Re: [time-nuts] Ebay FE-5680A Rb: Connections and Features
Well done Bert, at last some sensible information regarding the multiplicity of models of this Rb. I obtained my example from Fluke I for the higher price - but he assures me that it is the RS232 programmable unit. I have not had the opportunity to investigate it fully, but it would seem not to require the additional 5 volt supply. The power requirements are 15 volts, at initially 1.9 Amps, reducing to 680/700mA. Without any programming, it provides a 1pps. signal from pin 6 of the 9-pin D connector. According to my 53131A (locked to the GPS standard), the 1 pps is 1.000,000,001 s. The modifications to the unit made by an earlier owner, suggests bringing the (selected) signal out form the case, to a separate BNC, and another 9 pin D for the RS232. Somebody on the list has suggested that it could do damage to this variant, to connect 5 volts to pin 4, to date I have not done this, Can any member confirm these details. Thanks. Roy -- From: ewkeh...@aol.com Sent: Monday, December 12, 2011 12:25 AM To: time-nuts@febo.com Subject: Re: [time-nuts] Ebay FE-5680A Rb: Connections and Features Sorry I ever started this. In the past the FE5680's started out with a 50.255 MHz XTAL, some time in the 2002 2003 timeframe they switched to 60 MHz using a DDS in the loop. All of these units can only be stepped in 7 E-13 steps limited by the resolution of the DDS. Having followed all the listings on this subject is it safe to assume that 99% of the units sold in the $ 40 range are identical in that respect. At prior times there was and still is a unit available that from the 50.255 drives a DDS and a programmable output is available at a premium price. All seem to be above $ 100. Claims that the 60 MHz units can be set in 1 E-13 is bogus and misleading. Maybe if you dither the input, but since the loop is most likely digital I do not know what that will do. Accept 7 E -13 or do as I will do, use the C field. Pin 8 and 9 are RS 232. Bert Kehren In a message dated 12/11/2011 5:46:05 P.M. Eastern Standard Time, snapp...@gmail.com writes: Like many of you, I have seen these advertised on Ebay at good prices. Also, like many of you, I am confused about the 'programmability' and connections. Many of them advertise these connections:- PIN 1: INPUT +15V to +18V PIN 2: GROUND PIN 3: LOCK/UNLOCK (high = unlock) PIN 4: INPUT +5V PIN 5: GROUND PIN 7: OUTPUT ( 10MHz sinewave ) Many of them also say Digitally programmable to 1x10-13, with the above connections. (Many of the sites seem to have the same descriptive text.) On questioning one of them about how the programming was done, they replied Not with this model; only with the more expensive one he sells ! But from what I read in some of the time-nuts contributions, there is sometimes (?) or often (?) also these connections:- Pin 6 1 pps out Pin 8 RS-232 Rx (into rubidium) Pin 9 RS-232 Tx (from rubidium) Can anyone tell me if they ALL have the MAX level shifter/driver chip fitted, even though it may not be connected to the connector ? I don't want full programmability, just 10 MHz frequency correction. Perhaps I just have to take pot luck when I buy ? What are my chances of getting one with the 'hidden' RS232 and 1PPS output ? All advice 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. ___ 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] Question re neutrinos and GPS
On Sat, Jan 7, 2012 at 11:51 AM, Attila Kinali att...@kinali.ch wrote: On Fri, 6 Jan 2012 15:55:12 -0800 Tom Van Baak t...@leapsecond.com wrote: Hopefully all this GPS-neutrino talk will calm down when other methods to validate the synchronization of the clocks at CERN and LNGS are done (e.g., direct fiber or traveling Cs clocks). According to [1] they already did that. Attila Kinali [1] http://arxiv.org/abs/1109.4897 No, we have not made any serious attempt at cross-checking the GPS time transfer system with something which is *independent* of GPS. We are currently planning for the Spring, along three lines: - Traveling Cs. - Direct fiber connection. - Two Way Satellite Time Transfer (TWSTT). You can see the archives at http://www.ohwr.org/mailing_list/show?project_id=cngs-time-transfer for details. 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] Question re neutrinos and GPS
On Jan 8 2012 14:02 javier.serrano.par...@gmail.com wrote: Tom Van Baak t...@leapsecond.com wrote: Hopefully all this GPS-neutrino talk will calm down when other methods to validate the synchronization of the clocks at CERN and LNGS are done (e.g., direct fiber or traveling Cs clocks). According to [1] they already did that. Attila Kinali [1] http://arxiv.org/abs/1109.4897 No, we have not made any serious attempt at cross-checking the GPS time transfer system with something which is *independent* of GPS. We are currently planning for the Spring, along three lines: - Traveling Cs. - Direct fiber connection. - Two Way Satellite Time Transfer (TWSTT). You can see the archives at http://www.ohwr.org/mailing_list/show?project_id=cngs-time-transfer for details. Cheers, Javier Hi Javier, what about swapping the Cs clocks between CERN and LNGS without re- synchronizing them, and repeating the neutrino test? Antonio I8IOV ___ 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] Question re neutrinos and GPS
On 01/08/2012 02:02 PM, Javier Serrano wrote: On Sat, Jan 7, 2012 at 11:51 AM, Attila Kinaliatt...@kinali.ch wrote: On Fri, 6 Jan 2012 15:55:12 -0800 Tom Van Baakt...@leapsecond.com wrote: Hopefully all this GPS-neutrino talk will calm down when other methods to validate the synchronization of the clocks at CERN and LNGS are done (e.g., direct fiber or traveling Cs clocks). According to [1] they already did that. Attila Kinali [1] http://arxiv.org/abs/1109.4897 No, we have not made any serious attempt at cross-checking the GPS time transfer system with something which is *independent* of GPS. What have been done is PTB used their traveling GPS receiver, a GTR 50 receiver, with a GPS-702 antenna and a bundled SR-620 counter. There is a report from that exercise. 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] Question re neutrinos and GPS
what about swapping the Cs clocks between CERN and LNGS without re- synchronizing them, and repeating the neutrino test? Antonio I8IOV Right, typically when you perform a traveling clock experiment you don't touch the clocks -- you don't need to synchronize or resynchronize anything. The key point is the difference in time from A to B, or A to B to A. This is accomplished with a time interval counter and you do the subtraction with a calculator. Imagine that you have two Rb in your house and wish to compare their times. If they are too far apart to use a long cable, one trick is to use a traveling quartz clock and TIC. You measure Rb1-Qz and then walk to the other clock in order to measure Rb2-Qz. Ignoring effects like drift in quartz or counter, the time of the quartz drops out of the calculation of Rb2-Rb1. Make sense? So there's no mathematical requirement for synchronization of the traveling clock. And there's also a practical reason why you don't precisely synchronize or resynchronize -- most Cs have a 100 ns granularity on their 1PPS sync input. /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] Ebay FE-5680A Rb: Connections and Features
Hi Roy If your unit is generating an output as you report, without 5 volts to pin 4, then I'd leave well alone. On the current batches of cheaper units, that do require a 5 volt supply to pin 4, they won't lock or provide an output without it. Removing that 5 volt supply from a unit that's already up and running, on two that I've tested so far anyway, causes it to lose lock and the 10MHz output collapses, which would seem to be a fairly strong indication that on these units it is needed:-) regards Nigel GM8PZR In a message dated 08/01/2012 12:57:57 GMT Standard Time, phill...@btinternet.com writes: Somebody on the list has suggested that it could do damage to this variant, to connect 5 volts to pin 4, to date I have not done this, Can any member confirm these details. ___ 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] Ebay FE-5680A Rb: Connections and Features
Nigel Thanks for your comments - - the plot thickens. Would this indicate that the 5 volt supply required for general internal use is obtained by an internal Vreg. from the basic 15 volt supply - - I would guess so because the overall current requirement would seem to be similar ? What is for sure, is that the manufacturers offered this product in various bespoke styles without any external (case) indication. We await those of you that are keen and able to investigate in depth. By the way, I gave the Russian Rb unit, which came out of my Quartzlock 10A-R, to a new Time-nut in my locality. I note that another Quartzlock 10A-R is currently being offered by one of our popular websites - I wonder if it has the same Rb unit ? Regards Roy -Original Message- From: gandal...@aol.com Sent: Sunday, January 08, 2012 3:49 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Ebay FE-5680A Rb: Connections and Features Hi Roy If your unit is generating an output as you report, without 5 volts to pin 4, then I'd leave well alone. On the current batches of cheaper units, that do require a 5 volt supply to pin 4, they won't lock or provide an output without it. Removing that 5 volt supply from a unit that's already up and running, on two that I've tested so far anyway, causes it to lose lock and the 10MHz output collapses, which would seem to be a fairly strong indication that on these units it is needed:-) regards Nigel GM8PZR In a message dated 08/01/2012 12:57:57 GMT Standard Time, phill...@btinternet.com writes: Somebody on the list has suggested that it could do damage to this variant, to connect 5 volts to pin 4, to date I have not done this, Can any member confirm these details. ___ 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] HP Z3817A Reverse Engineering
I recently purchased a Motorola STLN4096A with the HP E1938A oscillator. I bought it for the oscillator only. Then I got intrigued by the HP Z3817A GPSDO that's included. I've reverse engineered most of it and I've got it running. The 1 PPS is really good ( 1000 measurements, Std. Dev. of 200 ps, min to max range of 1.5 ns) and the HUP is very slowly dropping (currently at 13 us after ~1.5 days) as the oscillator works out the kinks after it's long sleep. It's dropping much slower than my Z3801A did when I first turned it on. There's one input that I haven't been able to figure out. I've got data in and 1 PPS in from the GPS receiver. Everything seems to be working so I'm at a loss what that the other input could be for. There are no clues to it's function because it appears to go into one of the Xilinx chips. Does anyone have any more info on the unit? Has anyone figured out the other input? I have searched the net and the archives. There's very little info or discussion on this unit. Ed ___ 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] HP Z3817A Reverse Engineering
Have you already this? On the TIB (P1) DB-25 connector, I'm fairly confident about these: V+ pins 1 and 21 V- pins 8 and 25 10MHz #1 pins 2/15 xfmr coupled, ~4.6V into 1M 10MHz #2 pins 23/16 xfmr coupled, ~4.6V into 1M 1PPS pin 14 Supply voltage is dictated by Lucent DC-DC converter. Input is 18-36V, 1.9A. Still chasing down the other pins. Currently I am working on a possible disciplining input: input of some kind to U6/3 via 100 ohms pin 18, prob. diff with 4 input of some kind to U6/2 via 100 ohms pin 4, prob. diff with 18 The MMI (J1) DB-9 connector is RS-232, 9600baud, 8n1 and runs a a familiar SCPI interface. On Sun, Jan 8, 2012 at 6:20 PM, Ed Palmer ed_pal...@sasktel.net wrote: I recently purchased a Motorola STLN4096A with the HP E1938A oscillator. I bought it for the oscillator only. Then I got intrigued by the HP Z3817A GPSDO that's included. I've reverse engineered most of it and I've got it running. The 1 PPS is really good ( 1000 measurements, Std. Dev. of 200 ps, min to max range of 1.5 ns) and the HUP is very slowly dropping (currently at 13 us after ~1.5 days) as the oscillator works out the kinks after it's long sleep. It's dropping much slower than my Z3801A did when I first turned it on. There's one input that I haven't been able to figure out. I've got data in and 1 PPS in from the GPS receiver. Everything seems to be working so I'm at a loss what that the other input could be for. There are no clues to it's function because it appears to go into one of the Xilinx chips. Does anyone have any more info on the unit? Has anyone figured out the other input? I have searched the net and the archives. There's very little info or discussion on this unit. Ed ___ 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] Question re neutrinos and GPS
Tom, I had to look up traveling clock synchronization to get a better understanding, and found this link: http://www.newtonphysics.on.ca/einstein/chapter9.html The idea that Qz (time on the quartz clock, no?) drops out in the subtraction seems to me to require Qz to be invariant. That seems beyond the capability of quartz at the required error of one microsecond during the many hours that it will take to transport Q between CERN and LNGS. Plenty of time for cracks to propagate or chips fall off. Why do you say we can ignore such effects? Thanks for any enlightenment. Bill Hawkins -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Van Baak Sent: Sunday, January 08, 2012 9:11 AM To: iov...@inwind.it Cc: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Question re neutrinos and GPS what about swapping the Cs clocks between CERN and LNGS without re- synchronizing them, and repeating the neutrino test? Antonio I8IOV Right, typically when you perform a traveling clock experiment you don't touch the clocks -- you don't need to synchronize or resynchronize anything. The key point is the difference in time from A to B, or A to B to A. This is accomplished with a time interval counter and you do the subtraction with a calculator. Imagine that you have two Rb in your house and wish to compare their times. If they are too far apart to use a long cable, one trick is to use a traveling quartz clock and TIC. You measure Rb1-Qz and then walk to the other clock in order to measure Rb2-Qz. Ignoring effects like drift in quartz or counter, the time of the quartz drops out of the calculation of Rb2-Rb1. Make sense? So there's no mathematical requirement for synchronization of the traveling clock. And there's also a practical reason why you don't precisely synchronize or resynchronize -- most Cs have a 100 ns granularity on their 1PPS sync input. /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. ___ 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] HP Z3817A Reverse Engineering
Hi Azelio, Thanks, but I already found that. I've moved quite a bit beyond that. That message was one of the few in the archives that had any significant info on this unit. For some reason, I find that surprising. Ed On 1/8/2012 11:33 AM, Azelio Boriani wrote: Have you already this? On the TIB (P1) DB-25 connector, I'm fairly confident about these: V+ pins 1 and 21 V- pins 8 and 25 10MHz #1 pins 2/15 xfmr coupled, ~4.6V into 1M 10MHz #2 pins 23/16 xfmr coupled, ~4.6V into 1M 1PPS pin 14 Supply voltage is dictated by Lucent DC-DC converter. Input is 18-36V, 1.9A. Still chasing down the other pins. Currently I am working on a possible disciplining input: input of some kind to U6/3 via 100 ohms pin 18, prob. diff with 4 input of some kind to U6/2 via 100 ohms pin 4, prob. diff with 18 The MMI (J1) DB-9 connector is RS-232, 9600baud, 8n1 and runs a a familiar SCPI interface. On Sun, Jan 8, 2012 at 6:20 PM, Ed Palmered_pal...@sasktel.net wrote: I recently purchased a Motorola STLN4096A with the HP E1938A oscillator. I bought it for the oscillator only. Then I got intrigued by the HP Z3817A GPSDO that's included. I've reverse engineered most of it and I've got it running. The 1 PPS is really good ( 1000 measurements, Std. Dev. of200 ps, min to max range of1.5 ns) and the HUP is very slowly dropping (currently at 13 us after ~1.5 days) as the oscillator works out the kinks after it's long sleep. It's dropping much slower than my Z3801A did when I first turned it on. There's one input that I haven't been able to figure out. I've got data in and 1 PPS in from the GPS receiver. Everything seems to be working so I'm at a loss what that the other input could be for. There are no clues to it's function because it appears to go into one of the Xilinx chips. Does anyone have any more info on the unit? Has anyone figured out the other input? I have searched the net and the archives. There's very little info or discussion on this unit. Ed ___ 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] Question re neutrinos and GPS
Hi Bill -- Normally, they do close the loop at the end of the trip by comparing the traveling standard again with the home reference. In the quartz days, you would use the difference to determine the daily drift over the length of the trip (assuming the oscillator didn't get bumped too hard) and you could take that into account in the calculations Tom described. Today closing the calculation with a traveling Cs is more of a sanity check that nothing went wrong. John On Jan 8, 2012, at 12:55 PM, Bill Hawkins b...@iaxs.net wrote: Tom, I had to look up traveling clock synchronization to get a better understanding, and found this link: http://www.newtonphysics.on.ca/einstein/chapter9.html The idea that Qz (time on the quartz clock, no?) drops out in the subtraction seems to me to require Qz to be invariant. That seems beyond the capability of quartz at the required error of one microsecond during the many hours that it will take to transport Q between CERN and LNGS. Plenty of time for cracks to propagate or chips fall off. Why do you say we can ignore such effects? Thanks for any enlightenment. Bill Hawkins -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Van Baak Sent: Sunday, January 08, 2012 9:11 AM To: iov...@inwind.it Cc: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Question re neutrinos and GPS what about swapping the Cs clocks between CERN and LNGS without re- synchronizing them, and repeating the neutrino test? Antonio I8IOV Right, typically when you perform a traveling clock experiment you don't touch the clocks -- you don't need to synchronize or resynchronize anything. The key point is the difference in time from A to B, or A to B to A. This is accomplished with a time interval counter and you do the subtraction with a calculator. Imagine that you have two Rb in your house and wish to compare their times. If they are too far apart to use a long cable, one trick is to use a traveling quartz clock and TIC. You measure Rb1-Qz and then walk to the other clock in order to measure Rb2-Qz. Ignoring effects like drift in quartz or counter, the time of the quartz drops out of the calculation of Rb2-Rb1. Make sense? So there's no mathematical requirement for synchronization of the traveling clock. And there's also a practical reason why you don't precisely synchronize or resynchronize -- most Cs have a 100 ns granularity on their 1PPS sync input. /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. ___ 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] Question re neutrinos and GPS
Hi Bill, On 01/08/2012 06:55 PM, Bill Hawkins wrote: Tom, I had to look up traveling clock synchronization to get a better understanding, and found this link: http://www.newtonphysics.on.ca/einstein/chapter9.html The idea that Qz (time on the quartz clock, no?) drops out in the subtraction seems to me to require Qz to be invariant. That seems beyond the capability of quartz at the required error of one microsecond during the many hours that it will take to transport Q between CERN and LNGS. Plenty of time for cracks to propagate or chips fall off. Why do you say we can ignore such effects? Thanks for any enlightenment. During the expected 12 hour drive the systematic effects and random noise needs to be well contained, to reach the target of below 10 ns effect. This calls for metrology grade cesiums or even hydrogen clocks. We assume it does drift in phase, and that drift if indeed a concern in order to achieve the goal. A stop on the way to compare clocks is being considered. 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] HP Z3817A Reverse Engineering
OK, I wasn't able to find anything else. Moreover the STLN4096A seems to have a Rb oscillator now from the usual 'bay vendor... so seems confusing as the Z3817A may be the E1938A mounted on the PCB that can discipline it or it is another type of unit or whatever else. No picture found until now using google. Is the Z3817A like the fig.1 picture you can find here: http://www.prc68.com/I/HPE1938.shtml ? On Sun, Jan 8, 2012 at 6:57 PM, Ed Palmer ed_pal...@sasktel.net wrote: Hi Azelio, Thanks, but I already found that. I've moved quite a bit beyond that. That message was one of the few in the archives that had any significant info on this unit. For some reason, I find that surprising. Ed On 1/8/2012 11:33 AM, Azelio Boriani wrote: Have you already this? On the TIB (P1) DB-25 connector, I'm fairly confident about these: V+ pins 1 and 21 V- pins 8 and 25 10MHz #1 pins 2/15 xfmr coupled, ~4.6V into 1M 10MHz #2 pins 23/16 xfmr coupled, ~4.6V into 1M 1PPS pin 14 Supply voltage is dictated by Lucent DC-DC converter. Input is 18-36V, 1.9A. Still chasing down the other pins. Currently I am working on a possible disciplining input: input of some kind to U6/3 via 100 ohms pin 18, prob. diff with 4 input of some kind to U6/2 via 100 ohms pin 4, prob. diff with 18 The MMI (J1) DB-9 connector is RS-232, 9600baud, 8n1 and runs a a familiar SCPI interface. On Sun, Jan 8, 2012 at 6:20 PM, Ed Palmered_pal...@sasktel.net wrote: I recently purchased a Motorola STLN4096A with the HP E1938A oscillator. I bought it for the oscillator only. Then I got intrigued by the HP Z3817A GPSDO that's included. I've reverse engineered most of it and I've got it running. The 1 PPS is really good ( 1000 measurements, Std. Dev. of200 ps, min to max range of1.5 ns) and the HUP is very slowly dropping (currently at 13 us after ~1.5 days) as the oscillator works out the kinks after it's long sleep. It's dropping much slower than my Z3801A did when I first turned it on. There's one input that I haven't been able to figure out. I've got data in and 1 PPS in from the GPS receiver. Everything seems to be working so I'm at a loss what that the other input could be for. There are no clues to it's function because it appears to go into one of the Xilinx chips. Does anyone have any more info on the unit? Has anyone figured out the other input? I have searched the net and the archives. There's very little info or discussion on this unit. Ed ___ 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] Free bare board for Shera controller
The one from AA Engineering as shown in QST. With the instruction sheet, in the plastic sleeve. At least 10 years old (judging from the stratigraphy where I found it in the garage) First one to send me their address, I'll stick it in an envelope and mail it to you. Weighs 46g or 1 5/8 oz, so if you are not in the US, tell me how much postage to put on. Jim Lux ___ 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] Ebay FE-5680A Rb: Connections and Features
On Sun, Jan 8, 2012 at 7:49 AM, gandal...@aol.com wrote: Hi Roy If your unit is generating an output as you report, without 5 volts to pin 4, then I'd leave well alone. On the current batches of cheaper units, that do require a 5 volt supply to pin 4, they won't lock or provide an output without it. If you look inside, on some units there is a voltage regulator and on other units there are bare solder pads where the regulator and some capacitors would go.My guess is that if you got the bare pads you need to supply 5V. The reverse may not be true, I've read a report of a regulator that was installed but disconnected. I think these FE5680 units were all built to customer specs and each batch of a few thousand units is different. I wish there were some rule that when you change a product to have to change the part number but there is no such rule 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] Free bare board for Shera controller
John M. Franke WA4WDL 4500 Ibis Ct. Portsmouth, VA 23703 -- From: Jim Lux jim...@earthlink.net Sent: Sunday, January 08, 2012 1:33 PM To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: [time-nuts] Free bare board for Shera controller The one from AA Engineering as shown in QST. With the instruction sheet, in the plastic sleeve. At least 10 years old (judging from the stratigraphy where I found it in the garage) First one to send me their address, I'll stick it in an envelope and mail it to you. Weighs 46g or 1 5/8 oz, so if you are not in the US, tell me how much postage to put on. Jim Lux ___ 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] Free bare board for Shera controller
On 1/8/12 10:33 AM, Jim Lux wrote: The one from AA Engineering as shown in QST. With the instruction sheet, in the plastic sleeve. At least 10 years old (judging from the stratigraphy where I found it in the garage) First one to send me their address, I'll stick it in an envelope and mail it to you. we have a winner! less than 10 minutes. Congratulations Don. It's going in the mailbox now. ___ 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] Z3801A EFC error
On 01/02/2012 09:28 PM, Azelio Boriani wrote: On the usual paybay site there are available some Z3815 with the E1938 oscillator. I have bought one and found the shielding of the Furuno GT74 GPS heavily rusted. Fortunately it is perfectly working and the seller says all are that way. It was the only item found with that type of OCXO. I have found very little information on the Furuno GT74 receiver. Anyone having the usal manual stuff for it? 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] HP Z3817A Reverse Engineering
On 1/8/2012 12:19 PM, Azelio Boriani wrote: OK, I wasn't able to find anything else. Moreover the STLN4096A seems to have a Rb oscillator now from the usual 'bay vendor... so seems confusing as the Z3817A may be the E1938A mounted on the PCB that can discipline it or it is another type of unit or whatever else. No picture found until now using google. Yes, I agree that it's odd. It appears that Motorola had the same part number for both the OCXO-equipped and the Rubidium-equipped oscillators. Is the Z3817A like the fig.1 picture you can find here: http://www.prc68.com/I/HPE1938.shtml ? No, the E1938A oscillator is the entire board shown on that page. The board is the controller for the oscillator. Without the board, I think that all you've got is a nice paperweight. A while ago on the auction site, a vendor was selling just the crystal enclosure (the silver disk). I wondered if it was even possible to put the enclosure on another controller or if the controller contained some tuning parameters that were specific to the enclosure. He sold a few, did any time-nuts buy them? Anything to report? I forgot to take pictures when I had the unit apart, but the STLN4096A consists of the E1938A oscillator, a processor board, and a power supply board. Here's what the OCXO version looks like from the outside: http://gzwg.blogspot.com/2009/04/motorola-stln4096a-hight-remote.html Actually, mine looked quite a bit worse than that one, but that's another story. Just for completeness, here's what the Rubidium version looks like: http://gzwg.blogspot.com/2011/11/motorola-stln4096a-rubidium-oscillator.html Ed On Sun, Jan 8, 2012 at 6:57 PM, Ed Palmered_pal...@sasktel.net wrote: Hi Azelio, Thanks, but I already found that. I've moved quite a bit beyond that. That message was one of the few in the archives that had any significant info on this unit. For some reason, I find that surprising. Ed On 1/8/2012 11:33 AM, Azelio Boriani wrote: Have you already this? On the TIB (P1) DB-25 connector, I'm fairly confident about these: V+ pins 1 and 21 V- pins 8 and 25 10MHz #1 pins 2/15 xfmr coupled, ~4.6V into 1M 10MHz #2 pins 23/16 xfmr coupled, ~4.6V into 1M 1PPS pin 14 Supply voltage is dictated by Lucent DC-DC converter. Input is 18-36V, 1.9A. Still chasing down the other pins. Currently I am working on a possible disciplining input: input of some kind to U6/3 via 100 ohms pin 18, prob. diff with 4 input of some kind to U6/2 via 100 ohms pin 4, prob. diff with 18 The MMI (J1) DB-9 connector is RS-232, 9600baud, 8n1 and runs a a familiar SCPI interface. On Sun, Jan 8, 2012 at 6:20 PM, Ed Palmered_pal...@sasktel.net wrote: I recently purchased a Motorola STLN4096A with the HP E1938A oscillator. I bought it for the oscillator only. Then I got intrigued by the HP Z3817A GPSDO that's included. I've reverse engineered most of it and I've got it running. The 1 PPS is really good (1000 measurements, Std. Dev. of200 ps, min to max range of1.5 ns) and the HUP is very slowly dropping (currently at 13 us after ~1.5 days) as the oscillator works out the kinks after it's long sleep. It's dropping much slower than my Z3801A did when I first turned it on. There's one input that I haven't been able to figure out. I've got data in and 1 PPS in from the GPS receiver. Everything seems to be working so I'm at a loss what that the other input could be for. There are no clues to it's function because it appears to go into one of the Xilinx chips. Does anyone have any more info on the unit? Has anyone figured out the other input? I have searched the net and the archives. There's very little info or discussion on this unit. Ed ___ 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] Z3801A EFC error
I found the gt74 gps to be lacking in performance in my Z3815. Sorry, no data sheet for it. I simply cut the 1pps output cable, and spliced a ublox receiver 1pps output into it. Then I split the antenna feed to both gps and found 3.3V somewhere for the ublox gps. Works like a charm, z3815 firmware is happy talking to the Furuno, but timing and sensitivity is much better now from the ublox.. Even with a navigation receiver. Sorry, don't remember what pins where 1pps or power, but that's easy to find with a multimeter. Btw: the Z3815 output is very noisy for some reason. Hp did not do a good job on utilizing the E1938 performance here... Said On Jan 8, 2012, at 11:22, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 01/02/2012 09:28 PM, Azelio Boriani wrote: On the usual paybay site there are available some Z3815 with the E1938 oscillator. I have bought one and found the shielding of the Furuno GT74 GPS heavily rusted. Fortunately it is perfectly working and the seller says all are that way. It was the only item found with that type of OCXO. I have found very little information on the Furuno GT74 receiver. Anyone having the usal manual stuff for it? 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.
[time-nuts] Internal 5 volt switching regulator on some non-programmable FE-5680A's
Hello, After posting a few days ago about one of my '5680A's having the voltage converter installed - but not connected - I've done a bit of reverse-engineering and sleuthing around and (probably) have a fairly complete picture of what it would take to populate that section of the board. That information may be found here: http://ka7oei.com/10_MHz_Rubidium_FE-5680A.html This page is a work in progress, using my LPRO-101 page as a template and unashamedly stealing a good chunk of its content - most of which is directly applicable, anyway! Note that I haven't done the board population myself and there *may* be additional jumpers that need to be added/removed - or, as I suggest, one could avoid that problem and simply connect to known V+ and +5 volt points instead. If you happen to have one of those boards with the installed (but not connected) regulator, information is also included on which two jumpers I needed to add to enable it: Again, YMMV, DNTHFB, etc... If anyone populates their own board, please let me know how it worked out. I add this mostly out of interest expressed by a few others that emailed me. It's no doubt far easier/cheaper to simply add an outboard 7805 (or switching converter) than populate the board, but hey, why not? 73, Clint KA7OEI ___ 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] Internal 5 volt switching regulator on some non-programmable FE-5680A's
On Sun, Jan 8, 2012 at 1:51 PM, Clint Turner tur...@ussc.com wrote: Hello, After posting a few days ago about one of my '5680A's having the voltage converter installed - but not connected - I've done a bit of reverse-engineering and sleuthing around and (probably) have a fairly complete picture of what it would take to populate that section of the board. That information may be found here: http://ka7oei.com/10_MHz_**Rubidium_FE-5680A.htmlhttp://ka7oei.com/10_MHz_Rubidium_FE-5680A.html This page is a work in progress, using my LPRO-101 page as a template and unashamedly stealing a good chunk of its content - most of which is directly applicable, anyway! Are you sure about those resistor values? They look like 5.11K and 5.62K (standard 1% values) to me. Orin, KJ7HQ. ___ 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] Question re neutrinos and GPS
The idea that Qz (time on the quartz clock, no?) drops out in the subtraction seems to me to require Qz to be invariant. Hi Bill, You might be making this more complicated intended. Antonio was asking about *resynchronizing* clocks. Here's another example. You're at home at 7:45 AM and see that your wristwatch is 7 minutes ahead of your kitchen clock. You get to work at 8:30 AM and notice that your wristwatch is 5 minutes ahead of your office clock. What conclusions can you reasonably make from this? Unless your wristwatch is really sick, the simple conclusion is that your home and work clocks differ by 2 minutes. You have used your wristwatch for time transfer. But now here's the good part. Notice that it doesn't matter what time you actually left home or what time you got to work. It also doesn't matter if your wristwatch is ahead or behind or spot on. Your wristwatch does not have to be accurate; yet it was still usable for remote clock comparison. Notice also that you did not have to synchronize your wristwatch at home or resynchronize it at work. All you needed was two measurements; the 2 minute conclusion is the difference of two time differences. So that's the point I was making. The actual time displayed by the portable clock drops out of the calculation. You get a nice time interval measurement without having to worry about time. This is the beauty of differences of differences. It's why ADEV is immune from phase or frequency offsets, etc. So remote clock comparison using a portable clock works even if none of the three clocks is accurate. Note the accuracy of the measurement (think error bars) is a function of their stability; in this example, the TDEV at tau 45 minutes. /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] Internal 5 volt switching regulator on some non-programmable FE-5680A's
On Sun, 8 Jan 2012 14:23:02 -0800, Orin Eman orin.e...@gmail.com wrote: On Sun, Jan 8, 2012 at 1:51 PM, Clint Turner tur...@ussc.com wrote: Hello, After posting a few days ago about one of my '5680A's having the voltage converter installed - but not connected - I've done a bit of reverse-engineering and sleuthing around and (probably) have a fairly complete picture of what it would take to populate that section of the board. That information may be found here: http://ka7oei.com/10_MHz_**Rubidium_FE-5680A.htmlhttp://ka7oei.com/10_MHz_Rubidium_FE-5680A.html This page is a work in progress, using my LPRO-101 page as a template and unashamedly stealing a good chunk of its content - most of which is directly applicable, anyway! Are you sure about those resistor values? They look like 5.11K and 5.62K (standard 1% values) to me. I agree. Besides not requiring rare and expensive 4 significant digit precision resistors which just happen to match the marking of the standard 1% resistors, the nonstandard 12.95K and 11.15K on the schematic would yield 5.23 volts. 5.62K and 5.11K will yield 5.08 volts from the nominal 2.42 volt reference on the LT1376. The 5 volt resistor selection in the data sheet would have been closer but maybe they wanted the extra 7 millivolts or were compensating for the feedback bias pin current. If noise was so important I wonder why they did not use a lower noise switching regulator or the LT1375 which supports oscillator synchronization. ___ 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] Question re neutrinos and GPS
On 1/8/2012 5:54 PM, Tom Van Baak wrote: Here's another example. You're at home at 7:45 AM and see that your wristwatch is 7 minutes ahead of your kitchen clock. You get to work at 8:30 AM and notice that your wristwatch is 5 minutes ahead of your office clock. What conclusions can you reasonably make from this? You shouldn't be on this list. :-) ___ 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] HP Z3817A Reverse Engineering
Hi Ed, May I ask where did you get your STLN4096A and what you paid for it? Do they have any more? My E1938 recently crapped out. If I put a substitute 10MHz near the first buffer, the PIC processor comes alive, then I can remove the 10MHz and it begins to oscillate on it's own. I can quickly recycle power and it still oscillates. Let it cool down and I need to repeat the stimulus procedure. Anybody have any ideas? Thanks, Bob - Original Message - From: Ed Palmer ed_pal...@sasktel.net To: Time-Nuts time-nuts@febo.com Sent: Sunday, January 08, 2012 12:20 PM Subject: [time-nuts] HP Z3817A Reverse Engineering I recently purchased a Motorola STLN4096A with the HP E1938A oscillator. I bought it for the oscillator only. Then I got intrigued by the HP Z3817A GPSDO that's included. I've reverse engineered most of it and I've got it running. The 1 PPS is really good ( 1000 measurements, Std. Dev. of 200 ps, min to max range of 1.5 ns) and the HUP is very slowly dropping (currently at 13 us after ~1.5 days) as the oscillator works out the kinks after it's long sleep. It's dropping much slower than my Z3801A did when I first turned it on. There's one input that I haven't been able to figure out. I've got data in and 1 PPS in from the GPS receiver. Everything seems to be working so I'm at a loss what that the other input could be for. There are no clues to it's function because it appears to go into one of the Xilinx chips. Does anyone have any more info on the unit? Has anyone figured out the other input? I have searched the net and the archives. There's very little info or discussion on this unit. Ed ___ 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] manuals, anyone?
Magnus, You must have tried while I was working at fixing an issue with folders that have special characters, like ampersand and the plus sign +. It should be working now. If you still have problem, please feel free to email me again... There are other characters that are not accepted, but I normally try to eliminate them when I transfer the files. When I get a large batch like I did last Thursday, it is a fair amount of work to screen everything and rename if necessary, so I decided to fix the problem instead :) I am probably not done, but these two were the most frequent. Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Magnus Danielson mag...@rubidium.dyndns.org Date: Sun, 08 Jan 2012 16:09:51 To: shali...@gmail.com; Magnus Danielsonmag...@rubidium.dyndns.org Subject: Re: [time-nuts] manuals, anyone? On 08/04/2011 09:24 PM, shali...@gmail.com wrote: I have about 25 GB of manuals on my web site www.ko4bb.com, with new uploads almost daily, and unlimited storage space. Feel free to upload to your heart content :) Speaking of which, your Rohde__Schwarz link does not link to your RohdeSchwarz directory. Was looking for a service manual to help a friend. Cheers, Magnus Didier KO4BB Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: li...@lazygranch.com Sender: time-nuts-boun...@febo.com Date: Thu, 4 Aug 2011 16:39:05 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: li...@lazygranch.com, Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] manuals, anyone? I used BAMA as an example. If there really is a problem storing manuals online, it wouldn't be difficult to start a similar website. I'm going to check with a contact I have at archive.org to see if they want to store manuals. I have over 20GB of manuals on my desktop. -Original Message- From: Dave Mdgmin...@mediacombb.net Sender: time-nuts-boun...@febo.com Date: Thu, 4 Aug 2011 11:08:46 To:time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] manuals, anyone? I think a simple solution is anyone that gets a free manual has to scan it and upload it to BAMA or some other free manual website. Nice in theory. Unlikely to work in practice, IMO. BAMA is a laudible effort, but in practice many documents aree not well scanned and some are nearly useless. It is unrealistic to expect one person to scan filing cabinets worth of manuals, but to spread the task around makes sense. Dave has done it. YMMV, -John BAMA is kinda strange nowadays. According to the note on the edebris mirror page, the main BAMA site has been down for repairs and upgrades since 9/17/2009; almost 2 years ago. Will the main site ever come back online, or has it been written off permanently? Also, as I remember, there was a note somewhere on the site that the owner(s) of the BAMA site were no longer accepting manuals for test equipment... only real boat anchors such as tube type radios, ham gear, etc. Am I remembering correctly, or was there a different restriction or has the restriction been removed? I know that I tried to upload a couple Tektronix manuals that I had scanned, but they never showed up on the site. David dgminala at mediacombb dot net ___ 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] Simple GPSDO
On 12/31/2011 08:15 AM, Charles P. Steinmetz wrote: I know the thread began with a request for a simple DIY GPSDO, and this may not be quite as simple as some might like. However, PPS discipline is generally the simplest and most universal scheme from the standpoint of interfacing to whatever GPS engine one has available. The PRS10 has a clever system for PPS disclipine, using time-tagging for phase detection, that mitigates the usual shortcomings of PPS discipline and should be suitable for PIC/FPGA implementation. As implemented by SRS, the discipline parameters are more than sufficiently adjustable for any need. For a homebrew version, the VCO would be the quartz VCXO or Rb of your choice. The pre-filter (which is selectable in the PRS10) would be a great help in dealing with the jitter in a GPS PPS signal. PPS locking is discussed at pp. 14-18 of the 2003 and 2005 manuals. (The manuals and Rev. H schematic are readily available on the web.) The feedback is really just the PPS counter 0-999 modeled, and any interpolation can be added without loss of generality. The time-tagging is thus just sampling the state of the counter, and optionally add interpolator value. You also want to have a quick-align that will reset the counter to quickly jump into phase, before entering normal loop. That will save you a lot of lock-in time as the phase will be in line... and worst-case phase error can be half a second, so worst-case will 5 milion cycles needs to be skewed, and doing that on the oscillator isn't very time-efficient and causes for one hell of a initial phase error. The pre-filtering exponential averager and PI-regulator is very cheap to implement in a PIC, AVR or whatever. Just leave enough bits in there. I think a simple CPLD or FPGA will pull it off. You need 24 bit for counting, 24 bit for time-stamp and a few more for logic. You can compress the range for the time-stamp, as you only need to know too high, too low and a fairly small in-range value range. If you allow for +/- 10 us error you only need 200 values... so there is only 8 bits. 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] manuals, anyone?
On 01/09/2012 02:25 AM, shali...@gmail.com wrote: Magnus, You must have tried while I was working at fixing an issue with folders that have special characters, like ampersand and the plus sign +. It should be working now. If you still have problem, please feel free to email me again... There are other characters that are not accepted, but I normally try to eliminate them when I transfer the files. When I get a large batch like I did last Thursday, it is a fair amount of work to screen everything and rename if necessary, so I decided to fix the problem instead :) I am probably not done, but these two were the most frequent. It works now. Just wanted to make you aware. 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] HP Z3817A Reverse Engineering
Hi Bob, I bought mine on eBay from fluke.l for about $114 (including shipping). I don't know if he has any more. He didn't get positive feedback from me. His pictures showed a reasonable, used unit. The unit he shipped was dented badly enough that it was slightly crushed and appeared to have been out in the rain. It does work, but the E1938 seems to be taking a long time to settle down. I hope the crystal wasn't damaged when it took the hit that dented the case. There is no physical damage to any of the boards. I've dealt with him before and was surprised and disappointed that he didn't describe the condition better. Buyer beware. As for your 'lazy' E1938, have you grabbed the schematics and circuit description from http://www.prc68.com/I/HPE1938.shtml ? Ed On 1/8/2012 5:58 PM, Robert Benward wrote: Hi Ed, May I ask where did you get your STLN4096A and what you paid for it? Do they have any more? My E1938 recently crapped out. If I put a substitute 10MHz near the first buffer, the PIC processor comes alive, then I can remove the 10MHz and it begins to oscillate on it's own. I can quickly recycle power and it still oscillates. Let it cool down and I need to repeat the stimulus procedure. Anybody have any ideas? Thanks, Bob - Original Message - From: Ed Palmer ed_pal...@sasktel.net To: Time-Nuts time-nuts@febo.com Sent: Sunday, January 08, 2012 12:20 PM Subject: [time-nuts] HP Z3817A Reverse Engineering I recently purchased a Motorola STLN4096A with the HP E1938A oscillator. I bought it for the oscillator only. Then I got intrigued by the HP Z3817A GPSDO that's included. I've reverse engineered most of it and I've got it running. The 1 PPS is really good ( 1000 measurements, Std. Dev. of 200 ps, min to max range of 1.5 ns) and the HUP is very slowly dropping (currently at 13 us after ~1.5 days) as the oscillator works out the kinks after it's long sleep. It's dropping much slower than my Z3801A did when I first turned it on. There's one input that I haven't been able to figure out. I've got data in and 1 PPS in from the GPS receiver. Everything seems to be working so I'm at a loss what that the other input could be for. There are no clues to it's function because it appears to go into one of the Xilinx chips. Does anyone have any more info on the unit? Has anyone figured out the other input? I have searched the net and the archives. There's very little info or discussion on this unit. Ed ___ 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] Internal 5 volt switching regulator on some non-programmable FE-5680A's
Hi, Are you sure about those resistor values? They look like 5.11K and 5.62K (standard 1% values) to me. Whoops - you are right: In squinting at the board I'd thought about turning the thing 180 degrees since the numbers look believable either way! These two 5k-ish values are more in line with the values called out in the data sheet for the '1376 (4.99k/5.36k). I look forward to hearing from someone who might take on populating these components on the board and what they find. 73, Clint KA7OEI ___ 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] Simple GPSDO
On Mon, 09 Jan 2012 03:05:36 +0100, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 12/31/2011 08:15 AM, Charles P. Steinmetz wrote: I know the thread began with a request for a simple DIY GPSDO, and this may not be quite as simple as some might like. However, PPS discipline is generally the simplest and most universal scheme from the standpoint of interfacing to whatever GPS engine one has available. The PRS10 has a clever system for PPS disclipine, using time-tagging for phase detection, that mitigates the usual shortcomings of PPS discipline and should be suitable for PIC/FPGA implementation. As implemented by SRS, the discipline parameters are more than sufficiently adjustable for any need. For a homebrew version, the VCO would be the quartz VCXO or Rb of your choice. The pre-filter (which is selectable in the PRS10) would be a great help in dealing with the jitter in a GPS PPS signal. PPS locking is discussed at pp. 14-18 of the 2003 and 2005 manuals. (The manuals and Rev. H schematic are readily available on the web.) The feedback is really just the PPS counter 0-999 modeled, and any interpolation can be added without loss of generality. The time-tagging is thus just sampling the state of the counter, and optionally add interpolator value. You also want to have a quick-align that will reset the counter to quickly jump into phase, before entering normal loop. That will save you a lot of lock-in time as the phase will be in line... and worst-case phase error can be half a second, so worst-case will 5 milion cycles needs to be skewed, and doing that on the oscillator isn't very time-efficient and causes for one hell of a initial phase error. The design published in QST a couple years ago divided 5 MHz oscillator by 16 to about 312 kHz and then did the phase comparison. http://www.rt66.com/~shera/QST_GPS.pdf The pre-filtering exponential averager and PI-regulator is very cheap to implement in a PIC, AVR or whatever. Just leave enough bits in there. I think a simple CPLD or FPGA will pull it off. You need 24 bit for counting, 24 bit for time-stamp and a few more for logic. You can compress the range for the time-stamp, as you only need to know too high, too low and a fairly small in-range value range. If you allow for +/- 10 us error you only need 200 values... so there is only 8 bits. For a simple design after frequency locking, I am leaning more toward triggering a time to voltage converter off of the PPS output to measure the phase and feeding that directly into a charge to voltage integrator to adjust the oscillator. The only digital state change is from frequency to phase locking. In a complex design, I would use the same time to voltage conversion but include a calibration cycle and digitally filter in a PIC or similar. That would also allow direct evaluation of the PPS source. ___ 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] Subject: Re: Question re neutrinos and GPS
On 1/8/2012 5:54 PM, Tom Van Baak wrote: Here's another example. You're at home at 7:45 AM and see that your wristwatch is 7 minutes ahead of your kitchen clock. You get to work at 8:30 AM and notice that your wristwatch is 5 minutes ahead of your office clock. What conclusions can you reasonably make from this? You shouldn't ride your bike so fast Mr Tompkins! (apologies to Dr Gamow) Rob Culver VK5RC ___ 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.
