Re: [time-nuts] : L1 GPS timing signal(s) into local time on computer(s)
On Mon, Aug 20, 2012 at 3:10 PM, Sarah White kuze...@gmail.com wrote: I really like that the thunderbolt can (assuming the initial location has been uploaded, or the default site survey has been completed) still keep accurate time / discipline based on a single satellite lock (before falling back on the ovenized crystal in pure holdover mode) All timing mode GPSes can keep time with one GPS sat in view. It works becaus ethe GPS knows it is not moving. and it has the exact location f the one satellite. Holding over when there are zero satellites is not standard and required a good local oscillator. You can built one froma cheap $20 timing GPS and a OCXO and some logic chips. The t-bolt is a GPS with a built-in GPSDO. 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] Fwd: Re: Lucent GPS and RB pair
The software is on ko4bb's site: http://www.ko4bb.com/manuals/index.php?dir=05%29_GPS_Timing/RFTG-m Regards, Pete On Tue, Aug 21, 2012 at 12:35 AM, Randy D. Hunt randy_hunt...@yahoo.comwrote: Original Message Subject:Re: [time-nuts] Lucent GPS and RB pair Date: Mon, 20 Aug 2012 10:00:29 -0700 From: Randy D. Hunt randy_hunt...@yahoo.com To: Discussion of precise time and frequency measurement time-nuts@febo.com On 8/20/2012 9:09 AM, paul swed wrote: Asking the wrong guy. No clue Regards Paul On Sun, Aug 19, 2012 at 11:09 PM, Tom Knox act...@hotmail.com wrote: Hi Paul; Has anyone played with these Lucent units much to see if LH could be tweaked to work? Thanks; Thomas Knox Date: Sun, 19 Aug 2012 22:44:38 -0400 From: paulsw...@gmail.com To: time-nuts@febo.com Subject: Re: [time-nuts] Lucent GPS and RB pair Boy do I agree with Bobs comment. But I have several of the lucent RBs and at least most of mine are quite old. Hey $20 you can't really argue. Or as they say you get what you pay for. So reasonable is a curious question. Or a caution. By the way I am not at all complaining actually. Regards Paul. WB8TSL On Sun, Aug 19, 2012 at 9:13 PM, Bob Camp li...@rtty.us wrote: Hi Compared to the other two, there is a lot less support for the RFTG parts. Lady Heather is a *very* good reason to use a TBolt. Bob On Aug 19, 2012, at 9:06 PM, Jerry jster...@att.net wrote: Hi, I am looking for opinions on the RFT Gm II- XO and RFT Gm II- RB combination compared to TBolt or HP 3815A. I can get the Lucent pair at a very reasonable price. Are manuals easily obtained for them? Thanks Jerry K1JOS __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/**mailman/listinfo/time-nutshttps://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-nutshttps://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-nutshttps://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-nutshttps://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-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. list: I don't know about LH. But the Lucent software is out there. It just takes some searching to find it. I have it around here somewhere. I moved in Feb and still have not got the bench set up. There is some documentation out there too. Just takes some hunting to find it. Check to archives of this list for a lot of it. I have a pair that that had been running 24x7 for about 9 months. no problems. Hope this helps. Randy, KI6WAS __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] Z3815A Internal SMA 10Mhz Output
Every GPSDO has only one 10MHz signal: the one coming from the OCXO. If there are many outputs they must always be the same. When the GPS has the 3D fix (or the position hold) and the algorithm has synchronized the OCXO, the 10MHz can be said locked but, when speaking about GPSDO, the correct word should be disciplined. Yes, maybe there are NCOs and/or synthesizers to put out different synchronized frequencies and signals based on the OCXO 10MHz. On Tue, Aug 21, 2012 at 1:14 AM, Jerry jster...@att.net wrote: In ZL1BPU's GPSR-A User Manual, it mentions that there are internal points that provide access to regenerated system 1pps, 10MHz and 19.6608MHz square wave signals which are present even before the system is locked. After GPZ lock is the internal 10Mhz SMA connector output identical to 10MHz sine wave reference available from the rear coaxial connector block? Jerry K1JOS ___ 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] Z3815A Internal SMA 10Mhz Output
Not every GPSDO has a 10MHz OCXO. 5MHz is, or was, quite common, and I've come across at least one GPSDO with a 10MHz output that I assumed would use a 10MHz OCXO but that also turned out to be based on a 5MHz unit. Then there's the variant of the Trak Microwave 8821B, as just one example, that uses a 16.384MHz OCXO from which they derive a 2.048MHz output without 10MHz anywhere in sight. When I bought one of those a few years ago I assumed that all 8821Bs would be 10MHz GPSDOs, or some nice round figure anyway, and it never even occured to me to ask whether it might be otherwise, which in this particular instance turned out to be a rather expensive mistake:-) regards Nigel GM8PZR In a message dated 21/08/2012 09:39:09 GMT Daylight Time, azelio.bori...@screen.it writes: Every GPSDO has only one 10MHz signal: the one coming from the OCXO. If there are many outputs they must always be the same. When the GPS has the 3D fix (or the position hold) and the algorithm has synchronized the OCXO, the 10MHz can be said locked but, when speaking about GPSDO, the correct word should be disciplined. Yes, maybe there are NCOs and/or synthesizers to put out different synchronized frequencies and signals based on the OCXO 10MHz. On Tue, Aug 21, 2012 at 1:14 AM, Jerry jster...@att.net wrote: In ZL1BPU's GPSR-A User Manual, it mentions that there are internal points that provide access to regenerated system 1pps, 10MHz and 19.6608MHz square wave signals which are present even before the system is locked. After GPZ lock is the internal 10Mhz SMA connector output identical to 10MHz sine wave reference available from the rear coaxial connector block? Jerry K1JOS ___ 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] Thunderbolt distribution amplifier needed.
21/08/2012 11:40 Can anyone please link specifically to a suitable distribution amp for my TB please, either here if it's allowed, or by e-mail to me at ch...@chriswilson.tv ? Cost is a factor, and I am in the UK. An Ebay purchase would be painless. I feel it would be really easy for someone as daft as me to buy something totally unsuitable. I want to run David Partridge's divider board and have enough 10MHz signalleft to run other stuff as well, David recommended I run the amp between the TB and his divider. Cheers. -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv ___ 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] Z3815A Internal SMA 10Mhz Output
Not every GPSDO has a 10MHz OCXO. That is certainly true although from a time-nuts point of view, 10Mhz is certainly a very nice number. I have linked to a photo of both sides of a Trimble 1.5x5 GPSDO built about 2008 that has a 1 square Trimble branded OXCO that has a 76.80Mhz as well as a 1PPS output. It requires 3.3VDC for power. http://i906.photobucket.com/albums/ac262/rjb1998/Trimble76_80.jpg -Arthur ___ 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] Z3815A Internal SMA 10Mhz Output
10MHz would have certainly been more useful to me as a reference source for test gear, my original intention, than the 2.048MHz I ended up with. Nice easy divide down to 1or 2 KHz though, if only I could find a use for that:-) Those photos are of a Trimble Mini-T, I didn't realise they did those with anything other than 10MHz oscillators either! regards Nigel GM8PZR In a message dated 21/08/2012 14:01:00 GMT Daylight Time, golgarfrinc...@yahoo.com writes: That is certainly true although from a time-nuts point of view, 10Mhz is certainly a very nice number. I have linked to a photo of both sides of a Trimble 1.5x5 GPSDO built about 2008 that has a 1 square Trimble branded OXCO that has a 76.80Mhz as well as a 1PPS output. It requires 3.3VDC for power. http://i906.photobucket.com/albums/ac262/rjb1998/Trimble76_80.jpg ___ 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] Z3815A Internal SMA 10Mhz Output
Nigel, you can easily divide the 16.384MHz by 16.384 (2^14) to get 1 kHz for phase locking a 10 MHz oscillator with your GPS box. Adrian gandal...@aol.com schrieb: Not every GPSDO has a 10MHz OCXO. 5MHz is, or was, quite common, and I've come across at least one GPSDO with a 10MHz output that I assumed would use a 10MHz OCXO but that also turned out to be based on a 5MHz unit. Then there's the variant of the Trak Microwave 8821B, as just one example, that uses a 16.384MHz OCXO from which they derive a 2.048MHz output without 10MHz anywhere in sight. When I bought one of those a few years ago I assumed that all 8821Bs would be 10MHz GPSDOs, or some nice round figure anyway, and it never even occured to me to ask whether it might be otherwise, which in this particular instance turned out to be a rather expensive mistake:-) regards Nigel GM8PZR In a message dated 21/08/2012 09:39:09 GMT Daylight Time, azelio.bori...@screen.it writes: Every GPSDO has only one 10MHz signal: the one coming from the OCXO. If there are many outputs they must always be the same. When the GPS has the 3D fix (or the position hold) and the algorithm has synchronized the OCXO, the 10MHz can be said locked but, when speaking about GPSDO, the correct word should be disciplined. Yes, maybe there are NCOs and/or synthesizers to put out different synchronized frequencies and signals based on the OCXO 10MHz. On Tue, Aug 21, 2012 at 1:14 AM, Jerry jster...@att.net wrote: In ZL1BPU's GPSR-A User Manual, it mentions that there are internal points that provide access to regenerated system 1pps, 10MHz and 19.6608MHz square wave signals which are present even before the system is locked. After GPZ lock is the internal 10Mhz SMA connector output identical to 10MHz sine wave reference available from the rear coaxial connector block? Jerry K1JOS ___ 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] Thunderbolt distribution amplifier needed.
From: Chris Wilson ch...@chriswilson.tv
21/08/2012 11:40
Can anyone please link specifically to a suitable distribution amp for
my TB please, either here if it's allowed, or by e-mail to me at
ch...@chriswilson.tv ? Cost is a factor, and I am in the UK. An Ebay
purchase would be painless. I feel it would be really easy for someone
as daft as me to buy something totally unsuitable. I want to run David
Partridge's divider board and have enough 10MHz signalleft to run
other stuff as well, David recommended I run the amp between the TB
and his divider. Cheers.
Chris,
I've been using an Extron ADA 3-80 RGB video DA for distributing standard
frequencies to other instruments. It has worked very well for me. They are
frequently available on Ebay quite cheaply.
.There's a good discussion on using the Extron DA for 10MHz frequency
distribution at http://www.ko4bb.com/ham_radio/Extron_3_80/. There's a
couple on Ebay right now (Item 160867891412 and Item 370641502891 {different
model}). They're in the USA, so shipping to the UK might be a bit painful
unless you can get someone to act as a shipping agent.
Other Extron models will probably do as well... chech out the Extron
literature for details. I like the ADA 3-80 because of the number of inputs
and outputs it offers. Bandwidth is great and noise is low. If you need
really low noise distribution, you will have to determine suitability for
your needs.
Cheers,
Dave M
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[time-nuts] Thunderbolt distribution amplifier needed
Use an analog video distribution amplifier (Grass Valley Group, Leitch, Ross Video etc). These have between 6 to 8 outputs and will provide a reference to various test equipment. From: time-nuts-requ...@febo.com time-nuts-requ...@febo.com To: time-nuts@febo.com Sent: Tuesday, August 21, 2012 6:00 AM Subject: time-nuts Digest, Vol 97, Issue 60 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Thunderbolt distribution amplifier needed. (Chris Wilson) -- Message: 1 Date: Tue, 21 Aug 2012 11:44:17 +0100 From: Chris Wilson ch...@chriswilson.tv To: time-nuts@febo.com time-nuts@febo.com Subject: [time-nuts] Thunderbolt distribution amplifier needed. Message-ID: 5746920.20120821114...@chriswilson.tv Content-Type: text/plain; charset=windows-1252 21/08/2012 11:40 Can anyone please link specifically to a suitable distribution amp for my TB please, either here if it's allowed, or by e-mail to me at ch...@chriswilson.tv ? Cost is a factor, and I am in the UK. An Ebay purchase would be painless. I feel it would be really easy for someone as daft as me to buy something totally unsuitable. I want to run David Partridge's divider board and have enough 10MHz signalleft to run other stuff as well, David recommended I run the amp between the TB and his divider. Cheers. -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv -- ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts End of time-nuts Digest, Vol 97, Issue 60 * ___ 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] Z3815A Internal SMA 10Mhz Output
Not necessary in the Z3815A: it has already a 10MHz output. There are 3 SMB connectors near the rear connector, they are labelled so it should be easy for you to locate the 10MHz and the PPS output. Now I can't open my Z3815A to help, it is in use but from the picture found in Internet I see that the SMB have labels. http://www.vk3hz.net/riglock/VK3II_FT-736_Rig_Locking.pdf It seems (the picture is a little blurry) that the 10MHz output is the central SMB and the 1PPS is the one near the card edge. Then there is a SMB near the Furuno GPS unit but I can't decode from the picture what it is for. On Tue, Aug 21, 2012 at 4:11 PM, Adrian rfn...@arcor.de wrote: Nigel, you can easily divide the 16.384MHz by 16.384 (2^14) to get 1 kHz for phase locking a 10 MHz oscillator with your GPS box. Adrian gandal...@aol.com schrieb: Not every GPSDO has a 10MHz OCXO. 5MHz is, or was, quite common, and I've come across at least one GPSDO with a 10MHz output that I assumed would use a 10MHz OCXO but that also turned out to be based on a 5MHz unit. Then there's the variant of the Trak Microwave 8821B, as just one example, that uses a 16.384MHz OCXO from which they derive a 2.048MHz output without 10MHz anywhere in sight. When I bought one of those a few years ago I assumed that all 8821Bs would be 10MHz GPSDOs, or some nice round figure anyway, and it never even occured to me to ask whether it might be otherwise, which in this particular instance turned out to be a rather expensive mistake:-) regards Nigel GM8PZR In a message dated 21/08/2012 09:39:09 GMT Daylight Time, azelio.bori...@screen.it writes: Every GPSDO has only one 10MHz signal: the one coming from the OCXO. If there are many outputs they must always be the same. When the GPS has the 3D fix (or the position hold) and the algorithm has synchronized the OCXO, the 10MHz can be said locked but, when speaking about GPSDO, the correct word should be disciplined. Yes, maybe there are NCOs and/or synthesizers to put out different synchronized frequencies and signals based on the OCXO 10MHz. On Tue, Aug 21, 2012 at 1:14 AM, Jerry jster...@att.net wrote: In ZL1BPU's GPSR-A User Manual, it mentions that there are internal points that provide access to regenerated system 1pps, 10MHz and 19.6608MHz square wave signals which are present even before the system is locked. After GPZ lock is the internal 10Mhz SMA connector output identical to 10MHz sine wave reference available from the rear coaxial connector block? Jerry K1JOS ___ 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] Z3815A Internal SMA 10Mhz Output
Hi Adrian Yes, I decided that too and may well try it sometime, although it's quite well down the to do pile right now, and it's even made slightly easier as it's already divided down internally to 2.048MHz:-) Ironically, when I bought the Trak unit I already had a 2.048MHz master oscillator system using two ovened crystal oscillators in an auto switchover arrangement, plus the distribution amplifier to match, and I've never found very much use for those either:-) Regards Nigel GM8PZR In a message dated 21/08/2012 15:12:07 GMT Daylight Time, rfn...@arcor.de writes: Nigel, you can easily divide the 16.384MHz by 16.384 (2^14) to get 1 kHz for phase locking a 10 MHz oscillator with your GPS box. Adrian gandal...@aol.com schrieb: Not every GPSDO has a 10MHz OCXO. 5MHz is, or was, quite common, and I've come across at least one GPSDO with a 10MHz output that I assumed would use a 10MHz OCXO but that also turned out to be based on a 5MHz unit. Then there's the variant of the Trak Microwave 8821B, as just one example, that uses a 16.384MHz OCXO from which they derive a 2.048MHz output without 10MHz anywhere in sight. When I bought one of those a few years ago I assumed that all 8821Bs would be 10MHz GPSDOs, or some nice round figure anyway, and it never even occured to me to ask whether it might be otherwise, which in this particular instance turned out to be a rather expensive mistake:-) regards Nigel GM8PZR In a message dated 21/08/2012 09:39:09 GMT Daylight Time, azelio.bori...@screen.it writes: Every GPSDO has only one 10MHz signal: the one coming from the OCXO. If there are many outputs they must always be the same. When the GPS has the 3D fix (or the position hold) and the algorithm has synchronized the OCXO, the 10MHz can be said locked but, when speaking about GPSDO, the correct word should be disciplined. Yes, maybe there are NCOs and/or synthesizers to put out different synchronized frequencies and signals based on the OCXO 10MHz. On Tue, Aug 21, 2012 at 1:14 AM, Jerry jster...@att.net wrote: In ZL1BPU's GPSR-A User Manual, it mentions that there are internal points that provide access to regenerated system 1pps, 10MHz and 19.6608MHz square wave signals which are present even before the system is locked. After GPZ lock is the internal 10Mhz SMA connector output identical to 10MHz sine wave reference available from the rear coaxial connector block? Jerry K1JOS ___ 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] : L1 GPS timing signal(s) into local time on computer(s)
Thanks Chris. I always appreciate clear explanations. I'm assuming that the fixed location requirement is important to note for purposes of compensating for any dopler shift, as well as the distance the signal must first travel before being decoded. ... I would presume that the fixed location used for above calculations would be relative to the position of the antenna? I read somewhere that even compensating for the length of the antenna cabling is important? This is all so exciting. Thanks everyone. On 8/21/2012 2:01 AM, Chris Albertson wrote: On Mon, Aug 20, 2012 at 3:10 PM, Sarah White kuze...@gmail.com wrote: I really like that the thunderbolt can (assuming the initial location has been uploaded, or the default site survey has been completed) still keep accurate time / discipline based on a single satellite lock (before falling back on the ovenized crystal in pure holdover mode) All timing mode GPSes can keep time with one GPS sat in view. It works becaus ethe GPS knows it is not moving. and it has the exact location f the one satellite. Holding over when there are zero satellites is not standard and required a good local oscillator. You can built one froma cheap $20 timing GPS and a OCXO and some logic chips. The t-bolt is a GPS with a built-in GPSDO. 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] : L1 GPS timing signal(s) into local time on computer(s)
On 08/21/2012 12:35 PM, Sarah White wrote: Thanks Chris. I always appreciate clear explanations. I'm assuming that the fixed location requirement is important to note for purposes of compensating for any dopler shift, as well as the distance the signal must first travel before being decoded. ... I would presume that the fixed location used for above calculations would be relative to the position of the antenna? I read somewhere that even compensating for the length of the antenna cabling is important? Yes, the antenna location is what's being measured. You will want to compensate for cable delay but this is simply a matter of subtracting however many nanoseconds it takes the signal to flow through the cable. It does not directly affect the process of doing fixes (whether for position or for time) because the pulses from all of the satellites flow in parallel once they're inside the cable. ___ 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] Modern motherboard with RS232 port
I like to think of it this way: If you are talking instantaneous measurements, then watts is indeed always volts * amps. With a resistive load, the signs of volts and amps are always the same, and the product of the two is always non-negative. If you calculate the average of instantaneous watts over time, you get average power. If you have an inductive load, watts is still volts * amps. But the phase shift between current and voltage means that the instantaneous power is sometimes negative, which means that the load is (at that instant) returning power to the source. But averaging instantaneous watts, both positive and negative values, still gives you average power. The problem comes when we want to calculate watts with devices that only measure voltage, or only measure current. With a resistive load, where the instantaneous power is never negative, you can calculate power by measuring only voltage, calculating the RMS voltage, and knowing the resistance. But that doesn't work for non-resistive loads because the instantaneous current is no longer proportional to the instantaneous voltage. If both are still sinusoidal, knowing the phase shift lets you calculate power. But that doesn't work either for arbitrary waveforms. Dave On Sun, Aug 19, 2012 at 10:32 PM, Chuck Harris cfhar...@erols.com wrote: The long and the short of it is that when AC encounters a reactive load, it results in a current that is not in phase with the voltage. Power is equal to volts x amps only when the current and voltage are in phase which can only happen if the load is purely resistive. If you hang a perfect capacitor across the power line, or a perfect inductor, you will draw lots of current, but no power. -Chuck Harris Tom Knox wrote: Hi Ed; I may not have had enough coffee yet, but if Volt X Amps = Watts why would there be a difference? Best Wishes; Thomas Knox __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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] : L1 GPS timing signal(s) into local time on computer(s)
On Tue, Aug 21, 2012 at 9:35 AM, Sarah White kuze...@gmail.com wrote: Thanks Chris. I always appreciate clear explanations. I'm assuming that the fixed location requirement is important to note for purposes of compensating for any dopler shift, as well as the distance the signal must first travel before being decoded. ... I would presume that the fixed location used for above calculations would be relative to the position of the antenna? I read somewhere that even compensating for the length of the antenna cabling is important? Yes, the GPS' site survey measure the antenna location. And it will not be exactly right unless you measure the cable length. Yes. the cable length delay is close to the speed of light or aboutone nanosecond per foot. Actually there is a correction called velocity factor that a given cable will have. All this is in the Trimble user manual and I'm sure the UMs for other GPSes. There is delay in the serial cable and in any glue logic chps and in the PPS distibution amp.To push the state of the art you have to carefully model all of this. For normal use you may not have to except if you have really long cables. 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] Understanding Oliver Collins Paper Design of Low Jitter Hard Limiters
Hello everyone, I am new to this forum. It looks like a lively discussion on various topics. A colleague of mine here at Agilent pointed me to this paper entitled The Design of Low Jitter Hard Limiters by Oliver Collins. In Bruce Griffiths' precision time in frequency webpage, this paper is described as seminal. (http://www.ko4bb.com/~bruce/ZeroCrossingDetectors.html) Since I'm trying to create a limiter that will accept frequencies ranging from 1 MHz to 100 MHz, I thought it would be good to understand the conclusions of this paper (if not the mathematics as well). The mathematics turned out to be quite challenging to decode. Has someone on this forum unraveled the equations? It appears Collins has recommendations on the bandwidth and gain of a jitter minimizing limiter, and then extends this analysis to provide the bandwidth and gain of a cascade of limiters. But the application is still fuzzy. In figure 5, he shows a graph showing the dependence of jitter on crossing time. Is the crossing time (implied by equations 7) considered a design parameter one can vary? Also, on figure 4, the k parameter has been varied to show the rising waveform as a function of k. The threshold is always assumed to be 0.5. So could k be related to tau, the time constant of the RC filter? Thanks in advance for all your help. Yours Raj ___ 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] Thunderbolt Distribution Amplifier Needed
Chris, I was able to mount my David Partridge divider board inside an Extron ADA 6 300MX television distribution amplifier along with a 1 MHz sine wave filter and a 10 MHz to 100 MHz multiplier. On the front panel is a selector switch for selecting the division ratio, BNC jacks for this and the other board outputs, plus 1 MHz, 10 MHz, and 100 MHz sine wave output connectors. These distribution amplifiers have a very nice case with a blank front panel and are mostly empty inside. Everything inside is powered from the internal Extron power supply, although I had to add a 12/5-V switching convertor and Murata filter to obtain the 320 ma 5-V current needed for the divider board. The internal power supply generates 12 VDC at about 25 VA. a 7508 5V regulator provides +5 VDC to the DA board. An LT1054CT switching convertor develops -12 V that is passed through a 7905 regulator to provide -5 V to the DA. The power supply has vacant 12 V connection points that can be used for powering other devices. This Extron product is intended to provide six 75-ohm outputs each of RGB and sync. I used the sync DA for 1 MHz square wave and the RGB DAs for 1, 10, and 100 MHz sine wave outputs. As I recall, the internal DAs frequency response extends to about 300 MHz. I converted the 75-ohm outputs to 50-ohms by changing the buildout resistors from 75 to 50 ohms. These distribution amplifiers are available rather inexpensively on eBay as a result of the demise of NTSC. I think I paid about US$20. Bruce, KG6OJI ___ 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] : L1 GPS timing signal(s) into local time on computer(s)
Wow. Okay. The user manual actual considers this cable delay to be worth mention? I can see why the trimble thunderbolt is a favorite among time nuts 3 I'm sold. On 8/21/2012 12:48 PM, Chris Albertson wrote: On Tue, Aug 21, 2012 at 9:35 AM, Sarah White kuze...@gmail.com wrote: Thanks Chris. I always appreciate clear explanations. I'm assuming that the fixed location requirement is important to note for purposes of compensating for any dopler shift, as well as the distance the signal must first travel before being decoded. ... I would presume that the fixed location used for above calculations would be relative to the position of the antenna? I read somewhere that even compensating for the length of the antenna cabling is important? Yes, the GPS' site survey measure the antenna location. And it will not be exactly right unless you measure the cable length. Yes. the cable length delay is close to the speed of light or aboutone nanosecond per foot. Actually there is a correction called velocity factor that a given cable will have. All this is in the Trimble user manual and I'm sure the UMs for other GPSes. There is delay in the serial cable and in any glue logic chps and in the PPS distibution amp.To push the state of the art you have to carefully model all of this. For normal use you may not have to except if you have really long cables. 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] Thunderbolt distribution amplifier needed
I bought a eBay video distribution amp. The bandwidth was not as good as I liked but for some reason the opamps were run off +/- 12 volts. Raising the power to +/- 18V greatly improved the performance of the amp. Many video amp assume the signal to 6MHz bandwidth might not be ideal. But on the other hand some old studio equipment is grossly over engineered and might be very good for 10Mhz distribution. The good news is the today analog video amps are cheap as dirt as no one wants analog video. On Tue, Aug 21, 2012 at 7:17 AM, BD Systems Inc. bdsy...@yahoo.com wrote: Use an analog video distribution amplifier (Grass Valley Group, Leitch, Ross Video etc). These have between 6 to 8 outputs and will provide a reference to various test equipment. From: time-nuts-requ...@febo.com time-nuts-requ...@febo.com To: time-nuts@febo.com Sent: Tuesday, August 21, 2012 6:00 AM Subject: time-nuts Digest, Vol 97, Issue 60 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Thunderbolt distribution amplifier needed. (Chris Wilson) -- Message: 1 Date: Tue, 21 Aug 2012 11:44:17 +0100 From: Chris Wilson ch...@chriswilson.tv To: time-nuts@febo.com time-nuts@febo.com Subject: [time-nuts] Thunderbolt distribution amplifier needed. Message-ID: 5746920.20120821114...@chriswilson.tv Content-Type: text/plain; charset=windows-1252 21/08/2012 11:40 Can anyone please link specifically to a suitable distribution amp for my TB please, either here if it's allowed, or by e-mail to me at ch...@chriswilson.tv ? Cost is a factor, and I am in the UK. An Ebay purchase would be painless. I feel it would be really easy for someone as daft as me to buy something totally unsuitable. I want to run David Partridge's divider board and have enough 10MHz signalleft to run other stuff as well, David recommended I run the amp between the TB and his divider. Cheers. -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv -- ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts End of time-nuts Digest, Vol 97, Issue 60 * ___ 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] Thunderbolt distribution amplifier needed
It all depends on the brand and if 'commercial' or not. A Grass Valley (dont remember the model) tested is 3db down starting around 25 MHz. I have also seen others that have a LP filter option installed on the input module. -pete On Tue, Aug 21, 2012 at 9:54 AM, Chris Albertson albertson.ch...@gmail.com wrote: I bought a eBay video distribution amp. The bandwidth was not as good as I liked but for some reason the opamps were run off +/- 12 volts. Raising the power to +/- 18V greatly improved the performance of the amp. Many video amp assume the signal to 6MHz bandwidth might not be ideal. But on the other hand some old studio equipment is grossly over engineered and might be very good for 10Mhz distribution. The good news is the today analog video amps are cheap as dirt as no one wants analog video. On Tue, Aug 21, 2012 at 7:17 AM, BD Systems Inc. bdsy...@yahoo.com wrote: Use an analog video distribution amplifier (Grass Valley Group, Leitch, Ross Video etc). These have between 6 to 8 outputs and will provide a reference to various test equipment. From: time-nuts-requ...@febo.com time-nuts-requ...@febo.com To: time-nuts@febo.com Sent: Tuesday, August 21, 2012 6:00 AM Subject: time-nuts Digest, Vol 97, Issue 60 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Thunderbolt distribution amplifier needed. (Chris Wilson) -- Message: 1 Date: Tue, 21 Aug 2012 11:44:17 +0100 From: Chris Wilson ch...@chriswilson.tv To: time-nuts@febo.com time-nuts@febo.com Subject: [time-nuts] Thunderbolt distribution amplifier needed. Message-ID: 5746920.20120821114...@chriswilson.tv Content-Type: text/plain; charset=windows-1252 21/08/2012 11:40 Can anyone please link specifically to a suitable distribution amp for my TB please, either here if it's allowed, or by e-mail to me at ch...@chriswilson.tv ? Cost is a factor, and I am in the UK. An Ebay purchase would be painless. I feel it would be really easy for someone as daft as me to buy something totally unsuitable. I want to run David Partridge's divider board and have enough 10MHz signalleft to run other stuff as well, David recommended I run the amp between the TB and his divider. Cheers. -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv -- ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts End of time-nuts Digest, Vol 97, Issue 60 * ___ 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. ___ 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] Thunderbolt distribution amplifier needed
Exactly right on many of the accounts. The oldest DAs may be 6 Mhz but I am not sure you will even find them any longer. The more modern preHDTVs were all easily in the 10-30 Mhz region. Most have eq adjustments so that you could peak for the higher frequency like 10 Mhz. Boy the amps and chassis are cheap these days. Stay clear of more complicated DAs like delay if possible. Just lots of stuff to add noise and lots of little jumpers to change. Picked up 2 trays of GVG 8500 class DAs for $30 each. They are junk actually these days. So most are headed to the dumpsters. Regards Paul On Tue, Aug 21, 2012 at 12:54 PM, Chris Albertson albertson.ch...@gmail.com wrote: I bought a eBay video distribution amp. The bandwidth was not as good as I liked but for some reason the opamps were run off +/- 12 volts. Raising the power to +/- 18V greatly improved the performance of the amp. Many video amp assume the signal to 6MHz bandwidth might not be ideal. But on the other hand some old studio equipment is grossly over engineered and might be very good for 10Mhz distribution. The good news is the today analog video amps are cheap as dirt as no one wants analog video. On Tue, Aug 21, 2012 at 7:17 AM, BD Systems Inc. bdsy...@yahoo.com wrote: Use an analog video distribution amplifier (Grass Valley Group, Leitch, Ross Video etc). These have between 6 to 8 outputs and will provide a reference to various test equipment. From: time-nuts-requ...@febo.com time-nuts-requ...@febo.com To: time-nuts@febo.com Sent: Tuesday, August 21, 2012 6:00 AM Subject: time-nuts Digest, Vol 97, Issue 60 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Thunderbolt distribution amplifier needed. (Chris Wilson) -- Message: 1 Date: Tue, 21 Aug 2012 11:44:17 +0100 From: Chris Wilson ch...@chriswilson.tv To: time-nuts@febo.com time-nuts@febo.com Subject: [time-nuts] Thunderbolt distribution amplifier needed. Message-ID: 5746920.20120821114...@chriswilson.tv Content-Type: text/plain; charset=windows-1252 21/08/2012 11:40 Can anyone please link specifically to a suitable distribution amp for my TB please, either here if it's allowed, or by e-mail to me at ch...@chriswilson.tv ? Cost is a factor, and I am in the UK. An Ebay purchase would be painless. I feel it would be really easy for someone as daft as me to buy something totally unsuitable. I want to run David Partridge's divider board and have enough 10MHz signalleft to run other stuff as well, David recommended I run the amp between the TB and his divider. Cheers. -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv -- ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts End of time-nuts Digest, Vol 97, Issue 60 * ___ 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. ___ 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] : L1 GPS timing signal(s) into local time oncomputer(s)
The importance of cable delay depends on what you are doing with the time. If you are taking data in remote locations with different GPS receivers, then cable delay is necessary to correlate the results in time. See the recent mail on FTL neutrinos. If you are being NTP Stratum 0 to one network (please don't assert NTP Stratum 0 to the Internet with a rig put together from eBay parts), then the cable delay is a miniscule phase shift between you and reality. Bill Hawkins -Original Message- From: Sarah White Sent: Tuesday, August 21, 2012 11:53 AM Wow. Okay. The user manual actual considers this cable delay to be worth mention? I can see why the trimble thunderbolt is a favorite among time nuts 3 I'm sold. ___ 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] Maker Faire Sept 29 30 NY Hall of Science
I'm working on a Time-Nuts based exhibit at the 2012 MakerFaire in NYC (http://makerfaire.com/newyork/2012/). The idea is the history of time distribution with a focus on modern timekeeping (1900 to the present). It is a non-commercial booth, focused on education, and demonstrating micro-processing technology and timekeeping. I plan to bring a couple of atomic clocks, various WWV and WWVB receivers, an oscilloscope and GPS devices that I've connected to microprocessors to display the time and also synchronize clocks from the Self Winding Clock Company of NY. My application has been accepted and I'm now working on the actual exhibit. If there is anyone in the NYC area that would like to collaborate on this project, please contact me via email. Any suggestions for the exhibit are appreciated. Thanks. ___ 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] : L1 GPS timing signal(s) into local time on computer(s)
kuze...@gmail.com said: ... I would presume that the fixed location used for above calculations would be relative to the position of the antenna? A side effect of figuring out where you are is figuring out when you are there. There are 4 unknowns: X, Y, Z, T, so you need 4 equations. You get one equation from each satellite so you need 4 satellites. If you assume you are on the surface of the earth, you can get away with only 3 satellites. Yes, that tells you where the antenna is located. If you know where you are, you only need 1 satellite to get the time. I read somewhere that even compensating for the length of the antenna cabling is important? Wow. Okay. The user manual actual considers this cable delay to be worth mention? Sure. The speed of light in air/vacuum is 1 ft/ns. Coax (and fiber) is slower. Junk coax is roughly half as fast. Good coax (foam) is roughly 2/3rds as fast. So it's easy to get 100 ns but unlikely to get more than a microsecond on an amateur budget. Whether that is important for you depends upon your application and the length of the antenna cable. With a modern not super-expensive scope, it's easy to see 1 ns offsets, so cable lengths could be important on something as simple as comparing the PPS outputs from 2 GPS systems. Don't forget to consider the lengths of other cables in your setup. I remember getting an interesting lesson in this area many years ago. We had a couple of scope probes with long cables. I was using one long one and one normal one and looking at high speed digital signals. The offset was enough to confuse me. -- These are my opinions. I hate spam. ___ 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] Thunderbolt distribution amplifier needed.
On Tue, 21 Aug 2012 11:44:17 +0100, Chris Wilson wrote: Can anyone please link specifically to a suitable distribution amp for my TB please, Cost is a factor, and I am in the UK. An Ebay purchase would be painless. I feel it would be really easy for someone as daft as me to buy something totally unsuitable. I use a 350MHz 6-chan RGBHV Dist. Amp. i got cheap off eB..-UK for £30. I think i was lucky there ... It's a A Procon : 4516-01 , same as Solecis: AVB-DA-RGBHV-0106 , and also the same as this one. http://www.amx.com/products/AVB-DA-RGBHV-0106.asp There is what i would think .. a similar unit eB# 200798058748 , but at the listed price, you might want to go for one of the Extrons from US CFO Denmark ___ 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] Z3815A Internal SMA 10Mhz Output
Hi Nigel, Then there's the variant of the Trak Microwave 8821B, as just one example, that uses a 16.384MHz OCXO from which they derive a 2.048MHz output without 10MHz anywhere in sight. When I bought one of those a few years ago I assumed that all 8821Bs would be 10MHz GPSDOs, or some nice round figure anyway, and it never even occured to me to ask whether it might be otherwise, which in this particular instance turned out to be a rather expensive mistake:-) Have one of those Trak 8821B too. It is a bit interesting since the Motorola Oncore VP inside mine has the Z option (phase measurement). -- Björn ___ 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] Understanding Oliver Collins Paper Design of Low Jitter Hard Limiters
On Tue, 21 Aug 2012 10:50:43 -0600, raj_so...@agilent.com wrote: Hello everyone, I am new to this forum. It looks like a lively discussion on various topics. A colleague of mine here at Agilent pointed me to this paper entitled The Design of Low Jitter Hard Limiters by Oliver Collins. In Bruce Griffiths' precision time in frequency webpage, this paper is described as seminal. (http://www.ko4bb.com/~bruce/ZeroCrossingDetectors.html) Since I'm trying to create a limiter that will accept frequencies ranging from 1 MHz to 100 MHz, I thought it would be good to understand the conclusions of this paper (if not the mathematics as well). The mathematics turned out to be quite challenging to decode. Has someone on this forum unraveled the equations? It appears Collins has recommendations on the bandwidth and gain of a jitter minimizing limiter, and then extends this analysis to provide the bandwidth and gain of a cascade of limiters. But the application is still fuzzy. In figure 5, he shows a graph showing the dependence of jitter on crossing time. Is the crossing time (implied by equations 7) considered a design parameter one can vary? Also, on figure 4, the k parameter has been varied to show the rising waveform as a function of k. The threshold is always assumed to be 0.5. So could k be related to tau, the time constant of the RC filter? Thanks in advance for all your help. Yours Raj I would love to take a look at this but the links to the paper at the IEEE are dead. My Google search just turned up others looking for the same paper. ___ 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] Understanding Oliver Collins Paper Design of Low Jitter Hard Limiters
On 8/21/2012 1:22 PM, David wrote: On Tue, 21 Aug 2012 10:50:43 -0600,raj_so...@agilent.com wrote: Hello everyone, I am new to this forum. It looks like a lively discussion on various topics. A colleague of mine here at Agilent pointed me to this paper entitled The Design of Low Jitter Hard Limiters by Oliver Collins. In Bruce Griffiths' precision time in frequency webpage, this paper is described as seminal. (http://www.ko4bb.com/~bruce/ZeroCrossingDetectors.html) Since I'm trying to create a limiter that will accept frequencies ranging from 1 MHz to 100 MHz, I thought it would be good to understand the conclusions of this paper (if not the mathematics as well). The mathematics turned out to be quite challenging to decode. Has someone on this forum unraveled the equations? It appears Collins has recommendations on the bandwidth and gain of a jitter minimizing limiter, and then extends this analysis to provide the bandwidth and gain of a cascade of limiters. But the application is still fuzzy. In figure 5, he shows a graph showing the dependence of jitter on crossing time. Is the crossing time (implied by equations 7) considered a design parameter one can vary? Also, on figure 4, the k parameter has been varied to show the rising waveform as a function of k. The threshold is always assumed to be 0.5. So could k be related to tau, the time constant of the RC filter? Thanks in advance for all your help. Yours Raj I would love to take a look at this but the links to the paper at the IEEE are dead. My Google search just turned up others looking for the same paper. Just search for the title on IEEE - http://ieeexplore.ieee.org/search/searchresult.jsp?newsearch=truequeryText=The+Design+of+Low+Jitter+Hard+Limitersx=29y=18 Of course then you need to figure out how to pay IEEE for the privilege of reading the 672 kb paper. ___ 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] Understanding Oliver Collins Paper Design of Low Jitter Hard Limiters
Hi Everyone, I uploaded the paper to my music website. http://www.rajsodhi.com/images/The%20Design%20of%20Low%20Jitter%20Hard%20Limiters,%20Oliver%20Collins%20May%201996.pdf Yours, Raj -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Rex Sent: Tuesday, August 21, 2012 1:39 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Understanding Oliver Collins Paper Design of Low Jitter Hard Limiters On 8/21/2012 1:22 PM, David wrote: On Tue, 21 Aug 2012 10:50:43 -0600,raj_so...@agilent.com wrote: Hello everyone, I am new to this forum. It looks like a lively discussion on various topics. A colleague of mine here at Agilent pointed me to this paper entitled The Design of Low Jitter Hard Limiters by Oliver Collins. In Bruce Griffiths' precision time in frequency webpage, this paper is described as seminal. (http://www.ko4bb.com/~bruce/ZeroCrossingDetectors.html) Since I'm trying to create a limiter that will accept frequencies ranging from 1 MHz to 100 MHz, I thought it would be good to understand the conclusions of this paper (if not the mathematics as well). The mathematics turned out to be quite challenging to decode. Has someone on this forum unraveled the equations? It appears Collins has recommendations on the bandwidth and gain of a jitter minimizing limiter, and then extends this analysis to provide the bandwidth and gain of a cascade of limiters. But the application is still fuzzy. In figure 5, he shows a graph showing the dependence of jitter on crossing time. Is the crossing time (implied by equations 7) considered a design parameter one can vary? Also, on figure 4, the k parameter has been varied to show the rising waveform as a function of k. The threshold is always assumed to be 0.5. So could k be related to tau, the time constant of the RC filter? Thanks in advance for all your help. Yours Raj I would love to take a look at this but the links to the paper at the IEEE are dead. My Google search just turned up others looking for the same paper. Just search for the title on IEEE - http://ieeexplore.ieee.org/search/searchresult.jsp?newsearch=truequeryText=The+Design+of+Low+Jitter+Hard+Limitersx=29y=18 Of course then you need to figure out how to pay IEEE for the privilege of reading the 672 kb paper. ___ 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] Understanding Oliver Collins Paper Design of Low Jitter Hard Limiters
Hi Raj, On 08/21/2012 06:50 PM, raj_so...@agilent.com wrote: Hello everyone, I am new to this forum. It looks like a lively discussion on various topics. A colleague of mine here at Agilent pointed me to this paper entitled The Design of Low Jitter Hard Limiters by Oliver Collins. In Bruce Griffiths' precision time in frequency webpage, this paper is described as seminal. (http://www.ko4bb.com/~bruce/ZeroCrossingDetectors.html) This is indeed a good paper to read. Since I'm trying to create a limiter that will accept frequencies ranging from 1 MHz to 100 MHz, I thought it would be good to understand the conclusions of this paper (if not the mathematics as well). I agree that it could be very good to understand the paper for such a design. The mathematics turned out to be quite challenging to decode. Has someone on this forum unraveled the equations? Both Bruce and me have been looking deeply into this paper (even if it where some time ago, so I re-read it quickly). Bruce deeper than me, but I think I can guide you into it. It appears Collins has recommendations on the bandwidth and gain of a jitter minimizing limiter, and then extends this analysis to provide the bandwidth and gain of a cascade of limiters. But the application is still fuzzy. You obviously have not paid attention to Chapter 1 where the application is very clear and obvious. In particular Dual Mixer Time Difference (DMTD) systems (of which one side is seen in Figure 1) is being discussed, but I think it is equally valid in your application, as it relates to the overall basic issue Given a sine of a particular frequency, which limiter will provide me with minimum trigger jitter? In figure 5, he shows a graph showing the dependence of jitter on crossing time. Is the crossing time (implied by equations 7) considered a design parameter one can vary? Yes, k is the design parameter as the normalized crossing time. Also, on figure 4, the k parameter has been varied to show the rising waveform as a function of k. It essentially shows you how the filter bandwidth (as tau shifts with k) will affect the output signal as a function of the design parameter k. The threshold is always assumed to be 0.5. So could k be related to tau, the time constant of the RC filter? That is formula 10. Actually, you can pick one of many different parameters as the one for the one degree of freedom parameter, and he has chosen the normalized crossing time k. Just about any other normalized parameter could have worked as well. Bruce observed that the same amount of contributed noise was assumed in the Collins paper, so you would like to read his notes of: http://www.ko4bb.com/~bruce/GeneralisedCollinsHardLimiterPaperV3B.pdf Oh, an interesting note is that the Collins paper considers what happens on a single transition, so that's why it is relatively clean from input frequency issues. What will change is the input slew-rate. The Collins paper does not very clearly advice you how to deal with 1:100 input frequency design-range, even if it occurs as an example of variation, just scalled down a million times from your design problem. Another possible critique on the Collins paper is that it only consider white noise, and not flicker noise. For low frequencies, flicker would be noticeable if not dominant, where as for higher frequencies the white noise assumption works pretty well. 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] Understanding Oliver Collins Paper Design of Low Jitter Hard Limiters
Hi Raj, welcome. Thank you for joining the group and thanks to Magnus for his comment about the Collins' paper. On Tue, Aug 21, 2012 at 11:51 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Hi Raj, On 08/21/2012 06:50 PM, raj_so...@agilent.com wrote: Hello everyone, I am new to this forum. It looks like a lively discussion on various topics. A colleague of mine here at Agilent pointed me to this paper entitled The Design of Low Jitter Hard Limiters by Oliver Collins. In Bruce Griffiths' precision time in frequency webpage, this paper is described as seminal. (http://www.ko4bb.com/~bruce/ZeroCrossingDetectors.html) This is indeed a good paper to read. Since I'm trying to create a limiter that will accept frequencies ranging from 1 MHz to 100 MHz, I thought it would be good to understand the conclusions of this paper (if not the mathematics as well). I agree that it could be very good to understand the paper for such a design. The mathematics turned out to be quite challenging to decode. Has someone on this forum unraveled the equations? Both Bruce and me have been looking deeply into this paper (even if it where some time ago, so I re-read it quickly). Bruce deeper than me, but I think I can guide you into it. It appears Collins has recommendations on the bandwidth and gain of a jitter minimizing limiter, and then extends this analysis to provide the bandwidth and gain of a cascade of limiters. But the application is still fuzzy. You obviously have not paid attention to Chapter 1 where the application is very clear and obvious. In particular Dual Mixer Time Difference (DMTD) systems (of which one side is seen in Figure 1) is being discussed, but I think it is equally valid in your application, as it relates to the overall basic issue Given a sine of a particular frequency, which limiter will provide me with minimum trigger jitter? In figure 5, he shows a graph showing the dependence of jitter on crossing time. Is the crossing time (implied by equations 7) considered a design parameter one can vary? Yes, k is the design parameter as the normalized crossing time. Also, on figure 4, the k parameter has been varied to show the rising waveform as a function of k. It essentially shows you how the filter bandwidth (as tau shifts with k) will affect the output signal as a function of the design parameter k. The threshold is always assumed to be 0.5. So could k be related to tau, the time constant of the RC filter? That is formula 10. Actually, you can pick one of many different parameters as the one for the one degree of freedom parameter, and he has chosen the normalized crossing time k. Just about any other normalized parameter could have worked as well. Bruce observed that the same amount of contributed noise was assumed in the Collins paper, so you would like to read his notes of: http://www.ko4bb.com/~bruce/GeneralisedCollinsHardLimiterPaperV3B.pdf Oh, an interesting note is that the Collins paper considers what happens on a single transition, so that's why it is relatively clean from input frequency issues. What will change is the input slew-rate. The Collins paper does not very clearly advice you how to deal with 1:100 input frequency design-range, even if it occurs as an example of variation, just scalled down a million times from your design problem. Another possible critique on the Collins paper is that it only consider white noise, and not flicker noise. For low frequencies, flicker would be noticeable if not dominant, where as for higher frequencies the white noise assumption works pretty well. 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. ___ 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] Understanding Oliver Collins Paper Design of Low Jitter Hard Limiters
Hi Since the Collins approach tunes the system for a single frequency input (more or less), the approach is probably not the best for a many decades sort of frequency range. There are a number of things that he alludes to in the paper, but does not directly address. The most obvious is the temperature dependance of the stuff the system is made of. Another is the simple fact that a non-clipping linear amplifier is likely the best choice for a first stage, provide the input is not already near clipping. Bob On Aug 21, 2012, at 12:50 PM, raj_so...@agilent.com wrote: Hello everyone, I am new to this forum. It looks like a lively discussion on various topics. A colleague of mine here at Agilent pointed me to this paper entitled The Design of Low Jitter Hard Limiters by Oliver Collins. In Bruce Griffiths' precision time in frequency webpage, this paper is described as seminal. (http://www.ko4bb.com/~bruce/ZeroCrossingDetectors.html) Since I'm trying to create a limiter that will accept frequencies ranging from 1 MHz to 100 MHz, I thought it would be good to understand the conclusions of this paper (if not the mathematics as well). The mathematics turned out to be quite challenging to decode. Has someone on this forum unraveled the equations? It appears Collins has recommendations on the bandwidth and gain of a jitter minimizing limiter, and then extends this analysis to provide the bandwidth and gain of a cascade of limiters. But the application is still fuzzy. In figure 5, he shows a graph showing the dependence of jitter on crossing time. Is the crossing time (implied by equations 7) considered a design parameter one can vary? Also, on figure 4, the k parameter has been varied to show the rising waveform as a function of k. The threshold is always assumed to be 0.5. So could k be related to tau, the time constant of the RC filter? Thanks in advance for all your help. Yours Raj ___ 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] Gray T Bolt
Does any one know about a gray cased Thunderbolt? This unit is backwards from the gold box T-Bolt. The circuit card is mounted on the non-flanged case half (that has the connector cutouts). There is no serial number sticker, but does have the power supply sticker next to the connector. And just for fun, the power connector is backwards from the gold box units. You can guess the next line... Does anyone need a T Bolt Aroma Therapy device? One scent (not pleasant), slightly used, real cheap. I was rearranging the bench and plugged a properly keyed power supply into the gray box. The power supply that I did have on this unit doesn't have the keying lock. Of course, this one has (had) the good DS1620 (D rev) chip. Oh well, live and learn. Mike ___ 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] Thunderbolt distribution amplifier needed
I currently use a Grass Valley Group 8802 video distribution amp (DA). Yes they start to roll-off the frequency at 6 MHz but the roll-off is gradual and it will certianly pass 10 MHz with no problem. Remember you are not passing multple frequencies or multi-burst, just 10 MHz. Also, these DAs are designed be unity gain and to handle approximately 1 volt p-p so be carefull of clipping if you drive much more than that level or alternatively, pad down the input to a 1 volt level. From: time-nuts-requ...@febo.com time-nuts-requ...@febo.com To: time-nuts@febo.com Sent: Tuesday, August 21, 2012 1:00 PM Subject: time-nuts Digest, Vol 97, Issue 63 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Re: Thunderbolt distribution amplifier needed (Chris Albertson) 2. Re: Thunderbolt distribution amplifier needed (Pete Lancashire) 3. Re: Thunderbolt distribution amplifier needed (paul swed) 4. Re: : L1 GPS timing signal(s) into local time oncomputer(s) (Bill Hawkins) 5. Maker Faire Sept 29 30 NY Hall of Science (MITCHELL JANOFF) 6. Re: : L1 GPS timing signal(s) into local time on computer(s) (Hal Murray) -- Message: 1 Date: Tue, 21 Aug 2012 09:54:14 -0700 From: Chris Albertson albertson.ch...@gmail.com To: BD Systems Inc. bdsy...@yahoo.com, Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Thunderbolt distribution amplifier needed Message-ID: cabbxvhtkvh5wixxzoeyo2-nv51ev2vnrsbapaoj851-pyda...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 I bought a eBay video distribution amp. The bandwidth was not as good as I liked but for some reason the opamps were run off +/- 12 volts. Raising the power to +/- 18V greatly improved the performance of the amp. Many video amp assume the signal to 6MHz bandwidth might not be ideal. But on the other hand some old studio equipment is grossly over engineered and might be very good for 10Mhz distribution. The good news is the today analog video amps are cheap as dirt as no one wants analog video. On Tue, Aug 21, 2012 at 7:17 AM, BD Systems Inc. bdsy...@yahoo.com wrote: Use an analog video distribution amplifier (Grass Valley Group, Leitch, Ross Video etc). These have between 6 to 8 outputs and will provide a reference to various test equipment. From: time-nuts-requ...@febo.com time-nuts-requ...@febo.com To: time-nuts@febo.com Sent: Tuesday, August 21, 2012 6:00 AM Subject: time-nuts Digest, Vol 97, Issue 60 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Thunderbolt distribution amplifier needed. (Chris Wilson) -- Message: 1 Date: Tue, 21 Aug 2012 11:44:17 +0100 From: Chris Wilson ch...@chriswilson.tv To: time-nuts@febo.com time-nuts@febo.com Subject: [time-nuts] Thunderbolt distribution amplifier needed. Message-ID: 5746920.20120821114...@chriswilson.tv Content-Type: text/plain; charset=windows-1252 21/08/2012 11:40 Can anyone please link specifically to a suitable distribution amp for my TB please, either here if it's allowed, or by e-mail to me at ch...@chriswilson.tv ? Cost is a factor, and I am in the UK. An Ebay purchase would be painless. I feel it would be really easy for someone as daft as me to buy something totally unsuitable. I want to run David Partridge's divider board and have enough 10MHz signalleft to run other stuff as well, David recommended I run the amp between the TB and his divider. Cheers. -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv -- ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts End of time-nuts Digest, Vol 97, Issue 60 * ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
[time-nuts] HP-5065a bought and finally working!
Dear Group, I wish you well. Do you recall a message and thread about a month ago with my concerns about buying a used / unknown condition HP-5065a rubidium frequency standard? I bit the bullet and bought it. Almost mint condition (cosmetically speaking) and with several operational issues. Well, It took me several weeks to put it back to work. Several capacitors on several boards along with a couple of transistors and an IC were replaced. After that any being bored by the yellow light, it finally came off to allow a beautiful green lock condition light. I went through the necessary steps to tune it and calibrate it. Now, as I have been told recently. You have been bitten by the Time Nuts bug. I am not complaining at all. Now the technical issues if you kindly allow: a. Does anybody have an HP-5065a manual for the latest versions? Mine (which I downloaded from the Internet) is intended for earlier versions. It seems I have one of the last produced units. I would kindly appreciate any help on this and I am willing to pay for time and expenses to anybody who could help. During the repair process I found several differences in the earlier versions design and had to figure out hoy mine works. b. Is it possible to build a GPSDRb? I would like to know if it is reasonable to pursue the goal to discipline the 5065a with a TB which I also got recently. c. I am waiting for the delivery of a recent purchase. An HP-59309a Digital Clock to go with the HP 5065a. How I wish I could find the optional LED integrated optional clock and 1PPS output. Is my purchase a good match for the 5065a? Any other suggestions to drive a clock? d. I am waiting also for de delivery of an HP-105b mint condition quartz frequency standard. Would a second 59309a make sense to use it with this quartz standard? Or just saving it for a Cesium? Anybody willing to sell a spare, dust gathering, clean unit to me? e. Any suggestions for software of lab equipment to measure my experiments like AD, jitter, phase comparisons, etc? While I wait I am doing some experiments with a FE Rb standard to discipline an Adret synthesiser to output 32.768 KHz to directly drive a Nixie clock kit I just finished building. Your comments are surely welcome. Thank you! Kind regards, Edgardo Molina XE1XUS Mexico ___ 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.
