each sample was read, added >> to a software accumulator, and the counter reset after >> every sample. In testing this asynchronous gated design it >> produced no glitches (+/- 30 counts from the previous >> sample) during 1 year of continuous operation but still >> has the advantage of good sample averaging over the >> 30-second update period for a phase resolution of 330ps. >> Of course the ideal to get the optimum data out of the >> GPS is to use a TIC with 1ns resolution and apply GPS >> sawtooth correction to reduce the uncertainty in every >> sample. To insure the co
Re: [time-nuts] Brooks Shera
Bob, You are preaching to the choir and although Brooks felt that using an XO and asynchronous gating to improve the resolution was sufficient and GPS sawtooth correction was not needed with the long averaging times in his controller that doesn't mean that I agreed. The early work I did just reduced the glitches and improved the resolution so there was sufficient gain for proper damping to discipline an atomic source. As I learned more the benefits of greater phase accuracy became apparent and led to the development of the IDC. The IDC uses the disciplined source as a stable timebase with PICTIC interpolation to increase the resolution. The typical interpolation gain is 400 for 62.5ps/sample resolution but this is reduced to 1ns to match the GPS resolution. The combined instabilities in the interpolator are below +/- 4 ADC counts so after the 16x reduction the 1ns phase data returned is accurate. The 1PPS stability has no effect on the 1ns TIC resolution so the accumulated phase data is accurate whether the 1PPS timing is varying or stationary. The data has the GPS sawtooth correction applied before filtering, so even if a 1PPS offset is present for an extended period during a hanging bridge the sawtooth corrected phase data entering the filter will be accurate. The only place in the IDC where the sawtooth is used to advantage is over a 2 hour calibration period there are typically enough min/max variations due to the GPS sawtooth to accurately determine the interpolator offset and span. Richard > Hi > > Using the GPS sawtooth as a source of randomness is dangerous. It can stop > moving > for minutes at a time if the conditions happen to be just right (or in this > case > wrong). Of course lack of randomization isn't your only problem when this > happens. > The (likely substantial) offset in the data is also a significant issue. > > Bob > > On Mar 25, 2013, at 8:35 PM, Bruce Griffiths > wrote: > >> Richard H McCorkle wrote: >>> Hi Tom, >>> >>> In the Shera design the instability of the XO timebase is >>> a key factor in improving the 30-second update resolution. >>> With the XO drift varying the sample point across the 1PPS >>> and 312.5 KHz edges the samples are constantly varying and >>> the average of the samples has a resolution much closer to >>> (1/CLK)/30 or 1.4ns. If both signals were synchronized >>> with the clock the start and stop edges of every sample >>> would fall exactly on a clock. In lock the odds of the >>> sources having a sample-to-sample variation greater than >>> 1 clock period (+/- 41.7ns) over the 30 second sample >>> period is low. So the probability is high that you would >>> get 30 identical samples with an average resolution much >>> closer to 41.7ns (+/- 1 clock). >>> >> The above assertion is not correct if the inputs to the synchroniser(s) are >> asynchronous to the synchroniser clock. >> The gate period will have a bounded (neglecting the effect of metastability >> at >> the output of the synchronisers) variation of +- 1 count. >> Provided that the synchroniser (and counter) clock and the divided down >> disciplined oscillator clock meet the conditions outlined by David Chu in: >> http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1974-06.pdf >> >> In practice these conditions may be difficult to meet without adequate random >> phase modulation of PPS (and the divided down disciplined oscillator signal). >> Alternatively phase modulating the synchroniser/counter clock is perhaps >> simpler. >> The sawtooth phase modulation of the PPS signal output produced by many >> timing >> GPS receivers isnt sufficiently random to be particularly useful. >>> The counter clock and asynchronous gate are applied to >>> an AND gate in the CD4520 that drives all 4 stages so when >>> an asynchronous gate edge and clock are coincident a short >>> clock pulse is generated and the setup and hold times of >>> the CD4520 counter are not met. Under these conditions the >>> first 4 stages in the 4520 could end up in an indeterminate >>> state and the input to the 4040 would be questionable. The >>> counter should settle to some value by the next clock, >>> but the value could be up to +/- 31 counts different than >>> it should be. Shera gates multiple samples into the >>> counter with a single read/reset per 30-second update so >>> multiple uncertainties can be introduced in the accumulated >>> count. >>> Recognizing the probability of asynchronous gating >>> resulting in glitches in the data Shera uses a de-glitch >>> routine in modes 4-7 that detects any 30-second value that >>> exceeds +/- 30 counts from the previous value as a glitch >>> and uses the previous value when this condition is detected. >>> This is far from ideal as multiple errors could be >>> accumulated with an average value less than +/- 30 counts >>> per update, but it does handle the occasional glitch when >>> the gate and XO edges are coincident and a>30 count error >>> results. The XO stability usually insures coi
Re: [time-nuts] Brooks Shera
Hi One very important thing to consider when looking at this design - it was done in the era of selective availability. That provided a lot dither all by it's self. Bob On Mar 25, 2013, at 10:05 PM, "Richard H McCorkle" wrote: > Bob, > You are preaching to the choir and although Brooks felt that > using an XO and asynchronous gating to improve the resolution > was sufficient and GPS sawtooth correction was not needed with > the long averaging times in his controller that doesn't mean > that I agreed. The early work I did just reduced the glitches > and improved the resolution so there was sufficient gain for > proper damping to discipline an atomic source. As I learned > more the benefits of greater phase accuracy became apparent > and led to the development of the IDC. > The IDC uses the disciplined source as a stable timebase with > PICTIC interpolation to increase the resolution. The typical > interpolation gain is 400 for 62.5ps/sample resolution but > this is reduced to 1ns to match the GPS resolution. The combined > instabilities in the interpolator are below +/- 4 ADC counts so > after the 16x reduction the 1ns phase data returned is accurate. > The 1PPS stability has no effect on the 1ns TIC resolution so > the accumulated phase data is accurate whether the 1PPS timing > is varying or stationary. The data has the GPS sawtooth correction > applied before filtering, so even if a 1PPS offset is present for > an extended period during a hanging bridge the sawtooth corrected > phase data entering the filter will be accurate. The only place in > the IDC where the sawtooth is used to advantage is over a 2 hour > calibration period there are typically enough min/max variations > due to the GPS sawtooth to accurately determine the interpolator > offset and span. > > Richard > > >> Hi >> >> Using the GPS sawtooth as a source of randomness is dangerous. It can stop >> moving >> for minutes at a time if the conditions happen to be just right (or in this >> case >> wrong). Of course lack of randomization isn't your only problem when this >> happens. >> The (likely substantial) offset in the data is also a significant issue. >> >> Bob >> >> On Mar 25, 2013, at 8:35 PM, Bruce Griffiths >> wrote: >> >>> Richard H McCorkle wrote: Hi Tom, In the Shera design the instability of the XO timebase is a key factor in improving the 30-second update resolution. With the XO drift varying the sample point across the 1PPS and 312.5 KHz edges the samples are constantly varying and the average of the samples has a resolution much closer to (1/CLK)/30 or 1.4ns. If both signals were synchronized with the clock the start and stop edges of every sample would fall exactly on a clock. In lock the odds of the sources having a sample-to-sample variation greater than 1 clock period (+/- 41.7ns) over the 30 second sample period is low. So the probability is high that you would get 30 identical samples with an average resolution much closer to 41.7ns (+/- 1 clock). >>> The above assertion is not correct if the inputs to the synchroniser(s) are >>> asynchronous to the synchroniser clock. >>> The gate period will have a bounded (neglecting the effect of metastability >>> at >>> the output of the synchronisers) variation of +- 1 count. >>> Provided that the synchroniser (and counter) clock and the divided down >>> disciplined oscillator clock meet the conditions outlined by David Chu in: >>> http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1974-06.pdf >>> >>> In practice these conditions may be difficult to meet without adequate >>> random >>> phase modulation of PPS (and the divided down disciplined oscillator >>> signal). >>> Alternatively phase modulating the synchroniser/counter clock is perhaps >>> simpler. >>> The sawtooth phase modulation of the PPS signal output produced by many >>> timing >>> GPS receivers isnt sufficiently random to be particularly useful. The counter clock and asynchronous gate are applied to an AND gate in the CD4520 that drives all 4 stages so when an asynchronous gate edge and clock are coincident a short clock pulse is generated and the setup and hold times of the CD4520 counter are not met. Under these conditions the first 4 stages in the 4520 could end up in an indeterminate state and the input to the 4040 would be questionable. The counter should settle to some value by the next clock, but the value could be up to +/- 31 counts different than it should be. Shera gates multiple samples into the counter with a single read/reset per 30-second update so multiple uncertainties can be introduced in the accumulated count. Recognizing the probability of asynchronous gating resulting in glitches in the data Shera uses a de-glitch routine in modes 4-7 that detects any 30-second value that exceeds +/- 30 counts from the previou
Re: [time-nuts] Brooks Shera
On 03/26/2013 01:35 AM, Bruce Griffiths wrote: Richard H McCorkle wrote: Hi Tom, In the Shera design the instability of the XO timebase is a key factor in improving the 30-second update resolution. With the XO drift varying the sample point across the 1PPS and 312.5 KHz edges the samples are constantly varying and the average of the samples has a resolution much closer to (1/CLK)/30 or 1.4ns. If both signals were synchronized with the clock the start and stop edges of every sample would fall exactly on a clock. In lock the odds of the sources having a sample-to-sample variation greater than 1 clock period (+/- 41.7ns) over the 30 second sample period is low. So the probability is high that you would get 30 identical samples with an average resolution much closer to 41.7ns (+/- 1 clock). The above assertion is not correct if the inputs to the synchroniser(s) are asynchronous to the synchroniser clock. The gate period will have a bounded (neglecting the effect of metastability at the output of the synchronisers) variation of +- 1 count. Provided that the synchroniser (and counter) clock and the divided down disciplined oscillator clock meet the conditions outlined by David Chu in: http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1974-06.pdf In practice these conditions may be difficult to meet without adequate random phase modulation of PPS (and the divided down disciplined oscillator signal). Alternatively phase modulating the synchroniser/counter clock is perhaps simpler. The sawtooth phase modulation of the PPS signal output produced by many timing GPS receivers isnt sufficiently random to be particularly useful. A variant of the modulation was used in the HP5328A with 040 option when doing T.I. averaging. As the 10 MHz time-base was PLLed to 100 MHz for increased singel-shot resolution, a noise source was added to the loop for averaging to make sure that the phase modulation smoothed the various phase-relationships between the clocks to produce meaningful averaging. As for PPS sawtooth, the trouble with that approach is that the clock generating the PPS isn't tuned to a suitable frequency for this form of beat-note averaging to always achieve the needed resolution, and the hanging bridge is when that beating has a "blind spot" and does not produce useful delta-information at sufficient rate. You can also have beating conditions causing many transitions, but few of these transitions carry any useful information, because it sweeps a too low set of phase-states to do any meaningfull averaging. I have considered writing something up on this topic, but have not come around to do it. Thanks for the reference Bruce! I've seen it, so it was a good reminder. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY I had an email reply from him a couple of months ago. Reply was less than 24 Hours. A couple of weeks ago I needed a PIC for his project and ended up programming it from the file I downloaded from his site. Biggest problem was finding the PIC as it is quite old. David At 11:07 AM 3/10/2007, you wrote: >I emailed Brooks about four weeks ago asking him if he could still supply >the programmed PICs as he volunteered when his article was first published. >I got no response, does anyone know of Brooks? > > >___ >time-nuts mailing list -- time-nuts@febo.com >To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >and follow the instructions there. > > > >-- >No virus found in this incoming message. >Checked by AVG Free Edition. >Version: 7.5.488 / Virus Database: 269.13.39/1045 - Release Date: >2/10/2007 6:43 PM David G. Hopkins (Vk4ZF) CAPALABA QLD. AUSTRALIA S27 32.191 E153 11.867 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.488 / Virus Database: 269.13.39/1045 - Release Date: 2/10/2007 6:43 PM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY David Hopkins wrote: > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] RETRY > > I had an email reply from him a couple of months ago. Reply was less > than 24 Hours. > > A couple of weeks ago I needed a PIC for his project and ended up > programming it from the file I downloaded from his site. > > Biggest problem was finding the PIC as it is quite old. > > David > > At 11:07 AM 3/10/2007, you wrote: > > Here in the US, it looks like Digikey still has the 16C73A available. Several newer chips would probably work fine, though, loading the Shera hex module, but telling the programmer what chip it is. A few chips that I think would be ok: 16F73, 16F873, 16F876. Looks like at least 10 MHz versions would be required for the input clock. Has anyone ever seen the commented assembler source? I would be interested to see how the filtering and math was implemented -- but I guess I am not interested enough to try to dig it out without comments and symbols. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY The source is at: http://www.leapsecond.com/pages/ppsdiv/?C=N;O=A Peter Lacey AA1ZU -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Rex Sent: Wednesday, October 03, 2007 5:35 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Brooks Shera David Hopkins wrote: > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] RETRY > > I had an email reply from him a couple of months ago. Reply was less > than 24 Hours. > > A couple of weeks ago I needed a PIC for his project and ended up > programming it from the file I downloaded from his site. > > Biggest problem was finding the PIC as it is quite old. > > David > > At 11:07 AM 3/10/2007, you wrote: > > Here in the US, it looks like Digikey still has the 16C73A available. Several newer chips would probably work fine, though, loading the Shera hex module, but telling the programmer what chip it is. A few chips that I think would be ok: 16F73, 16F873, 16F876. Looks like at least 10 MHz versions would be required for the input clock. Has anyone ever seen the commented assembler source? I would be interested to see how the filtering and math was implemented -- but I guess I am not interested enough to try to dig it out without comments and symbols. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Peter Lacey wrote: > The source is at: > > http://www.leapsecond.com/pages/ppsdiv/?C=N;O=A > > Peter Lacey > AA1ZU > > I have seen that code before. I believe that is simply a divider by TVB. The code I was asking about is the code Brooks Shera wrote for his GPS disciplined controller. It implements a lot more number crunching, I think. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Hi Peter: The code on that page is for the divider that Tom did in a PIC. It's not the Shera GPSDO. http://www.prc68.com/I/PRC68COM.shtml#TVB Have Fun, Brooke Clarke http://www.PRC68.com http://www.precisionclock.com http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Cam Peter Lacey wrote: > ); SAEximRunCond expanded to false > Errors-To: [EMAIL PROTECTED] RETRY > > The source is at: > > http://www.leapsecond.com/pages/ppsdiv/?C=N;O=A > > Peter Lacey > AA1ZU > > -Original Message- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On > Behalf Of Rex > Sent: Wednesday, October 03, 2007 5:35 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Brooks Shera > > David Hopkins wrote: > >>); SAEximRunCond expanded to false >>Errors-To: [EMAIL PROTECTED] RETRY >> >>I had an email reply from him a couple of months ago. Reply was less >>than 24 Hours. >> >>A couple of weeks ago I needed a PIC for his project and ended up >>programming it from the file I downloaded from his site. >> >>Biggest problem was finding the PIC as it is quite old. >> >>David >> >>At 11:07 AM 3/10/2007, you wrote: >> >> > > Here in the US, it looks like Digikey still has the 16C73A available. > Several newer chips would probably work fine, though, loading the Shera > hex module, but telling the programmer what chip it is. A few chips that > I think would be ok: 16F73, 16F873, 16F876. Looks like at least 10 MHz > versions would be required for the input clock. > > Has anyone ever seen the commented assembler source? I would be > interested to see how the filtering and math was implemented -- but I > guess I am not interested enough to try to dig it out without comments > and symbols. > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY > I have seen that code before. I believe that is simply a divider by TVB. > The code I was asking about is the code Brooks Shera wrote for his GPS > disciplined controller. It implements a lot more number crunching, I think. http://www.leapsecond.com/pages/ppsdiv/ppsdiv.asm Right, I wrote the one-chip PIC divider many years ago when the 16C84 was the PIC of choice. That was replaced with the 16F84A, and several more recent 16F6-series processors. Turn off the WDT when you flash the code. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera ASM release
Bert Thank you for working to share Brooks code with the time-nuts. Regards Paul. On Fri, Apr 12, 2013 at 2:28 PM, wrote: > > Attached is Brooks Shera’s final source code and hex file. As a reminder > in all of his released code Brooks requested that any use of his code be > limited to non-commercial applications. > > Users of this code implicitly agree to the following conditions: > > Copyright © 1997-2008, Brooks Shera. All rights reserved. This program > may be used only for non-commercial purposes, and carries no warranty > of any kind, including any implied warranty of fitness for any particular > purpose. > Redistribution and use in source and binary forms, with or without > modification, are permitted for non-commercial purposes only > provided that the following conditions are met: > > 1. Redistributions of source code must retain the above copyright > notice, this list of conditions and the following disclaimer. > > 2. Redistributions in binary form must reproduce the above copyright > notice, this list of conditions and the following disclaimer in the > documentation and/or other materials provided with the distribution. > > This software is provided by the author and contributors "as is" and > any express or implied warranties, including, but not limited to, the > implied warranties of merchantability and fitness for a particular > purpose are disclaimed. In no event shall the author or contributors > be liable for any direct, indirect, incidental, special, exemplary, > or consequential damages (including, but not limited to, procurement > of substitute goods or services; loss of use, data, or profits; or > business interruption) however caused and on any theory of liability, > whether in contract, strict liability, or tort (including negligence > or otherwise) arising in any way out of the use of this software, > even if advised of the possibility of such damage. > At this time I like to thank Brooks for all the work he did, his wife > Karen Stoll for deciding to release HEX and ASM and Bob Leichner who > implemented the software commands. Brooks did not have the chance to put > final > touches in and complete his work, so Richard McCorkle stepped in and made > the > final changes. For almost a decade Brooks and Richard collaborated on the > GPSDO, which benefits all of us. Also major recognition has to go to Juerg > Koegel an other time nut that put our other projects on hold to check every > iteration. Attached is part of a test that clearly shows the performance > of the > Alpha filter and AutoN. Limited by attachment size contact me off list for > more data. > The code supports 16C73, 16F73, 16F873A and 16F876A. > Juerg using the original A&A board with original components but a 16F876A > sees 5 E-12 after 12 hours. The data and Hex file is for 16F876A. Once > other Hex files have been tested they will be released. Any one can also > do > their own compellation using the attached ASM file. > > > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera ASM release
Gentlemen, this is a very good note, many thanks for this very interesting information and the work behind! I will try to implement the new code and a new processor without mistakes from my side. Regards, Arnold, DK2WT Am 12.04.2013 20:28, schrieb ewkeh...@aol.com: > > Attached is Brooks Shera's final source code and hex file. As a reminder > in all of his released code Brooks requested that any use of his code be > limited to non-commercial applications. > > Users of this code implicitly agree to the following conditions: > > Copyright © 1997-2008, Brooks Shera. All rights reserved. This program > may be used only for non-commercial purposes, and carries no warranty > of any kind, including any implied warranty of fitness for any particular > purpose. > Redistribution and use in source and binary forms, with or without > modification, are permitted for non-commercial purposes only > provided that the following conditions are met: > > 1. Redistributions of source code must retain the above copyright > notice, this list of conditions and the following disclaimer. > > 2. Redistributions in binary form must reproduce the above copyright > notice, this list of conditions and the following disclaimer in the > documentation and/or other materials provided with the distribution. > > This software is provided by the author and contributors "as is" and > any express or implied warranties, including, but not limited to, the > implied warranties of merchantability and fitness for a particular > purpose are disclaimed. In no event shall the author or contributors > be liable for any direct, indirect, incidental, special, exemplary, > or consequential damages (including, but not limited to, procurement > of substitute goods or services; loss of use, data, or profits; or > business interruption) however caused and on any theory of liability, > whether in contract, strict liability, or tort (including negligence > or otherwise) arising in any way out of the use of this software, > even if advised of the possibility of such damage. > At this time I like to thank Brooks for all the work he did, his wife > Karen Stoll for deciding to release HEX and ASM and Bob Leichner who > implemented the software commands. Brooks did not have the chance to put > final > touches in and complete his work, so Richard McCorkle stepped in and made > the > final changes. For almost a decade Brooks and Richard collaborated on the > GPSDO, which benefits all of us. Also major recognition has to go to Juerg > Koegel an other time nut that put our other projects on hold to check every > iteration. Attached is part of a test that clearly shows the performance of > the > Alpha filter and AutoN. Limited by attachment size contact me off list for > more data. > The code supports 16C73, 16F73, 16F873A and 16F876A. > Juerg using the original A&A board with original components but a 16F876A > sees 5 E-12 after 12 hours. The data and Hex file is for 16F876A. Once > other Hex files have been tested they will be released. Any one can also do > their own compellation using the attached ASM file. > > > > > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera ASM release
Bert is there any way we can add our names to some expression of thanks to his widow Karen and her helpers for their work and maybe leave a remembrance of his worldwide friends for his family? Thanks for your efforts Best wishes Alan Melia (G3NYK) UK - Original Message - From: To: Sent: Friday, April 12, 2013 8:52 PM Subject: [time-nuts] Brooks Shera ASM release The time-nuts server takes out all spaces so allow me to resend the acknowledgementsBert Kehren At this time I like to thank Brooks for all the work he did, his wife Karen Stoll for deciding to release HEX and ASM and Bob Leichner who implemented the software commands. Brooks did not have the chance to put final touches in and complete his work, so Richard McCorkle stepped in and made the final changes. For almost a decade Brooks and Richard collaborated on the GPSDO, which benefits all of us. Also major recognition has to go to Juerg Koegel an other time nut that put our other projects on hold to check every iteration. Attached is part of a test that clearly shows the performance of the Alpha filter. Limited by attachment size contact me off list for more data. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera ASM release
Alan You may suggest something to time nuts, looking at the response I doubt it and ask my self why did three of us spend three weeks to fully check it out and fix some of the code. Will reflect future projects. Bert Kehren In a message dated 4/12/2013 8:39:40 P.M. Eastern Daylight Time, alan.me...@btinternet.com writes: Bert is there any way we can add our names to some expression of thanks to his widow Karen and her helpers for their work and maybe leave a remembrance of his worldwide friends for his family? Thanks for your efforts Best wishes Alan Melia (G3NYK) UK - Original Message - From: To: Sent: Friday, April 12, 2013 8:52 PM Subject: [time-nuts] Brooks Shera ASM release > The time-nuts server takes out all spaces so allow me to resend the > acknowledgementsBert Kehren > > > > > At this time I like to thank Brooks for all the work he did, his wife > Karen Stoll for deciding to release HEX and ASM and Bob Leichner who > implemented the software commands. Brooks did not have the chance to put > final > touches in and complete his work, so Richard McCorkle stepped in and made > the > final changes. For almost a decade Brooks and Richard collaborated on the > GPSDO, which benefits all of us. Also major recognition has to go to > Juerg > Koegel an other time nut that put our other projects on hold to check > every > iteration. Attached is part of a test that clearly shows the performance > of > the Alpha filter. Limited by attachment size contact me off list for more > data. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera ASM release
Hi Bert, Just because there was not much response to this inquiry does not mean that your efforts are not appreciated. Considering how many requested the earlier code (many in person to myself) I expect your work is VERY MUCH appreciated. Thank you, David On 4/15/13 3:17 PM, ewkeh...@aol.com wrote: Alan You may suggest something to time nuts, looking at the response I doubt it and ask my self why did three of us spend three weeks to fully check it out and fix some of the code. Will reflect future projects. Bert Kehren In a message dated 4/12/2013 8:39:40 P.M. Eastern Daylight Time, alan.me...@btinternet.com writes: Bert is there any way we can add our names to some expression of thanks to his widow Karen and her helpers for their work and maybe leave a remembrance of his worldwide friends for his family? Thanks for your efforts Best wishes Alan Melia (G3NYK) UK - Original Message - From: To: Sent: Friday, April 12, 2013 8:52 PM Subject: [time-nuts] Brooks Shera ASM release The time-nuts server takes out all spaces so allow me to resend the acknowledgementsBert Kehren At this time I like to thank Brooks for all the work he did, his wife Karen Stoll for deciding to release HEX and ASM and Bob Leichner who implemented the software commands. Brooks did not have the chance to put final touches in and complete his work, so Richard McCorkle stepped in and made the final changes. For almost a decade Brooks and Richard collaborated on the GPSDO, which benefits all of us. Also major recognition has to go to Juerg Koegel an other time nut that put our other projects on hold to check every iteration. Attached is part of a test that clearly shows the performance of the Alpha filter. Limited by attachment size contact me off list for more data. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera ASM release
On 04/15/2013 10:00 PM, David McGaw wrote: Hi Bert, Just because there was not much response to this inquiry does not mean that your efforts are not appreciated. Considering how many requested the earlier code (many in person to myself) I expect your work is VERY MUCH appreciated. I for one apprechiate the effort. Will look it through. See what he did and what there is to be learned. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera ASM release
Hi Bert, I do fully support David's opinion, I appreciate very much all the past and future work on this subject like all other developments in the group, so please don't stop, it made me happy when I got the code list in your past mail! Thank you very much, regards, Arnold, DK2WT am 15.04.2013 22:00, schrieb David McGaw: > Hi Bert, > > Just because there was not much response to this inquiry does not mean > that your efforts are not appreciated. Considering how many requested > the earlier code (many in person to myself) I expect your work is VERY > MUCH appreciated. > > Thank you, > > David > > > On 4/15/13 3:17 PM, ewkeh...@aol.com wrote: >> Alan >> You may suggest something to time nuts, looking at the response I >> doubt it >> and ask my self why did three of us spend three weeks to fully check >> it out >> and fix some of the code. Will reflect future projects. >> Bert Kehren >> In a message dated 4/12/2013 8:39:40 P.M. Eastern Daylight Time, >> alan.me...@btinternet.com writes: >> >> Bert is there any way we can add our names to some expression of >> thanks to >> his widow Karen and her helpers for their work and maybe leave a >> remembrance >> of his worldwide friends for his family? >> >> Thanks for your efforts >> Best wishes >> Alan Melia (G3NYK) >> UK >> >> >> - Original Message - >> From: >> To: >> Sent: Friday, April 12, 2013 8:52 PM >> Subject: [time-nuts] Brooks Shera ASM release >> >> >>> The time-nuts server takes out all spaces so allow me to resend the >>> acknowledgementsBert Kehren >>> >>> >>> >>> >>> At this time I like to thank Brooks for all the work he did, his wife >>> Karen Stoll for deciding to release HEX and ASM and Bob Leichner who >>> implemented the software commands. Brooks did not have the chance to >> put >>> final >>> touches in and complete his work, so Richard McCorkle stepped in and >> made >>> the >>> final changes. For almost a decade Brooks and Richard collaborated on >> the >>> GPSDO, which benefits all of us. Also major recognition has to go to >>> Juerg >>> Koegel an other time nut that put our other projects on hold to check >>> every >>> iteration. Attached is part of a test that clearly shows the >> performance >>> of >>> the Alpha filter. Limited by attachment size contact me off list for >> more >>> data. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera ASM release
Ok Bert I will stick my head above the parapet and repeat that query.Sometimes it is frustarting the get no response, but later get personal appreciation as you meet individuals. I didn't know the guy. I was trying with a friend to contact him long after the original article. We were disapointed but not unhappy. I certainly appreciate the help and expertise the Group provides..and it is nice to be able to say so, and salute the work Brooks did. Thanks and Best Wishes Alan Melia (G3NYK) - Original Message - From: To: Sent: Monday, April 15, 2013 8:17 PM Subject: Re: [time-nuts] Brooks Shera ASM release Alan You may suggest something to time nuts, looking at the response I doubt it and ask my self why did three of us spend three weeks to fully check it out and fix some of the code. Will reflect future projects. Bert Kehren In a message dated 4/12/2013 8:39:40 P.M. Eastern Daylight Time, alan.me...@btinternet.com writes: Bert is there any way we can add our names to some expression of thanks to his widow Karen and her helpers for their work and maybe leave a remembrance of his worldwide friends for his family? Thanks for your efforts Best wishes Alan Melia (G3NYK) UK - Original Message - From: To: Sent: Friday, April 12, 2013 8:52 PM Subject: [time-nuts] Brooks Shera ASM release The time-nuts server takes out all spaces so allow me to resend the acknowledgementsBert Kehren At this time I like to thank Brooks for all the work he did, his wife Karen Stoll for deciding to release HEX and ASM and Bob Leichner who implemented the software commands. Brooks did not have the chance to put final touches in and complete his work, so Richard McCorkle stepped in and made the final changes. For almost a decade Brooks and Richard collaborated on the GPSDO, which benefits all of us. Also major recognition has to go to Juerg Koegel an other time nut that put our other projects on hold to check every iteration. Attached is part of a test that clearly shows the performance of the Alpha filter. Limited by attachment size contact me off list for more data. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera ASM release
Bert I am grateful for the work you and friends have done. Is there any way we can add our names to some expression of thanks from members of the Group to his widow Karen and her helpers for their work in making the checked source code for the GPSDO available to us and maybe leave a token of remembrance of his worldwide friends, for his family? Even if it is just a "me too" replying to this message. Alan Melia (G3NYK) Ipswich, UK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera thanks options
The online obit at http://www.santafefuneraloption.com/sitemaker/sites/santaf0/obit.cgi?user=949646Shera says, "Memorials may be made to the University of Chicago Laboratory Schools, the Sierra Club, or any organization of the Donor’s choice." University of Chicago Laboratory Schools http://www.ucls.uchicago.edu/ (look under 'Support Lab' for contribution links) Sierra Club http://www.sierraclub.org/ (big orange "DONATE" button) I don't see a PayPal option on either one. Chris W0EP On 4/15/2013 6:29 PM, Alan Melia wrote: > Ok Bert I will stick my head above the parapet and repeat that > query.Sometimes it is frustarting the get no response, but later get personal > appreciation as you meet individuals. I didn't know the guy. I was trying > with a friend to contact him long after the original article. We were > disapointed but not unhappy. I certainly appreciate the help and expertise > the Group provides..and it is nice to be able to say so, and salute the > work Brooks did. > > Thanks and Best Wishes > Alan Melia > (G3NYK) > - Original Message ----- From: > To: > Sent: Monday, April 15, 2013 8:17 PM > Subject: Re: [time-nuts] Brooks Shera ASM release > > >> Alan >> You may suggest something to time nuts, looking at the response I doubt it >> and ask my self why did three of us spend three weeks to fully check it out >> and fix some of the code. Will reflect future projects. >> Bert Kehren >> >> >> In a message dated 4/12/2013 8:39:40 P.M. Eastern Daylight Time, >> alan.me...@btinternet.com writes: >> >> Bert is there any way we can add our names to some expression of thanks to >> his widow Karen and her helpers for their work and maybe leave a >> remembrance >> of his worldwide friends for his family? >> >> Thanks for your efforts >> Best wishes >> Alan Melia (G3NYK) >> UK >> >> >> - Original Message - From: >> To: >> Sent: Friday, April 12, 2013 8:52 PM >> Subject: [time-nuts] Brooks Shera ASM release >> >> >>> The time-nuts server takes out all spaces so allow me to resend the >>> acknowledgementsBert Kehren >>> >>> >>> >>> >>> At this time I like to thank Brooks for all the work he did, his wife >>> Karen Stoll for deciding to release HEX and ASM and Bob Leichner who >>> implemented the software commands. Brooks did not have the chance to >> put >>> final >>> touches in and complete his work, so Richard McCorkle stepped in and >> made >>> the >>> final changes. For almost a decade Brooks and Richard collaborated on >> the >>> GPSDO, which benefits all of us. Also major recognition has to go to >>> Juerg >>> Koegel an other time nut that put our other projects on hold to check >>> every >>> iteration. Attached is part of a test that clearly shows the >> performance >>> of >>> the Alpha filter. Limited by attachment size contact me off list for >> more >>> data. >>> ___ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera ASM release
Bert, As one of Brooks "customers" I would like to express my thanks to him for his generous work (fortunately I did it when we contacted in early 2009), and also now to thank you and the others who made possible to finally have his code, including the efforts to fix and test it. And of course thank his widow for letting this to happen. I was traveling abroad when you posted the code and intermediately downloaded and secured it while at the airport. Back home now it is the time to say thank you all. Best regards, Ignacio EB4APL On 15/04/2013 21:17, ewkeh...@aol.com wrote: Alan You may suggest something to time nuts, looking at the response I doubt it and ask my self why did three of us spend three weeks to fully check it out and fix some of the code. Will reflect future projects. Bert Kehren In a message dated 4/12/2013 8:39:40 P.M. Eastern Daylight Time, alan.me...@btinternet.com writes: Bert is there any way we can add our names to some expression of thanks to his widow Karen and her helpers for their work and maybe leave a remembrance of his worldwide friends for his family? Thanks for your efforts Best wishes Alan Melia (G3NYK) UK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera ASM release
Me too, Didn't say anything before to keep the noise down. Robert G8RPI. From: Alan Melia To: time-nuts measurement Sent: Tuesday, 16 April 2013, 0:40 Subject: Re: [time-nuts] Brooks Shera ASM release Bert I am grateful for the work you and friends have done. Is there any way we can add our names to some expression of thanks from members of the Group to his widow Karen and her helpers for their work in making the checked source code for the GPSDO available to us and maybe leave a token of remembrance of his worldwide friends, for his family? Even if it is just a "me too" replying to this message. Alan Melia (G3NYK) Ipswich, UK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera ASM release
Bert, I certainly appreciate all the work that has gone into the latest code. I learnt a lot from Brook's original (1.33) and modified it to suit my 'peculiar' hardware. I've only had time for a short look at the latest but I'm sure there is MUCH to learn here too. A very well written program with good commenting - not often seen nowadays. Many thanks to all involved. regards, Paul Reeves G8GJA -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ewkeh...@aol.com Sent: 15 April 2013 20:18 To: time-nuts@febo.com Subject: Re: [time-nuts] Brooks Shera ASM release Alan You may suggest something to time nuts, looking at the response I doubt it and ask my self why did three of us spend three weeks to fully check it out and fix some of the code. Will reflect future projects. Bert Kehren In a message dated 4/12/2013 8:39:40 P.M. Eastern Daylight Time, alan.me...@btinternet.com writes: Bert is there any way we can add our names to some expression of thanks to his widow Karen and her helpers for their work and maybe leave a remembrance of his worldwide friends for his family? Thanks for your efforts Best wishes Alan Melia (G3NYK) UK - Original Message - From: To: Sent: Friday, April 12, 2013 8:52 PM Subject: [time-nuts] Brooks Shera ASM release > The time-nuts server takes out all spaces so allow me to resend the > acknowledgementsBert Kehren > > > > > At this time I like to thank Brooks for all the work he did, his wife > Karen Stoll for deciding to release HEX and ASM and Bob Leichner who > implemented the software commands. Brooks did not have the chance to put > final > touches in and complete his work, so Richard McCorkle stepped in and made > the > final changes. For almost a decade Brooks and Richard collaborated on the > GPSDO, which benefits all of us. Also major recognition has to go to > Juerg > Koegel an other time nut that put our other projects on hold to check > every > iteration. Attached is part of a test that clearly shows the performance > of > the Alpha filter. Limited by attachment size contact me off list for more > data. > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera ASM release
Hmmm, apostrophe slip - apologies to any grammar-nuts amongst the time-nuts.. regards, Paul R -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of REEVES Paul Sent: 16 April 2013 08:07 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Brooks Shera ASM release Bert, I certainly appreciate all the work that has gone into the latest code. I learnt a lot from Brook's original (1.33) and modified it to suit my 'peculiar' hardware. I've only had time for a short look at the latest but I'm sure there is MUCH to learn here too. A very well written program with good commenting - not often seen nowadays. Many thanks to all involved. regards, Paul Reeves G8GJA >-Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ewkeh...@aol.com Sent: 15 April 2013 20:18 To: time-nuts@febo.com Subject: Re: [time-nuts] Brooks Shera ASM release >Alan You may suggest something to time nuts, looking at the response I doubt it and ask my self why did three of us spend three weeks to fully check it out and fix some of the code. Will reflect future projects. Bert Kehren >In a message dated 4/12/2013 8:39:40 P.M. Eastern Daylight Time, alan.me...@btinternet.com writes: >Bert is there any way we can add our names to some expression of thanks to his widow Karen and her helpers for their work and maybe leave a remembrance of his worldwide friends for his family? >Thanks for your efforts Best wishes Alan Melia (G3NYK) UK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Brooks Shera GPS Controller Help
First, take your OXCO, heat it up, and use just a pot for the 0 to 6 volt control range. Find out what control voltage is needed for the proper frequency. The DAC can't achieve lock if it can't reach that voltage. If that's all OK - the DAC output is within range - then find out what AC input voltage is required from the OXCO to the board. 0.4 volts sounds really low. What's all this about resistors? You can't achieve lock if the board has no input from the OXCO. Are you sure the GPS input is OK? Did that help? Bill Hawkins -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jason Rabel Sent: Monday, January 15, 2007 4:28 PM To: 'Discussion of precise time and frequency measurement' Subject: [time-nuts] Brooks Shera GPS Controller Help You guys might have noticed a little bit I posted in another topic, but I figured it's time I started my own now that I have the setup all hooked back up and running again. I'm having trouble getting the controller to lock the OCXO. The phase reading only goes between about 10 - 155... Nowhere near the 800 that means it is locked on. :( I have a Brandywine GPSDO that I used to coarse adjust the 5 MHz (both hooked into my oscope), and I got it spot-on, probably way more than necessary. I flip the Shera board to Mode 1, and the DAC voltage jumps to about 1V and goes up and down between that and about 1.1V, slowly back and forth. If I switch to Mode 2 or higher, then the DAC voltage will go all the way through its -3V to +3V range, when it hits the top of the +3V it jumps down to -3V and works its way up again. I'm using the A&A board, all my solder joints are good, even the couple that were the least bit questionable I fixed just to be 100% sure about that. I'm using a 5 MHz OCXO, with a tuning range between 0V to 6V. I have S4 closed, as my voltage increases the frequency decreases. On the A&A board I have pins 1 & 2 jumpered together on P3. The GPS is a Motorola Oncore VP, going through the TTL in. The OCXO is going through the AC coupled input, after the resistors its still showing about .4V p-p. Just the plain output is about 2.5-3V p-p, I *think* I could just use the TTL in then? The notes says about 2V or less so that's what I have it going through the resistors. The first LED always stays lit signifying that the lock is questionable (obviously). My coarse adjust is a 10K pot, I did just add a 2K pot inline as a fine adjust, but have not re-calculated the R5 & R6 values. It is acting exactly as before so I don't think that is the cause. But tomorrow I'll probably re-do the calculations for S, then also R5 & R6... My only guess is that something is wrong with the 5 MHz signal somewhere... The way the DAC voltage cycles makes me think it is just completely ignoring something. If anyone is interested in the raw phase data, email me directly and I can send them to you, but I don't know how helpful they will be. Jason ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Brooks Shera GPS Controller Help
Yep, I leave the OCXO always on since I finished that circuit. The OCXO outputs a 6V reference, from there I go to the 10K pot, which goes to the EFC and ground/DAC (I have it wired so I can use a jumper to ground when not hooked to the DAC. The 5 MHz target is achieved around like 3.2-3.3V, so it's still pretty well centered, I don't remember how much pull the DAC has going up or down, but that part is okay I know because I've watched the EFC voltage and frequency on the scope. I was talking about the resistors at P2 (R1 & R2). I think I can just use the TTL input instead of the AC coupled one. GPS is okay, it's a Motorola Oncore VP in fixed location mode. I also used a UT+ for a while before moving that to something else. Jason > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Bill Hawkins > Sent: Monday, January 15, 2007 6:58 PM > To: 'Discussion of precise time and frequency measurement' > Subject: Re: [time-nuts] Brooks Shera GPS Controller Help > > First, take your OXCO, heat it up, and use just a pot for the 0 to 6 > volt control range. Find out what control voltage is needed for the > proper frequency. The DAC can't achieve lock if it can't reach that > voltage. > > If that's all OK - the DAC output is within range - then find out what > AC input voltage is required from the OXCO to the board. 0.4 volts > sounds really low. What's all this about resistors? You can't achieve > lock if the board has no input from the OXCO. Are you sure > the GPS input > is OK? > > Did that help? > > Bill Hawkins > > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On > Behalf Of Jason Rabel > Sent: Monday, January 15, 2007 4:28 PM > To: 'Discussion of precise time and frequency measurement' > Subject: [time-nuts] Brooks Shera GPS Controller Help > > You guys might have noticed a little bit I posted in another > topic, but > I figured it's time I started my own now that I have the setup all > hooked back up and running again. > > I'm having trouble getting the controller to lock the OCXO. The phase > reading only goes between about 10 - 155... Nowhere near the 800 that > means it is locked on. :( > > I have a Brandywine GPSDO that I used to coarse adjust the 5 MHz (both > hooked into my oscope), and I got it spot-on, probably way more than > necessary. I flip the Shera board to Mode 1, and the DAC voltage jumps > to about 1V and goes up and down between that and about 1.1V, slowly > back and forth. > > If I switch to Mode 2 or higher, then the DAC voltage will go all the > way through its -3V to +3V range, when it hits the top of the +3V it > jumps down to -3V and works its way up again. > > I'm using the A&A board, all my solder joints are good, even > the couple > that were the least bit questionable I fixed just to be 100% > sure about > that. > > I'm using a 5 MHz OCXO, with a tuning range between 0V to 6V. > I have S4 > closed, as my voltage increases the frequency decreases. On the A&A > board I have pins 1 & 2 jumpered together on P3. The GPS is a Motorola > Oncore VP, going through the TTL in. The OCXO is going through the AC > coupled input, after the resistors its still showing about > .4V p-p. Just > the plain output is about 2.5-3V p-p, I *think* I could just > use the TTL > in then? The notes says about 2V or less so that's what I > have it going > through the resistors. > > The first LED always stays lit signifying that the lock is > questionable > (obviously). > > My coarse adjust is a 10K pot, I did just add a 2K pot inline > as a fine > adjust, but have not re-calculated the R5 & R6 values. It is acting > exactly as before so I don't think that is the cause. But > tomorrow I'll > probably re-do the calculations for S, then also R5 & R6... > > My only guess is that something is wrong with the 5 MHz signal > somewhere... > The way the DAC voltage cycles makes me think it is just completely > ignoring something. > > If anyone is interested in the raw phase data, email me directly and I > can send them to you, but I don't know how helpful they will be. > > Jason > > > > ___ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Brooks Shera GPS Controller Help
Hi Jason: 1)The oscillator needs to go into the VCXO In jack and then if you look at U1-2 (same as U2-1) you should see a zero to +5 square wave at the frequency of you oscillator. 2)The GPS 1 PPS goes into GPS In and of you look at U3-15 you should see a zero to +5 pulse once per second. If (1) and (2) above are correct then the inputs are OK. Do you know what the control voltage right at the input pin of the VCXO should be when you are locked? (3) Measure the voltage at the input pin with a scope while the Controller is ramping to see if it goes past the required voltage. Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Jason Rabel wrote: >Yep, I leave the OCXO always on since I finished that circuit. > >The OCXO outputs a 6V reference, from there I go to the 10K pot, which goes >to the EFC and ground/DAC (I have it wired so I can use a jumper to ground >when not hooked to the DAC. The 5 MHz target is achieved around like >3.2-3.3V, so it's still pretty well centered, I don't remember how much pull >the DAC has going up or down, but that part is okay I know because I've >watched the EFC voltage and frequency on the scope. > >I was talking about the resistors at P2 (R1 & R2). I think I can just use >the TTL input instead of the AC coupled one. > >GPS is okay, it's a Motorola Oncore VP in fixed location mode. I also used a >UT+ for a while before moving that to something else. > >Jason > > > >>-Original Message- >>From: [EMAIL PROTECTED] >>[mailto:[EMAIL PROTECTED] On Behalf Of Bill Hawkins >>Sent: Monday, January 15, 2007 6:58 PM >>To: 'Discussion of precise time and frequency measurement' >>Subject: Re: [time-nuts] Brooks Shera GPS Controller Help >> >>First, take your OXCO, heat it up, and use just a pot for the 0 to 6 >>volt control range. Find out what control voltage is needed for the >>proper frequency. The DAC can't achieve lock if it can't reach that >>voltage. >> >>If that's all OK - the DAC output is within range - then find out what >>AC input voltage is required from the OXCO to the board. 0.4 volts >>sounds really low. What's all this about resistors? You can't achieve >>lock if the board has no input from the OXCO. Are you sure >>the GPS input >>is OK? >> >>Did that help? >> >>Bill Hawkins >> >> >>-Original Message- >>From: [EMAIL PROTECTED] >>[mailto:[EMAIL PROTECTED] On >>Behalf Of Jason Rabel >>Sent: Monday, January 15, 2007 4:28 PM >>To: 'Discussion of precise time and frequency measurement' >>Subject: [time-nuts] Brooks Shera GPS Controller Help >> >>You guys might have noticed a little bit I posted in another >>topic, but >>I figured it's time I started my own now that I have the setup all >>hooked back up and running again. >> >>I'm having trouble getting the controller to lock the OCXO. The phase >>reading only goes between about 10 - 155... Nowhere near the 800 that >>means it is locked on. :( >> >>I have a Brandywine GPSDO that I used to coarse adjust the 5 MHz (both >>hooked into my oscope), and I got it spot-on, probably way more than >>necessary. I flip the Shera board to Mode 1, and the DAC voltage jumps >>to about 1V and goes up and down between that and about 1.1V, slowly >>back and forth. >> >>If I switch to Mode 2 or higher, then the DAC voltage will go all the >>way through its -3V to +3V range, when it hits the top of the +3V it >>jumps down to -3V and works its way up again. >> >>I'm using the A&A board, all my solder joints are good, even >>the couple >>that were the least bit questionable I fixed just to be 100% >>sure about >>that. >> >>I'm using a 5 MHz OCXO, with a tuning range between 0V to 6V. >>I have S4 >>closed, as my voltage increases the frequency decreases. On the A&A >>board I have pins 1 & 2 jumpered together on P3. The GPS is a Motorola >>Oncore VP, going through the TTL in. The OCXO is going through the AC >>coupled input, after the resistors its still showing about >>.4V p-p. Just >>the plain output is about 2.5-3V p-p, I *think* I could just >>use the TTL >>in then? The notes says about 2V or less so that's what I >>have it going >>through the resistors. >> >>The first LED always stays lit signifying that the lock is >>questionable >>(obviously). >> >>
Re: [time-nuts] Brooks Shera GPS Controller Help
Jason, What divider output are you using? The typical input to the phase detector should be between 312.5KHz and 625KHz and an appropriate jumper has to be installed on the divider header on the [EMAIL PROTECTED] board to tie the selected divider output to the phase detector. Sounds like you aren't getting a good clock into the phase counter reset. Hope this helps, Richard - Original Message - From: "Jason Rabel" <[EMAIL PROTECTED]> To: "'Discussion of precise time and frequency measurement'" Sent: Monday, January 15, 2007 1:28 PM Subject: [time-nuts] Brooks Shera GPS Controller Help > You guys might have noticed a little bit I posted in another topic, but I > figured it's time I started my own now that I have the setup all hooked back > up and running again. > > I'm having trouble getting the controller to lock the OCXO. The phase > reading only goes between about 10 - 155... Nowhere near the 800 that means > it is locked on. :( > > I have a Brandywine GPSDO that I used to coarse adjust the 5 MHz (both > hooked into my oscope), and I got it spot-on, probably way more than > necessary. I flip the Shera board to Mode 1, and the DAC voltage jumps to > about 1V and goes up and down between that and about 1.1V, slowly back and > forth. > > If I switch to Mode 2 or higher, then the DAC voltage will go all the way > through its -3V to +3V range, when it hits the top of the +3V it jumps down > to -3V and works its way up again. > > I'm using the A&A board, all my solder joints are good, even the couple that > were the least bit questionable I fixed just to be 100% sure about that. > > I'm using a 5 MHz OCXO, with a tuning range between 0V to 6V. I have S4 > closed, as my voltage increases the frequency decreases. On the A&A board I > have pins 1 & 2 jumpered together on P3. The GPS is a Motorola Oncore VP, > going through the TTL in. The OCXO is going through the AC coupled input, > after the resistors its still showing about .4V p-p. Just the plain output > is about 2.5-3V p-p, I *think* I could just use the TTL in then? The notes > says about 2V or less so that's what I have it going through the resistors. > > The first LED always stays lit signifying that the lock is questionable > (obviously). > > My coarse adjust is a 10K pot, I did just add a 2K pot inline as a fine > adjust, but have not re-calculated the R5 & R6 values. It is acting exactly > as before so I don't think that is the cause. But tomorrow I'll probably > re-do the calculations for S, then also R5 & R6... > > My only guess is that something is wrong with the 5 MHz signal somewhere... > The way the DAC voltage cycles makes me think it is just completely ignoring > something. > > If anyone is interested in the raw phase data, email me directly and I can > send them to you, but I don't know how helpful they will be. > > Jason > > > ___ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Brooks Shera GPS Controller Help
Checked that today, getting 315.5KHz (A&A Board - P3 pins 1&2 jumpered). I pulled all the chips, just to make sure I didn't have any bent/broken pins. Reflowed every pin on the board so there would be no doubt in my mind that there were any bad joints. Replaced chips Same problem I've been having. I just checked my frequency bits again, the full range on the OCXO EFC from 0-6V gives me 4,999,997.9 to 5,000,002.4 Hz (4.5 Hz total difference). Each volt shifts about .75 Hz (I measured from one volt to the next, but also just the simple division from the numbers I gave results in the same final number). It's like it's not counting or detecting the phase properly or something. Maybe one of my chips is the incorrect model? Here's a list for everyone to compare theirs to. U1&U3: TI CD74HC4046AE U2:ST M74HC4520B1 U5&U6: ST M74HC166B1 U4:TI CD74HCT4040E U7:EXO 35M / 24.000M / KSS JAPAN The PIC & DAC I got from Brooks, U10 is the Max233 (and not really related to the rest of the circuit). 5:00 now, time to go home... Jason > Jason, > What divider output are you using? The typical input to the > phase detector > should be between 312.5KHz and 625KHz and an appropriate > jumper has to be > installed on the divider header on the [EMAIL PROTECTED] board to tie the > selected divider > output to the phase detector. Sounds like you aren't getting > a good clock > into the phase counter reset. > Hope this helps, > Richard ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Brooks Shera GPS Controller Help
Here http://www.rt66.com/~shera/setup_notes.html In the troubleshooting section there's a note about A mysterious problem. I had this issue, I Wonder could it be related to your issue? In any case the fix does not hurt so worth a try? On Wed, 2007-01-17 at 17:05 -0600, Jason Rabel wrote: > Checked that today, getting 315.5KHz (A&A Board - P3 pins 1&2 jumpered). > > I pulled all the chips, just to make sure I didn't have any bent/broken > pins. Reflowed every pin on the board so there would be no doubt in my mind > that there were any bad joints. Replaced chips Same problem I've been > having. > > I just checked my frequency bits again, the full range on the OCXO EFC from > 0-6V gives me 4,999,997.9 to 5,000,002.4 Hz (4.5 Hz total difference). Each > volt shifts about .75 Hz (I measured from one volt to the next, but also > just the simple division from the numbers I gave results in the same final > number). > > It's like it's not counting or detecting the phase properly or something. > Maybe one of my chips is the incorrect model? Here's a list for everyone to > compare theirs to. > > U1&U3: TI CD74HC4046AE > U2:ST M74HC4520B1 > U5&U6: ST M74HC166B1 > U4:TI CD74HCT4040E > U7:EXO 35M / 24.000M / KSS JAPAN > > The PIC & DAC I got from Brooks, U10 is the Max233 (and not really related > to the rest of the circuit). > > 5:00 now, time to go home... > > Jason > > > Jason, > > What divider output are you using? The typical input to the > > phase detector > > should be between 312.5KHz and 625KHz and an appropriate > > jumper has to be > > installed on the divider header on the [EMAIL PROTECTED] board to tie the > > selected divider > > output to the phase detector. Sounds like you aren't getting > > a good clock > > into the phase counter reset. > > Hope this helps, > > Richard > > > ___ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Brooks Shera GPS Controller Help
Checked both U1-2 & U2-1, I am getting the 5 MHz / 0 to 5V square wave. It's not the nicest looking, but my counter reads it fine. Maybe this could be a problem? http://www.rabel.org/archives/Images/Misc/5MHz_Square.jpg Yes, U3-15 has the GPS PPS pulse, I can't see it on my scope but I can see the trigger light every second. Also if I unplug the GPS input then the board goes haywire. We are talking about the PPS pulse going from 0V rising to ~5V for the ttl in, correct? (just making sure it's not supposed to be inverted or some other weird thing, I'll try anything at this point.) The EFC voltage is about 3.35V or so when I adjust it to my other GPSDO reference. As soon as I flip from mode 0 to mode 1, the voltage will jump to around 1.1V and go up and down in that range, the EFC jumps to about 3.42V. This throws the frequency off noticeably, I've even tried to re-center the frequency while it's in mode 1 (but nothing different really happens). The phase reading never rises above ~155. It will reach that then fall back to about 10 and work its way slowly back up. I'm stumped... Jason > Hi Jason: > > 1)The oscillator needs to go into the VCXO In jack and > then if you > look at U1-2 (same as U2-1) you should see a zero to +5 > square wave at > the frequency of you oscillator. > > 2)The GPS 1 PPS goes into GPS In and of you look at U3-15 you > should see a zero to +5 pulse once per second. > > If (1) and (2) above are correct then the inputs are OK. > > Do you know what the control voltage right at the input pin > of the VCXO > should be when you are locked? > (3) Measure the voltage at the input pin with a scope while the > Controller is ramping to see if it goes past the required voltage. > > Have Fun, > > Brooke Clarke ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Brooks Shera GPS Controller Help
I think I have tried pretty much every suggestion everyone has given me, and probed every pin I was told to. If I had a digital storage scope life would be much easier, but I'm doing the best I can with what I got. Still trying to track down my problem, it seems like the counter at U4 is resetting prematurely. Anyone have a theory as to the cause? Do the two 166 chips @ U5 & U6 have any interaction that could cause this? I'm currently using some ST M74HC166B1 chips (which from Brooks' site said were okay), but I also noticed Mouser has the TI CD74HCT166E chips in stock. I'm willing to order those if someone thinks they might help. Jason ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
