Re: [time-nuts] FE-5680A dumb question...
The manual is for a similar unit with the same part number. On this unit (I was going to be sarcastic and say Its the pin with the 10MHz sine wave on it but here it the pinout. I get about 2V peak to peak when loaded with a 10X scope probe only 1 +15V 2 return for #1 3 lock.unlock 4 +5V 5 gnd 6 N/C (but I see a tiny ~60MHz sine-like wave 7 10MHZ output 8 rs232 Rx 9 rs232 Tx On Tue, Jan 3, 2012 at 5:58 PM, Brian, WA1ZMS wa1...@att.net wrote: My E-bay FE-5680A finally arrived. (4weeks later) Of the pins on the DB-9 connector, which one is the RF output? The manual only talks about an SMA output. I know this has been talked about before, but I cannot find the thread. Thanks in advance sorry for bandwidth, -Brian, WA1ZMS ___ time-nuts mailing 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] Navsync CW-12 GPS Board - I don't believe it!!
I compared the OCXO output to the 10 MHz output of both a Z3801A and a Tbolt and discovered that the CW-12's 10 MHz output is about 1.5e-11 (i.e. 1.5e-4 Hz) low in frequency. I emailed Navsync and they replied: The CW12 Motorola Binary and NMEA versions both do not phase align the frequency output so the long term drift that Ed is seeing is expected. Is there a timing version that does the right thing? Incredible. It's 'steered by the GPS receiver' - that's a direct quote from the data sheet and the user manual - but it's not quite on frequency and that's fine with them. Is it consistently off that much, or does it wander around the right answer? (perhaps because there is a small dead band in the phase detector) -- These are my opinions, not necessarily my employer's. 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] FE-5680A dumb question...
Le 04/01/2012 02:58, Brian, WA1ZMS a écrit : My E-bay FE-5680A finally arrived. (4weeks later) Of the pins on the DB-9 connector, which one is the RF output? The manual only talks about an SMA output. It may depend on the version as there are lots. If you have the cheapo 30352-1 part like me, the pinout is : pin1 power +15 to +18v pin2 ground pin3 lock/unlock - active when unlocked pin4 power +5v pin5 ground pin7 RF out* *** * ** * ___ time-nuts mailing 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] FE-5680A dumb question...
Hi Brian. Taking the list concensus and confirming it on my recently arrived '5680A, the pinout is as follows: 1. +15V (1500mA cold: 800mA hot) 2. Gnd 3. Rb Lock (lock = low) 4. +5V (~85mA) 5. Gnd 6. 1PPS (high until Rb Lock goes low) 7. 10Mhz 8. RS323-RX 9. RS232-TX These pinouts are not consistant across the FE-5680A range, but seems good for the 'current batch' of cheap units coming out of china. Cheers, ian Date: Tue, 3 Jan 2012 20:58:10 -0500 From: Brian, WA1ZMS wa1...@att.net To: Time-Nuts time-nuts@febo.com Subject: [time-nuts] FE-5680A dumb question... Message-ID: 01ccca84$4ff2d570$efd88050$@att.net Content-Type: text/plain; charset=us-ascii My E-bay FE-5680A finally arrived. (4weeks later) Of the pins on the DB-9 connector, which one is the RF output? The manual only talks about an SMA output. I know this has been talked about before, but I cannot find the thread. Thanks in advance sorry for bandwidth, -Brian, WA1ZMS ___ time-nuts mailing 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] Navsync CW-12 GPS Board - I don't believe it!!
These Conner Winfield (Navsync) parts are not GPS Disciplined Oscillators, many folks are initially fooled by this. They use digital phase hopping techniques to generate something close to 10MHz. You can see the 10MHz 100ns phase jump around on a scope. I believe their FTS250 and 125 modules use this output to drive a VCXO cleanup oscillator to try to remove the phase jumps, phase noise, and spurs. From their literature: This ... module has an onboard, programmable NCO oscillator that outputs a synthesized frequency up to 30MHz steered by a GPS receiver So it's a noisy digitally steered NCO, not a clean phase locked analog oscillator. The frequency error can be up to +/-100ppb according to their literature while the unit is trying to align itself to GPS (that's a massive drift of 100ns per second!) I believe the uBlox 6T frequency output is generated in a similar manner. Many folks try these GPS NCO's because they are cheaper than real GPSDO's and seem to work similarly, then find out they don't perform as well... In a message dated 1/4/2012 00:32:33 Pacific Standard Time, hmur...@megapathdsl.net writes: I compared the OCXO output to the 10 MHz output of both a Z3801A and a Tbolt and discovered that the CW-12's 10 MHz output is about 1.5e-11 (i.e. 1.5e-4 Hz) low in frequency. I emailed Navsync and they replied: The CW12 Motorola Binary and NMEA versions both do not phase align the frequency output so the long term drift that Ed is seeing is expected. Is there a timing version that does the right thing? Incredible. It's 'steered by the GPS receiver' - that's a direct quote from the data sheet and the user manual - but it's not quite on frequency and that's fine with them. Is it consistently off that much, or does it wander around the right answer? (perhaps because there is a small dead band in the phase detector) -- These are my opinions, not necessarily my employer's. 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] crunching numbers from XOR phase detector
Neat. Thanks for sharing. With a XOR, you can't tell which input is higher frequency. I think you can fix that with a second XOR and a delay line. I think 90 degrees of delay will provide the most information. At 10 MHz, that's 25 ns. I think that's about 15 feet of good coax. -- These are my opinions, not necessarily my employer's. 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] Navsync CW-12 GPS Board - I don't believe it!!
You are right. We use the CW12 (timing version) and it behaves as you depicted. Of course there is also no holdover on its 10MHz output. Only the FTS125 (and similar) have first a fixed OCXO to drive the GPS receiver and then an OCXO to be aligned with the 10MHz to have a real 10MHz with holdover BUT, curiously enough, PPS comes always from the GPS receiver. Never tested the 10MHz being lower... now I'll try from the CW12 and from the FTS125. On Wed, Jan 4, 2012 at 9:50 AM, saidj...@aol.com wrote: These Conner Winfield (Navsync) parts are not GPS Disciplined Oscillators, many folks are initially fooled by this. They use digital phase hopping techniques to generate something close to 10MHz. You can see the 10MHz 100ns phase jump around on a scope. I believe their FTS250 and 125 modules use this output to drive a VCXO cleanup oscillator to try to remove the phase jumps, phase noise, and spurs. From their literature: This ... module has an onboard, programmable NCO oscillator that outputs a synthesized frequency up to 30MHz steered by a GPS receiver So it's a noisy digitally steered NCO, not a clean phase locked analog oscillator. The frequency error can be up to +/-100ppb according to their literature while the unit is trying to align itself to GPS (that's a massive drift of 100ns per second!) I believe the uBlox 6T frequency output is generated in a similar manner. Many folks try these GPS NCO's because they are cheaper than real GPSDO's and seem to work similarly, then find out they don't perform as well... In a message dated 1/4/2012 00:32:33 Pacific Standard Time, hmur...@megapathdsl.net writes: I compared the OCXO output to the 10 MHz output of both a Z3801A and a Tbolt and discovered that the CW-12's 10 MHz output is about 1.5e-11 (i.e. 1.5e-4 Hz) low in frequency. I emailed Navsync and they replied: The CW12 Motorola Binary and NMEA versions both do not phase align the frequency output so the long term drift that Ed is seeing is expected. Is there a timing version that does the right thing? Incredible. It's 'steered by the GPS receiver' - that's a direct quote from the data sheet and the user manual - but it's not quite on frequency and that's fine with them. Is it consistently off that much, or does it wander around the right answer? (perhaps because there is a small dead band in the phase detector) -- These are my opinions, not necessarily my employer's. 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. ___ time-nuts mailing 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] crunching numbers from XOR phase detector
Le 04/01/2012 09:58, Hal Murray a écrit : Neat. Thanks for sharing. With a XOR, you can't tell which input is higher frequency. I think you can fix that with a second XOR and a delay line. I think 90 degrees of delay will provide the most information. At 10 MHz, that's 25 ns. I think that's about 15 feet of good coax. all that spaghetti made me wonder if you can get it on a chip . yes, it seems. ex EP8034, 200ns in tenths. there are others of course. ___ time-nuts mailing 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] crunching numbers from XOR phase detector (mike cook)
Neat. Thanks for sharing. With a XOR, you can't tell which input is higher frequency. I think you can fix that with a second XOR and a delay line. I think 90 degrees of delay will provide the most information. At 10 MHz, that's 25 ns. I think that's about 15 feet of good coax. all that spaghetti made me wonder if you can get it on a chip . yes, it seems. ex EP8034, 200ns in tenths. there are others of course. http://www.minicircuits.com/pdfs/JSPHS-12.pdf It's not digital. It is an alalog adjustable voltage controlled phase shifter. If you want to shift a relatively clean 10Mhz sine... ___ time-nuts mailing 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] crunching numbers from XOR phase detector
On Wed, 04 Jan 2012 00:58:24 -0800, Hal Murray hmur...@megapathdsl.net wrote: With a XOR, you can't tell which input is higher frequency. I think you can fix that with a second XOR and a delay line. I think 90 degrees of delay will provide the most information. At 10 MHz, that's 25 ns. I think that's about 15 feet of good coax. I was thinking of an added D flip-flop, D latch, or a 330 ohm 100 pF RC delay in front of a second XOR gate. ___ time-nuts mailing 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] Navsync CW-12 GPS Board - I don't believe it!!
On 1/4/2012 2:14 AM, Hal Murray wrote: I compared the OCXO output to the 10 MHz output of both a Z3801A and a Tbolt and discovered that the CW-12's 10 MHz output is about 1.5e-11 (i.e. 1.5e-4 Hz) low in frequency. I emailed Navsync and they replied: The CW12 Motorola Binary and NMEA versions both do not phase align the frequency output so the long term drift that Ed is seeing is expected. Is there a timing version that does the right thing? Unfortunately, this _is_ the timing version! Incredible. It's 'steered by the GPS receiver' - that's a direct quote from the data sheet and the user manual - but it's not quite on frequency and that's fine with them. Is it consistently off that much, or does it wander around the right answer? (perhaps because there is a small dead band in the phase detector) The frequency error is consistent. Superimposed on that error is the normal GPS wander that you see with every GPS receiver. 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] FE 5680a 3pay 36.89 includes shipping. Finally ordered one
Noticed that one of my 5680 units was a bit unstable at times. Reglued the crystal back on to the board and it it happy! 73, Bill, WA2DVU Cape May, NJ ons 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] Navsync CW-12 GPS Board - I don't believe it!!
I've never said that the CW12 was a GPSDO. What I expected to get was a noisy NCO that had an average frequency of 10 MHz. What I got was a worthless noise generator. What's the point of saying that it's steered by GPS when it's off-frequency. What does that even mean? Does it steer the frequency to keep the error constant? For some reason, this makes me think of the GPS systems that say Turn left now! when you're in the middle of a bridge. :-) Ed On 1/4/2012 2:50 AM, saidj...@aol.com wrote: These Conner Winfield (Navsync) parts are not GPS Disciplined Oscillators, many folks are initially fooled by this. They use digital phase hopping techniques to generate something close to 10MHz. You can see the 10MHz 100ns phase jump around on a scope. I believe their FTS250 and 125 modules use this output to drive a VCXO cleanup oscillator to try to remove the phase jumps, phase noise, and spurs. From their literature: This ... module has an onboard, programmable NCO oscillator that outputs a synthesized frequency up to 30MHz steered by a GPS receiver So it's a noisy digitally steered NCO, not a clean phase locked analog oscillator. The frequency error can be up to +/-100ppb according to their literature while the unit is trying to align itself to GPS (that's a massive drift of 100ns per second!) I believe the uBlox 6T frequency output is generated in a similar manner. Many folks try these GPS NCO's because they are cheaper than real GPSDO's and seem to work similarly, then find out they don't perform as well... In a message dated 1/4/2012 00:32:33 Pacific Standard Time, hmur...@megapathdsl.net writes: I compared the OCXO output to the 10 MHz output of both a Z3801A and a Tbolt and discovered that the CW-12's 10 MHz output is about 1.5e-11 (i.e.1.5e-4 Hz) low in frequency. I emailed Navsync and they replied: The CW12 Motorola Binary and NMEA versions both do not phase align the frequency output so the long term drift that Ed is seeing is expected. Is there a timing version that does the right thing? Incredible. It's 'steered by the GPS receiver' - that's a direct quote from the data sheet and the user manual - but it's not quite on frequency and that's fine with them. Is it consistently off that much, or does it wander around the right answer? (perhaps because there is a small dead band in the phase detector) ___ time-nuts mailing 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] Navsync CW-12 GPS Board - I don't believe it!!
On 1/4/2012 9:29 AM, Ed Palmer wrote: What's the point of saying that it's steered by GPS when it's off-frequency. What does that even mean? Does it steer the frequency to keep the error constant? If it's constant, maybe they just need to re-spec it as having a 9.985 MHz output. :-) ___ time-nuts mailing 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] OffsetGenerator
Moin Ulrich, On Sun, 25 Dec 2011 13:11:24 +0100 Ulrich Bangert df...@ulrich-bangert.de wrote: a) A clock shaper as designed by Bruce Griffiths based on a ADCMP600 that should work well to over 100 MHz. I had a short look at the schmeatics and something caught my eyes: On sheet 3 Input Buffers D10/C25 doesn't make sense to me. It looks like an input clamp, but it isn't. What is the purpose of this circuit? Attila Kinali -- Why does it take years to find the answers to the questions one should have asked long ago? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Navsync CW-12 GPS Board - I don't believe it!!
The output frequency is programmable: try $PRTHS,FRQD,xx.xxxcrlf where xx.xxx is the desired(?) frequency in MHz with 3 decimal places (they say for 10KHz set 0.010). Maybe the slight offset is due to the NCO based on the chipping rate of 10.23MHz: 10.23MHz/2^32*4198404003 is 9.783MHz On Wed, Jan 4, 2012 at 3:49 PM, Mike S mi...@flatsurface.com wrote: On 1/4/2012 9:29 AM, Ed Palmer wrote: What's the point of saying that it's steered by GPS when it's off-frequency. What does that even mean? Does it steer the frequency to keep the error constant? If it's constant, maybe they just need to re-spec it as having a 9.985 MHz output. :-) ___ time-nuts mailing 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] Navsync CW-12 GPS Board - I don't believe it!!
On 1/4/2012 8:49 AM, Mike S wrote: On 1/4/2012 9:29 AM, Ed Palmer wrote: What's the point of saying that it's steered by GPS when it's off-frequency. What does that even mean? Does it steer the frequency to keep the error constant? If it's constant, maybe they just need to re-spec it as having a 9.985 MHz output. :-) Ooo, it's a GPS steered offset generator! Now I get it! :-) 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] crunching numbers from XOR phase detector
At 10:16 AM + 1/4/12, time-nuts-requ...@febo.com wrote: Date: Wed, 04 Jan 2012 00:58:24 -0800 From: Hal Murray hmur...@megapathdsl.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] crunching numbers from XOR phase detector Message-ID: 20120104085824.8426e800...@ip-64-139-1-69.sjc.megapath.net Content-Type: text/plain; charset=us-ascii Neat. Thanks for sharing. With a XOR, you can't tell which input is higher frequency. I think you can fix that with a second XOR and a delay line. I think 90 degrees of delay will provide the most information. At 10 MHz, that's 25 ns. I think that's about 15 feet of good coax. Beware of teflon dielectric cable, as the teflon knee is centered around room temperature, making delay cables of teflon quite sensitive to slight changes in temperature. http://www.micro-coax.com/pages/technicalinfo/applications/27.asp Joe Gwinn ___ time-nuts mailing 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] Navsync CW-12 GPS Board - I don't believe it!!
On 1/4/2012 9:00 AM, Azelio Boriani wrote: The output frequency is programmable: try $PRTHS,FRQD,xx.xxxcrlf where xx.xxx is the desired(?) frequency in MHz with 3 decimal places (they say for 10KHz set 0.010). Unfortunately, the frequency is programmable only with the NMEA software load. I'm using the Motorola load. If I reflashed to the NMEA load I'd lose the TRAIM functionality. In any case, the setting doesn't have nearly enough resolution to correct such a small error. Maybe the slight offset is due to the NCO based on the chipping rate of 10.23MHz: 10.23MHz/2^32*4198404003 is 9.783MHz Your calculation gives an error of 2.17 mHz. I measured an error of .15 mHz. I tried playing with variations on your calculation but couldn't find one that fit. It would be interesting to find out why the error exists, but I don't think we will ever know for sure. 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] Navsync CW-12 GPS Board - I don't believe it!!
Yes, the error is greater... then maybe the clock of the NCO is not the chipping rate. In the FTS125 the clock for the RX is sourced by a 20MHz OFC5DJ3 fixed OCXO but this doesn't imply that the CW12 has a 20MHz clock... at the moment no other clue comes to mind. On Wed, Jan 4, 2012 at 5:35 PM, Ed Palmer ed_pal...@sasktel.net wrote: On 1/4/2012 9:00 AM, Azelio Boriani wrote: The output frequency is programmable: try $PRTHS,FRQD,xx.xxxcrlf where xx.xxx is the desired(?) frequency in MHz with 3 decimal places (they say for 10KHz set 0.010). Unfortunately, the frequency is programmable only with the NMEA software load. I'm using the Motorola load. If I reflashed to the NMEA load I'd lose the TRAIM functionality. In any case, the setting doesn't have nearly enough resolution to correct such a small error. Maybe the slight offset is due to the NCO based on the chipping rate of 10.23MHz: 10.23MHz/2^32*4198404003 is 9.783MHz Your calculation gives an error of 2.17 mHz. I measured an error of .15 mHz. I tried playing with variations on your calculation but couldn't find one that fit. It would be interesting to find out why the error exists, but I don't think we will ever know for sure. 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] Navsync CW-12 GPS Board - I don't believe it!!
Hi Ed, Since the oscillator is typically free-running in an NCO, and periodically corrected by phase drops to stay on frequency the error you are seeing may be caused be the offset in your crystal, combined with the limited digital resolution of the NCO trying to correct for this offset. If this is the case, your measured error would change with temperature. Does it do that? If yes, the NCO resolution is not fractionally corrected all the way. Replacing the on board Tcxo with an ocxo hand-tuned to the correct frequency would help, but that sort of defeats the purpose of the product.. Bye, Said Sent from my iPad On Jan 4, 2012, at 7:05, Ed Palmer ed_pal...@sasktel.net wrote: On 1/4/2012 8:49 AM, Mike S wrote: On 1/4/2012 9:29 AM, Ed Palmer wrote: What's the point of saying that it's steered by GPS when it's off-frequency. What does that even mean? Does it steer the frequency to keep the error constant? If it's constant, maybe they just need to re-spec it as having a 9.985 MHz output. :-) Ooo, it's a GPS steered offset generator! Now I get it! :-) 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] crunching numbers from XOR phase detector
On Wed, Jan 4, 2012 at 12:58 AM, Hal Murray hmur...@megapathdsl.net wrote: Neat. Thanks for sharing. With a XOR, you can't tell which input is higher frequency. I think you can fix that with a second XOR and a delay line. I think you can build a PFD or Phase Frequency Detector with three or four flip flops. This avoid using the delay line and works over a wide range. If I'm not mistaken there is a PFD inside the 74HC4046. It uses flip flops. Be sure to look at the 74HC type not the cd4046. The 75hc type works up to 18MHz. 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] Navsync CW-12 GPS Board - I don't believe it!!
Interesting...now i wonder how they can steer the frequency. Usually in C/A GPS receivers the oscillator is not corrected and any drift is accounted for in software: usually you see geographic coordinates out of the receiver. In the Motorola receiver they say the PPS has the granularity of the oscillator (and the negative sawtooth can be used to compensate and obtain greater precision) so no oscillator correction is necessary either: just place the rise of the PPS at the nearest clock transition (and the residual went in the previous sawtooh). Now to correct the frequency output of a CW12 without adjusting the clock the only way is to change the phase accumulator step: maybe the phase accumulator in the CW12 is greater than 32bit... On Wed, Jan 4, 2012 at 6:13 PM, Said Jackson saidj...@aol.com wrote: Hi Ed, Since the oscillator is typically free-running in an NCO, and periodically corrected by phase drops to stay on frequency the error you are seeing may be caused be the offset in your crystal, combined with the limited digital resolution of the NCO trying to correct for this offset. If this is the case, your measured error would change with temperature. Does it do that? If yes, the NCO resolution is not fractionally corrected all the way. Replacing the on board Tcxo with an ocxo hand-tuned to the correct frequency would help, but that sort of defeats the purpose of the product.. Bye, Said Sent from my iPad On Jan 4, 2012, at 7:05, Ed Palmer ed_pal...@sasktel.net wrote: On 1/4/2012 8:49 AM, Mike S wrote: On 1/4/2012 9:29 AM, Ed Palmer wrote: What's the point of saying that it's steered by GPS when it's off-frequency. What does that even mean? Does it steer the frequency to keep the error constant? If it's constant, maybe they just need to re-spec it as having a 9.985 MHz output. :-) Ooo, it's a GPS steered offset generator! Now I get it! :-) 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] crunching numbers from XOR phase detector
You're right there are 3 phase detectors in the 4046: RS and JK flip-flops and and XOR gate. On Wed, Jan 4, 2012 at 6:21 PM, Chris Albertson albertson.ch...@gmail.comwrote: On Wed, Jan 4, 2012 at 12:58 AM, Hal Murray hmur...@megapathdsl.net wrote: Neat. Thanks for sharing. With a XOR, you can't tell which input is higher frequency. I think you can fix that with a second XOR and a delay line. I think you can build a PFD or Phase Frequency Detector with three or four flip flops. This avoid using the delay line and works over a wide range. If I'm not mistaken there is a PFD inside the 74HC4046. It uses flip flops. Be sure to look at the 74HC type not the cd4046. The 75hc type works up to 18MHz. 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] crunching numbers from XOR phase detector
Be very careful of the FPD in the 4046. It has a dead-zone when the phase error is at or very close to zero. Some versions of the chip claim to have improved that dead-zone. But it's still there to some degree, at least in all the versions I have tried. -Brian, WA1ZMS - Original Message From: Chris Albertson albertson.ch...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wed, January 4, 2012 12:21:06 PM Subject: Re: [time-nuts] crunching numbers from XOR phase detector On Wed, Jan 4, 2012 at 12:58 AM, Hal Murray hmur...@megapathdsl.net wrote: Neat. Thanks for sharing. With a XOR, you can't tell which input is higher frequency. I think you can fix that with a second XOR and a delay line. I think you can build a PFD or Phase Frequency Detector with three or four flip flops. This avoid using the delay line and works over a wide range. If I'm not mistaken there is a PFD inside the 74HC4046. It uses flip flops. Be sure to look at the 74HC type not the cd4046. The 75hc type works up to 18MHz. 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] Efratom FRK - no 10Mhz oscillator
Thanks, all, for your recent help on my Efratom. I finally got it operational. The crystal-holder in the [hot] OCXO was bad; one pin looked like it had corroded in two. I had to dig out the crystal and holder (it was REALLY potted with grey RTV.) Once I got it all back together, I had to tweak a 'factory-set' small pf capacitor in the VCO/varactor circuit; and then it locked after about 5 minutes. Since it is now my only 'standard' I guess I will proclaim myself a true TIME-NUT and start seeking an even better standard. I have three Rockwell GPS-D200 modules ...maybe tying all three together someway will help me vet the rubidium. Btw ...Is there any place in Austin, TX I could walk in with the Efratom and get a 'cesium' check on the Efratom and calibrate it even further??? Appears it has a trimmer for such. -Don Austin, TX ... -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Ed Palmer Sent: Wednesday, December 21, 2011 12:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Efratom FRK - no 10Mhz oscillator Hi Don, I'm assuming that you've checked for obvious things like bad solder joints. After 20 or more years in that heat, anything is possible. Luckily, the oscillator board doesn't have too many connections to remove when you pull the board. I use a 20X magnifier to really get close. I've often found problems that you can't see with less magnification. In one message you mentioned that touching the crystal oven with an external 10 MHz signal starts the oscillator. Isn't the oven supposed to be grounded? I agree with other posters that if you have a bad crystal, you'll have to find a replacement that's made to be used in an oven. However, any old 10 MHz crystal will be useful to diagnose the problem. It might be possible to sacrifice another OCXO and transplant the crystal into the FRK. Your best bet would be an OCXO with an AT crystal. I wouldn't try using an SC crystal. The circuitry would be significantly different. The oven would have to be retuned to match the new crystal, but that's just a resistor change. If you're up for a bigger challenge, you could try interfacing an external OCXO to the Rubidium loop. Rubidiums are typically marketed for low drift applications rather than low Allan Deviation or phase noise. I've wondered whether a high quality SC-crystal OCXO would make a significant improvement in a Rubidium's short-term performance. I've never had a Rubidium with a dead oscillator to experiment on. Ed On 12/21/2011 8:04 AM, Don Lewis wrote: Thanks, Pete. Good tips. I ordered 10 crystals this morning, ...they are dirt cheap. Will try and test one as you suggested. If it is the 'crystal', a bad crystal, ...what then? Do I try to place one of these cheap ones in the oven, ...or do I try to just run it outside the oven or find a high-temperature crystal??? The crystal oven/controller seems fine, ...hot enough to hurt my fingers. Thanks, ...-Don -- -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Bell Sent: Wednesday, December 21, 2011 5:28 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Efratom FRK - no 10Mhz oscillator Yeah, that was why I suggested just sticking a random 10MHz xtal across the pins on the board (with the existing xtal wiring disconnected) - if the rest of the circuit is good, then the oscillator should start up with no problems - if it doesn't, then suspect a fault somewhere else. I just pulled out the manual, and I would start by lifting the connection on E7, and connecting a 10MHz xtal in series with a 10pF cap between the E7 pin and ground. This will bypass both the xtal and the frequency adjustment circuit. If that doesn't work, then the oscillator circuit is the problem - if it does work, then remove the 10 pF cap and connect the xtal directly between E7 and E8 - if it still works, it's almost certainly a bad xtal. If it worked with the 10 pF cap but not with the E8 connection, then check the control voltage (E9: 0.5V-17V) - if that looks good, then suspect the frequency control circuit. If it's bad, then try hooking it to +5V to verify the oscillator and then troubleshoot the servo board. Regards, Pete On Wed, Dec 21, 2011 at 5:00 AM, Azelio Boriani azelio.bori...@screen.it wrote: 10MHz crystals used in OCXO are designed for the temperature of the oven so it is not possible to find an off-the-shelf suitable crystal. Better find a crystal coming from an OCXO. On Tue, Dec 20, 2011 at 7:10 PM, Peter Bellbell.pe...@gmail.com
Re: [time-nuts] Efratom FRK - no 10Mhz oscillator
At the old HP Santa Clara office, they had a cesium clock in the lobby. I was told the 10MHz reference for the facility came from that clock. Reality? Who knows. -Original Message- From: Don Lewis dlewis6...@austin.rr.com Sender: time-nuts-boun...@febo.com Date: Wed, 4 Jan 2012 11:35:24 To: 'Discussion of precise time and frequency measurement'time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Efratom FRK - no 10Mhz oscillator Thanks, all, for your recent help on my Efratom. I finally got it operational. The crystal-holder in the [hot] OCXO was bad; one pin looked like it had corroded in two. I had to dig out the crystal and holder (it was REALLY potted with grey RTV.) Once I got it all back together, I had to tweak a 'factory-set' small pf capacitor in the VCO/varactor circuit; and then it locked after about 5 minutes. Since it is now my only 'standard' I guess I will proclaim myself a true TIME-NUT and start seeking an even better standard. I have three Rockwell GPS-D200 modules ...maybe tying all three together someway will help me vet the rubidium. Btw ...Is there any place in Austin, TX I could walk in with the Efratom and get a 'cesium' check on the Efratom and calibrate it even further??? Appears it has a trimmer for such. -Don Austin, TX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Ed Palmer Sent: Wednesday, December 21, 2011 12:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Efratom FRK - no 10Mhz oscillator Hi Don, I'm assuming that you've checked for obvious things like bad solder joints. After 20 or more years in that heat, anything is possible. Luckily, the oscillator board doesn't have too many connections to remove when you pull the board. I use a 20X magnifier to really get close. I've often found problems that you can't see with less magnification. In one message you mentioned that touching the crystal oven with an external 10 MHz signal starts the oscillator. Isn't the oven supposed to be grounded? I agree with other posters that if you have a bad crystal, you'll have to find a replacement that's made to be used in an oven. However, any old 10 MHz crystal will be useful to diagnose the problem. It might be possible to sacrifice another OCXO and transplant the crystal into the FRK. Your best bet would be an OCXO with an AT crystal. I wouldn't try using an SC crystal. The circuitry would be significantly different. The oven would have to be retuned to match the new crystal, but that's just a resistor change. If you're up for a bigger challenge, you could try interfacing an external OCXO to the Rubidium loop. Rubidiums are typically marketed for low drift applications rather than low Allan Deviation or phase noise. I've wondered whether a high quality SC-crystal OCXO would make a significant improvement in a Rubidium's short-term performance. I've never had a Rubidium with a dead oscillator to experiment on. Ed On 12/21/2011 8:04 AM, Don Lewis wrote: Thanks, Pete. Good tips. I ordered 10 crystals this morning, ...they are dirt cheap. Will try and test one as you suggested. If it is the 'crystal', a bad crystal, ...what then? Do I try to place one of these cheap ones in the oven, ...or do I try to just run it outside the oven or find a high-temperature crystal??? The crystal oven/controller seems fine, ...hot enough to hurt my fingers. Thanks, ...-Don -- -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Bell Sent: Wednesday, December 21, 2011 5:28 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Efratom FRK - no 10Mhz oscillator Yeah, that was why I suggested just sticking a random 10MHz xtal across the pins on the board (with the existing xtal wiring disconnected) - if the rest of the circuit is good, then the oscillator should start up with no problems - if it doesn't, then suspect a fault somewhere else. I just pulled out the manual, and I would start by lifting the connection on E7, and connecting a 10MHz xtal in series with a 10pF cap between the E7 pin and ground. This will bypass both the xtal and the frequency adjustment circuit. If that doesn't work, then the oscillator circuit is the problem - if it does work, then remove the 10 pF cap and connect the xtal directly between E7 and E8 - if it still works, it's almost certainly a bad xtal. If it worked with the 10 pF cap but not with the E8 connection, then check the control voltage (E9: 0.5V-17V) - if that looks
Re: [time-nuts] crunching numbers from XOR phase detector
Have you tried the 74HCT9046? They claim no dead zone. Note - seems to be HCT only. Orin. On Wed, Jan 4, 2012 at 9:32 AM, Brian Justin wa1...@att.net wrote: Be very careful of the FPD in the 4046. It has a dead-zone when the phase error is at or very close to zero. Some versions of the chip claim to have improved that dead-zone. But it's still there to some degree, at least in all the versions I have tried. -Brian, WA1ZMS ___ time-nuts mailing 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] OffsetGenerator
Attila Kinali wrote: Moin Ulrich, On Sun, 25 Dec 2011 13:11:24 +0100 Ulrich Bangertdf...@ulrich-bangert.de wrote: a) A clock shaper as designed by Bruce Griffiths based on a ADCMP600 that should work well to over 100 MHz. I had a short look at the schmeatics and something caught my eyes: On sheet 3 Input Buffers D10/C25 doesn't make sense to me. It looks like an input clamp, but it isn't. What is the purpose of this circuit? Attila Kinali In the usual version of this circuit C11 would be replaced by a short. That version works well - try simulating or building it. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] crunching numbers from XOR phase detector
Not yet, but I guess I will now! Thanks! -Brian - Original Message From: Orin Eman orin.e...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wed, January 4, 2012 12:59:12 PM Subject: Re: [time-nuts] crunching numbers from XOR phase detector Have you tried the 74HCT9046? They claim no dead zone. Note - seems to be HCT only. Orin. On Wed, Jan 4, 2012 at 9:32 AM, Brian Justin wa1...@att.net wrote: Be very careful of the FPD in the 4046. It has a dead-zone when the phase error is at or very close to zero. Some versions of the chip claim to have improved that dead-zone. But it's still there to some degree, at least in all the versions I have tried. -Brian, WA1ZMS ___ time-nuts mailing 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] Efratom FRK - no 10Mhz oscillator
If you have GPSDOs than no need to walk (if not for your health). As already told here, GPSDOs are the best reference we can have and, in the long run, even better than Cs. Use your GPSDOs as a reference and go for a walk without the Rb: clocks must stay quiet. On Wed, Jan 4, 2012 at 6:41 PM, li...@lazygranch.com wrote: At the old HP Santa Clara office, they had a cesium clock in the lobby. I was told the 10MHz reference for the facility came from that clock. Reality? Who knows. -Original Message- From: Don Lewis dlewis6...@austin.rr.com Sender: time-nuts-boun...@febo.com Date: Wed, 4 Jan 2012 11:35:24 To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Efratom FRK - no 10Mhz oscillator Thanks, all, for your recent help on my Efratom. I finally got it operational. The crystal-holder in the [hot] OCXO was bad; one pin looked like it had corroded in two. I had to dig out the crystal and holder (it was REALLY potted with grey RTV.) Once I got it all back together, I had to tweak a 'factory-set' small pf capacitor in the VCO/varactor circuit; and then it locked after about 5 minutes. Since it is now my only 'standard' I guess I will proclaim myself a true TIME-NUT and start seeking an even better standard. I have three Rockwell GPS-D200 modules ...maybe tying all three together someway will help me vet the rubidium. Btw ...Is there any place in Austin, TX I could walk in with the Efratom and get a 'cesium' check on the Efratom and calibrate it even further??? Appears it has a trimmer for such. -Don Austin, TX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Ed Palmer Sent: Wednesday, December 21, 2011 12:12 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Efratom FRK - no 10Mhz oscillator Hi Don, I'm assuming that you've checked for obvious things like bad solder joints. After 20 or more years in that heat, anything is possible. Luckily, the oscillator board doesn't have too many connections to remove when you pull the board. I use a 20X magnifier to really get close. I've often found problems that you can't see with less magnification. In one message you mentioned that touching the crystal oven with an external 10 MHz signal starts the oscillator. Isn't the oven supposed to be grounded? I agree with other posters that if you have a bad crystal, you'll have to find a replacement that's made to be used in an oven. However, any old 10 MHz crystal will be useful to diagnose the problem. It might be possible to sacrifice another OCXO and transplant the crystal into the FRK. Your best bet would be an OCXO with an AT crystal. I wouldn't try using an SC crystal. The circuitry would be significantly different. The oven would have to be retuned to match the new crystal, but that's just a resistor change. If you're up for a bigger challenge, you could try interfacing an external OCXO to the Rubidium loop. Rubidiums are typically marketed for low drift applications rather than low Allan Deviation or phase noise. I've wondered whether a high quality SC-crystal OCXO would make a significant improvement in a Rubidium's short-term performance. I've never had a Rubidium with a dead oscillator to experiment on. Ed On 12/21/2011 8:04 AM, Don Lewis wrote: Thanks, Pete. Good tips. I ordered 10 crystals this morning, ...they are dirt cheap. Will try and test one as you suggested. If it is the 'crystal', a bad crystal, ...what then? Do I try to place one of these cheap ones in the oven, ...or do I try to just run it outside the oven or find a high-temperature crystal??? The crystal oven/controller seems fine, ...hot enough to hurt my fingers. Thanks, ...-Don -- -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Bell Sent: Wednesday, December 21, 2011 5:28 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Efratom FRK - no 10Mhz oscillator Yeah, that was why I suggested just sticking a random 10MHz xtal across the pins on the board (with the existing xtal wiring disconnected) - if the rest of the circuit is good, then the oscillator should start up with no problems - if it doesn't, then suspect a fault somewhere else. I just pulled out the manual, and I would start by lifting the connection on E7, and connecting a 10MHz xtal in series with a 10pF cap between the E7 pin and ground. This will bypass both the xtal and the frequency adjustment
Re: [time-nuts] Navsync CW-12 GPS Board - I don't believe it!!
On 1/4/2012 11:13 AM, Said Jackson wrote: Hi Ed, Since the oscillator is typically free-running in an NCO, and periodically corrected by phase drops to stay on frequency the error you are seeing may be caused be the offset in your crystal, combined with the limited digital resolution of the NCO trying to correct for this offset. If this is the case, your measured error would change with temperature. Does it do that? Yes, it does. Cooling the unit by using a heatsink causes a significant increase in the output frequency. The change is large enough to be obvious on an oscilloscope where one channel is the 10 MHz from the Z3801A and the other channel is the 10 MHz from the CW12. If yes, the NCO resolution is not fractionally corrected all the way. Replacing the on board Tcxo with an ocxo hand-tuned to the correct frequency would help, but that sort of defeats the purpose of the product.. Yes, it appears that the CW12 is just not appropriate for what I was thinking of doing. However, to be fair, the 1 PPS output is much better than the older receivers. I'll have to think about where I go from here. 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] Navsync CW-12 GPS Board - I don't believe it!!
Interesting... this explains why they use a 20MHz OCXO (without EFC) in the FTS125 to clock the receiver that has an NCO steered that clocks a PLL that synchronize another OCXO (with EFC). Yes, I have opened up an FTS125. On Wed, Jan 4, 2012 at 8:32 PM, Ed Palmer ed_pal...@sasktel.net wrote: On 1/4/2012 11:13 AM, Said Jackson wrote: Hi Ed, Since the oscillator is typically free-running in an NCO, and periodically corrected by phase drops to stay on frequency the error you are seeing may be caused be the offset in your crystal, combined with the limited digital resolution of the NCO trying to correct for this offset. If this is the case, your measured error would change with temperature. Does it do that? Yes, it does. Cooling the unit by using a heatsink causes a significant increase in the output frequency. The change is large enough to be obvious on an oscilloscope where one channel is the 10 MHz from the Z3801A and the other channel is the 10 MHz from the CW12. If yes, the NCO resolution is not fractionally corrected all the way. Replacing the on board Tcxo with an ocxo hand-tuned to the correct frequency would help, but that sort of defeats the purpose of the product.. Yes, it appears that the CW12 is just not appropriate for what I was thinking of doing. However, to be fair, the 1 PPS output is much better than the older receivers. I'll have to think about where I go from here. 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] phase lock
I have a Racal-Dana 1992 Nanosecond Universal Counter that includes a phase measuring function. I also have a GPIB interface and wrote some C code to log these readings which can be displayed with gnuplot. The phase should be measured for a very long time - days perhaps. The ability to record the phase over that period is useful because the Thunderbolt will have considerable (compared to the Rb) short term variance. You could use a scope. If the X and Y channels can hack 10 MHz you can do a Lissajous pattern. Otherwise display one and trigger on the other. The frequency should be within a fraction of one Hz before worrying about the phase. On 12/23/2011 03:32 PM, Mark C. Stephens wrote: Hello Chuck, I noticed with interest you compared a thunderbolt to a RB standard using phase lock. I wonder how you measured the phase lock? My thoughts would be to use an Oscilloscope but do you have another method? Many thanks, Mark *Kind Regards,* Mark Stephens ** *Mark C Stephens* | Customer service engineer | Non-Stop Computer Ltd (+61 2 9011 8186 | (+61 428 256 334 | +ma...@non-stop.com.au mailto:ma...@non-stop.com.au Non-Stop Computer PTY LTD 79 Devon St North Epping NSW 2121 Australia Email: serv...@non-stop.com.au -- Chuck Forsberg WA7KGX n2469r...@omen.comwww.omen.com Developer of Industrial ZMODEM(Tm) for Embedded Applications Omen Technology Inc The High Reliability Software 10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430 ___ time-nuts mailing 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] Navsync CW-12 GPS Board - I don't believe it!!
Hello Azelio, we looked at one here ordered from Digikey, and it had two VCXO's/TCXOs. They did not use any OCXO's. Lot's of folks ask us why the CW parts are lower cost than real GPSDO's, I guess now we know.. bye, Said In a message dated 1/4/2012 12:33:34 Pacific Standard Time, azelio.bori...@screen.it writes: Interesting... this explains why they use a 20MHz OCXO (without EFC) in the FTS125 to clock the receiver that has an NCO steered that clocks a PLL that synchronize another OCXO (with EFC). Yes, I have opened up an FTS125. On Wed, Jan 4, 2012 at 8:32 PM, Ed Palmer ed_pal...@sasktel.net wrote: On 1/4/2012 11:13 AM, Said Jackson wrote: ___ time-nuts mailing 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] Navsync CW-12 GPS Board - I don't believe it!!
Hi Ed, sorry to hear that, contact me off-list and I will try to solve your problem. I tried sending you an email, but my mails must be getting filtered by your spam filter.. bye, Said In a message dated 1/4/2012 11:33:14 Pacific Standard Time, ed_pal...@sasktel.net writes: On 1/4/2012 11:13 AM, Said Jackson wrote: Hi Ed, Since the oscillator is typically free-running in an NCO, and periodically corrected by phase drops to stay on frequency the error you are seeing may be caused be the offset in your crystal, combined with the limited digital resolution of the NCO trying to correct for this offset. If this is the case, your measured error would change with temperature. Does it do that? Yes, it does. Cooling the unit by using a heatsink causes a significant increase in the output frequency. The change is large enough to be obvious on an oscilloscope where one channel is the 10 MHz from the Z3801A and the other channel is the 10 MHz from the CW12. If yes, the NCO resolution is not fractionally corrected all the way. Replacing the on board Tcxo with an ocxo hand-tuned to the correct frequency would help, but that sort of defeats the purpose of the product.. Yes, it appears that the CW12 is just not appropriate for what I was thinking of doing. However, to be fair, the 1 PPS output is much better than the older receivers. I'll have to think about where I go from here. 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] FE-5680A performance
On 1/4/2012 3:18 PM, saidj...@aol.com wrote: Here is a set of performance plots for the FE5680A that we had measured before. Performance has improved significantly, ADEV is now in the xE-012's. Phase noise and spurs are worse than originally reported, they kind of suck. Frequency over time looks quite nice though, definitely quite useful as a frequency reference. bye, Said Said: Your vertical units per division for the frequency plot don't make sense. Please re-check and let us know. Thanks, --- Graham == ___ time-nuts mailing 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] Efratom FRK - no 10Mhz oscillator
Btw ...Is there any place in Austin, TX I could walk in with the Efratom and get a 'cesium' check on the Efratom and calibrate it even further??? Appears it has a trimmer for such. If you move your gear to someplace strange, you have to consider warm up time and changes in temperature and local magnetic field and who knows what else. You can calibrate it without help from a cesium. Just use GPS and wait long enough for the short term noise to be insignificant. One approach would be to use the 10 MHz from your Efratom FRK to drive the clock on one of tvb's picPETs and feed the PPS from your GPS to its event input. http://www.leapsecond.com/pic/picpet.htm Then just collect the data for a day or week. -- These are my opinions, not necessarily my employer's. 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.
[time-nuts] Temporal cloaking in Nature journal
The abstract and a two graphics are online at http://www.nature.com/nature/journal/v481/n7379/full/nature10695.html ___ time-nuts mailing 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] Navsync CW-12 GPS Board - I don't believe it!!
It depends on the option ordered: the FTS125s we have are FTS125-COO (double OCXO) the -CTV option is the TCXO/VCXO option, there is the -COV option too. On Wed, Jan 4, 2012 at 10:08 PM, saidj...@aol.com wrote: Hi Ed, sorry to hear that, contact me off-list and I will try to solve your problem. I tried sending you an email, but my mails must be getting filtered by your spam filter.. bye, Said In a message dated 1/4/2012 11:33:14 Pacific Standard Time, ed_pal...@sasktel.net writes: On 1/4/2012 11:13 AM, Said Jackson wrote: Hi Ed, Since the oscillator is typically free-running in an NCO, and periodically corrected by phase drops to stay on frequency the error you are seeing may be caused be the offset in your crystal, combined with the limited digital resolution of the NCO trying to correct for this offset. If this is the case, your measured error would change with temperature. Does it do that? Yes, it does. Cooling the unit by using a heatsink causes a significant increase in the output frequency. The change is large enough to be obvious on an oscilloscope where one channel is the 10 MHz from the Z3801A and the other channel is the 10 MHz from the CW12. If yes, the NCO resolution is not fractionally corrected all the way. Replacing the on board Tcxo with an ocxo hand-tuned to the correct frequency would help, but that sort of defeats the purpose of the product.. Yes, it appears that the CW12 is just not appropriate for what I was thinking of doing. However, to be fair, the 1 PPS output is much better than the older receivers. I'll have to think about where I go from here. 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] Navsync CW-12 GPS Board - I don't believe it!!
yes, see that now, looks like the OCXO option about doubles the price of the unit on Digikey.. In a message dated 1/4/2012 13:56:59 Pacific Standard Time, azelio.bori...@screen.it writes: It depends on the option ordered: the FTS125s we have are FTS125-COO (double OCXO) the -CTV option is the TCXO/VCXO option, there is the -COV option too. ___ time-nuts mailing 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] FE-5680A dumb question...
Pin 7 is 10 MHz Pin 6 is 1 PPS Jim From: Brian, WA1ZMS wa1...@att.net To: Time-Nuts time-nuts@febo.com Sent: Tuesday, January 3, 2012 5:58 PM Subject: [time-nuts] FE-5680A dumb question... My E-bay FE-5680A finally arrived. (4weeks later) Of the pins on the DB-9 connector, which one is the RF output? The manual only talks about an SMA output. I know this has been talked about before, but I cannot find the thread. Thanks in advance sorry for bandwidth, -Brian, WA1ZMS ___ time-nuts mailing 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] FE-5680A performance
Thanks for posting this. The slight hump in the adev plot at approx 1,300 seconds is interesting (and similar to what I am seeing in another Rb from another vendor.) --- On Wed, 1/4/12, saidj...@aol.com saidj...@aol.com wrote: From: saidj...@aol.com saidj...@aol.com Subject: Re: [time-nuts] FE-5680A performance To: time-nuts@febo.com Received: Wednesday, January 4, 2012, 4:18 PM Here is a set of performance plots for the FE5680A that we had measured before. Performance has improved significantly, ADEV is now in the xE-012's. Phase noise and spurs are worse than originally reported, they kind of suck. Frequency over time looks quite nice though, definitely quite useful as a frequency reference. bye, Said -Inline Attachment Follows- ___ time-nuts mailing 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] FE-5680A performance
Hi Graham, the TSC5125A has auto-scaled the plot to 2E-04Hz fractional frequency from 10MHz, or in other words one vertical division is 2E-011 at 10MHz, or 20 parts per trillion, or 0.0002Hz error. I also don't like the way the TSC shows the frequency, and the fact that you can only capture about 9 minutes of information for some reason. Why not show 24 hours or 48 hours of data here? With this in mind, the FE5680A wanders around about +/-6E-011 max in this plot. Hope that helps, Said In a message dated 1/4/2012 13:41:07 Pacific Standard Time, time...@austin.rr.com writes: On 1/4/2012 3:18 PM, _SAIDJACK@aol.com_ (mailto:saidj...@aol.com) wrote: Here is a set of performance plots for the FE5680A that we had measured before. Performance has improved significantly, ADEV is now in the xE-012's. Phase noise and spurs are worse than originally reported, they kind of suck. Frequency over time looks quite nice though, definitely quite useful as a frequency reference. bye, Said Said: Your vertical units per division for the frequency plot don't make sense. Please re-check and let us know. Thanks, --- Graham ___ time-nuts mailing 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] Navsync CW-12 GPS Board - I don't believe it!!
The OCXO used are marked OFC3DJ1AA (fixed) and OVC3CE1AA (with EFC) but no data I have found: only OVC5 and OFC5 series. On Wed, Jan 4, 2012 at 11:04 PM, saidj...@aol.com wrote: yes, see that now, looks like the OCXO option about doubles the price of the unit on Digikey.. In a message dated 1/4/2012 13:56:59 Pacific Standard Time, azelio.bori...@screen.it writes: It depends on the option ordered: the FTS125s we have are FTS125-COO (double OCXO) the -CTV option is the TCXO/VCXO option, there is the -COV option too. ___ time-nuts mailing 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] FE-5680A performance
Wow, have you a TSC5125A? Lucky you... On Wed, Jan 4, 2012 at 11:12 PM, saidj...@aol.com wrote: Hi Graham, the TSC5125A has auto-scaled the plot to 2E-04Hz fractional frequency from 10MHz, or in other words one vertical division is 2E-011 at 10MHz, or 20 parts per trillion, or 0.0002Hz error. I also don't like the way the TSC shows the frequency, and the fact that you can only capture about 9 minutes of information for some reason. Why not show 24 hours or 48 hours of data here? With this in mind, the FE5680A wanders around about +/-6E-011 max in this plot. Hope that helps, Said In a message dated 1/4/2012 13:41:07 Pacific Standard Time, time...@austin.rr.com writes: On 1/4/2012 3:18 PM, _SAIDJACK@aol.com_ (mailto:saidj...@aol.com) wrote: Here is a set of performance plots for the FE5680A that we had measured before. Performance has improved significantly, ADEV is now in the xE-012's. Phase noise and spurs are worse than originally reported, they kind of suck. Frequency over time looks quite nice though, definitely quite useful as a frequency reference. bye, Said Said: Your vertical units per division for the frequency plot don't make sense. Please re-check and let us know. Thanks, --- Graham ___ time-nuts mailing 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] FE-5680A performance
Yes, it is the most amazing time nut tool! The older TSC5115A is also amazing. I consider myself very lucky... bye, Said In a message dated 1/4/2012 14:17:48 Pacific Standard Time, azelio.bori...@screen.it writes: Wow, have you a TSC5125A? Lucky you... On Wed, Jan 4, 2012 at 11:12 PM, saidj...@aol.com wrote: Hi Graham, the TSC5125A has auto-scaled the plot to 2E-04Hz fractional frequency from 10MHz, or in other words one vertical division is 2E-011 at 10MHz, or 20 parts per trillion, or 0.0002Hz error. I also don't like the way the TSC shows the frequency, and the fact that you can only capture about 9 minutes of information for some reason. Why not show 24 hours or 48 hours of data here? With this in mind, the FE5680A wanders around about +/-6E-011 max in this plot. Hope that helps, Said In a message dated 1/4/2012 13:41:07 Pacific Standard Time, time...@austin.rr.com writes: On 1/4/2012 3:18 PM, _SAIDJACK@aol.com_ (mailto:saidj...@aol.com) wrote: Here is a set of performance plots for the FE5680A that we had measured before. Performance has improved significantly, ADEV is now in the xE-012's. Phase noise and spurs are worse than originally reported, they kind of suck. Frequency over time looks quite nice though, definitely quite useful as a frequency reference. bye, Said Said: Your vertical units per division for the frequency plot don't make sense. Please re-check and let us know. Thanks, --- Graham ___ time-nuts mailing 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] crunching numbers from XOR phase detector
On 1/4/12 8:14 AM, Joe Gwinn wrote: At 10:16 AM + 1/4/12, time-nuts-requ...@febo.com wrote: Date: Wed, 04 Jan 2012 00:58:24 -0800 From: Hal Murray hmur...@megapathdsl.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] crunching numbers from XOR phase detector Message-ID: 20120104085824.8426e800...@ip-64-139-1-69.sjc.megapath.net Content-Type: text/plain; charset=us-ascii Neat. Thanks for sharing. With a XOR, you can't tell which input is higher frequency. I think you can fix that with a second XOR and a delay line. I think 90 degrees of delay will provide the most information. At 10 MHz, that's 25 ns. I think that's about 15 feet of good coax. Beware of teflon dielectric cable, as the teflon knee is centered around room temperature, making delay cables of teflon quite sensitive to slight changes in temperature. http://www.micro-coax.com/pages/technicalinfo/applications/27.asp See also http://www.gore.com/en_xx/products/cables/microwave/phase-stability-whitepaper.html http://www.gore.com/en_xx/products/cables/microwave/changes-insertion-loss-phase.html Yeah, but the change is pretty small, (a few hundred ppm) and overall, those cables have fairly low temperature coefficient. The latter Gore writeup shows 0.2 deg/GHz/ft across the knee For the 10 MHz scenario at 15ft, that's .03 degrees, 83 ppm You sort of have a choice between a cable that has low overall variation, but a step in the curve OR a cable that has a smooth characteristic and no bumps. Interestingly, other dielectrics don't show this effect. In particular, the silica dielectric stuff is very stable. ___ time-nuts mailing 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] crunching numbers from XOR phase detector
The XOR phase comparator is without feed-back and that simply means no dead-zone. This is consistent with literature on XOR PDs. It will of course have non-linearity which is improving with speed of the process technology. A 74HC4046 will be better than a CD4046. BUT the low-frequency noise is inversely proportional to channel-length of the used MOSFETs. So for time-nuts interests a slower CD4046 can be better. The other 4046 phase comparators are made of flip-flops where the dead-zone is proportional to gate-delay. For ultimate performance one have to use a classical DRM. - Henry Brian Justin schrieb: Not yet, but I guess I will now! Thanks! -Brian - Original Message From: Orin Eman orin.e...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wed, January 4, 2012 12:59:12 PM Subject: Re: [time-nuts] crunching numbers from XOR phase detector Have you tried the 74HCT9046? They claim no dead zone. Note - seems to be HCT only. Orin. On Wed, Jan 4, 2012 at 9:32 AM, Brian Justin wa1...@att.net wrote: Be very careful of the FPD in the 4046. It has a dead-zone when the phase error is at or very close to zero. Some versions of the chip claim to have improved that dead-zone. But it's still there to some degree, at least in all the versions I have tried. -Brian, WA1ZMS -- ehydra.dyndns.info ___ time-nuts mailing 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] FE-5680A performance
Hi Said, Excellent plots - what program/ how are you producing the plots? 73, Bill, WA2DVU Cape May, NJ -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of saidj...@aol.com Sent: Wednesday, January 04, 2012 4:18 PM To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A performance Here is a set of performance plots for the FE5680A that we had measured before. Performance has improved significantly, ADEV is now in the xE-012's. Phase noise and spurs are worse than originally reported, they kind of suck. Frequency over time looks quite nice though, definitely quite useful as a frequency reference. bye, Said ___ time-nuts mailing 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] FE-5680A performance
Said: Thanks fro the explanation. I didn't understand the scaling method. --- Graham == On 1/4/2012 4:12 PM, saidj...@aol.com wrote: Hi Graham, the TSC5125A has auto-scaled the plot to 2E-04Hz fractional frequency from 10MHz, or in other words one vertical division is 2E-011 at 10MHz, or 20 parts per trillion, or 0.0002Hz error. I also don't like the way the TSC shows the frequency, and the fact that you can only capture about 9 minutes of information for some reason. Why not show 24 hours or 48 hours of data here? With this in mind, the FE5680A wanders around about +/-6E-011 max in this plot. Hope that helps, Said In a message dated 1/4/2012 13:41:07 Pacific Standard Time, time...@austin.rr.com writes: On 1/4/2012 3:18 PM, saidj...@aol.com wrote: Here is a set of performance plots for the FE5680A that we had measured before. Performance has improved significantly, ADEV is now in the xE-012's. Phase noise and spurs are worse than originally reported, they kind of suck. Frequency over time looks quite nice though, definitely quite useful as a frequency reference. bye, Said Said: Your vertical units per division for the frequency plot don't make sense. Please re-check and let us know. Thanks, --- Graham ___ time-nuts mailing 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] FE-5680A performance
Hello Bill, They are printed to a postscript file by the TSC5125A using the print button on the tsc. After FTP download I use Acrobat Professional to convert the PS file to PDF. Results in good quality plots with small file size. Bye, Said Sent from my iPad On Jan 4, 2012, at 15:25, Bill Riches bill.ric...@verizon.net wrote: Hi Said, Excellent plots - what program/ how are you producing the plots? 73, Bill, WA2DVU Cape May, NJ -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of saidj...@aol.com Sent: Wednesday, January 04, 2012 4:18 PM To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A performance Here is a set of performance plots for the FE5680A that we had measured before. Performance has improved significantly, ADEV is now in the xE-012's. Phase noise and spurs are worse than originally reported, they kind of suck. Frequency over time looks quite nice though, definitely quite useful as a frequency reference. bye, Said ___ time-nuts mailing 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] FE-5680A dumb question...
Thank you though. Got it working fine thanks to all the answers and help! -Brian, WA1ZMS -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of gonzo . Sent: Wednesday, January 04, 2012 2:18 AM To: time-nuts Subject: Re: [time-nuts] FE-5680A dumb question... Hi Brian. Taking the list concensus and confirming it on my recently arrived '5680A, the pinout is as follows: 1. +15V (1500mA cold: 800mA hot) 2. Gnd 3. Rb Lock (lock = low) 4. +5V (~85mA) 5. Gnd 6. 1PPS (high until Rb Lock goes low) 7. 10Mhz 8. RS323-RX 9. RS232-TX These pinouts are not consistant across the FE-5680A range, but seems good for the 'current batch' of cheap units coming out of china. Cheers, ian Date: Tue, 3 Jan 2012 20:58:10 -0500 From: Brian, WA1ZMS wa1...@att.net To: Time-Nuts time-nuts@febo.com Subject: [time-nuts] FE-5680A dumb question... Message-ID: 01ccca84$4ff2d570$efd88050$@att.net Content-Type: text/plain; charset=us-ascii My E-bay FE-5680A finally arrived. (4weeks later) Of the pins on the DB-9 connector, which one is the RF output? The manual only talks about an SMA output. I know this has been talked about before, but I cannot find the thread. Thanks in advance sorry for bandwidth, -Brian, WA1ZMS ___ time-nuts mailing 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] FE-5680A dumb question...
Chris, I you look carefully there should be 1PPS on pin 6, about 1 us wide. You need to adjust your scope trigger and advance the brightness because of this extremely low duty cycle. Maybe you'll not see the signal but your scope will trigger at 1 PPS. Or you can connect a counter and see 1 Hz. Regards, Ignacio, EB4APL On 04/01/2012 7:40, Chris Albertson wrote: The manual is for a similar unit with the same part number. On this unit (I was going to be sarcastic and say Its the pin with the 10MHz sine wave on it but here it the pinout. I get about 2V peak to peak when loaded with a 10X scope probe only 1 +15V 2 return for #1 3 lock.unlock 4 +5V 5 gnd 6 N/C (but I see a tiny ~60MHz sine-like wave 7 10MHZ output 8 rs232 Rx 9 rs232 Tx On Tue, Jan 3, 2012 at 5:58 PM, Brian, WA1ZMSwa1...@att.net wrote: My E-bay FE-5680A finally arrived. (4weeks later) Of the pins on the DB-9 connector, which one is the RF output? The manual only talks about an SMA output. I know this has been talked about before, but I cannot find the thread. Thanks in advance sorry for bandwidth, -Brian, WA1ZMS ___ time-nuts mailing 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] FE-5680A performance
On 1/4/2012 7:44 PM, Said Jackson wrote: They are printed to a postscript file by the TSC5125A using the print button on the tsc. How long until they're $200 on eBay? :-) ___ time-nuts mailing 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] FE-5680A performance
Mike, Buy $500 worth of silver coins or bars today. Should get you about 15 ounces. Within 3 to 5 years you may be able to trade that for a used TSC5115A... Sent from my iPad On Jan 4, 2012, at 17:20, Mike S mi...@flatsurface.com wrote: On 1/4/2012 7:44 PM, Said Jackson wrote: They are printed to a postscript file by the TSC5125A using the print button on the tsc. How long until they're $200 on eBay? :-) ___ time-nuts mailing 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] FE-5680A performance
Ah ha!! I was hoping that it was a simple excel procedure!! Nice piece of gear. Regards Bill -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Said Jackson Sent: Wednesday, January 04, 2012 7:45 PM To: Discussion of precise time and frequency measurement Cc: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] FE-5680A performance Hello Bill, They are printed to a postscript file by the TSC5125A using the print button on the tsc. After FTP download I use Acrobat Professional to convert the PS file to PDF. Results in good quality plots with small file size. Bye, Said Sent from my iPad On Jan 4, 2012, at 15:25, Bill Riches bill.ric...@verizon.net wrote: Hi Said, Excellent plots - what program/ how are you producing the plots? 73, Bill, WA2DVU Cape May, NJ -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of saidj...@aol.com Sent: Wednesday, January 04, 2012 4:18 PM To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A performance Here is a set of performance plots for the FE5680A that we had measured before. Performance has improved significantly, ADEV is now in the xE-012's. Phase noise and spurs are worse than originally reported, they kind of suck. Frequency over time looks quite nice though, definitely quite useful as a frequency reference. bye, Said ___ time-nuts mailing 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] FE-5680A performance
Hi Graham, the TSC5125A has auto-scaled the plot to 2E-04Hz fractional frequency from 10MHz, or in other words one vertical division is 2E-011 at 10MHz, or 20 parts per trillion, or 0.0002Hz error. I also don't like the way the TSC shows the frequency, and the fact that you can only capture about 9 minutes of information for some reason. Why not show 24 hours or 48 hours of data here? Grab the latest release from www.miles.io/timelab/readme.htm if you like -- it will acquire from the TSC 5125A for as many hours/days as the TSC's Ethernet connection will stay up. (Which sometimes isn't very long.) TimeLab generates its frequency-difference plot from the acquired phase data, so it will give you various display and filtering options that the 5125A itself will not. -- john Miles Design LLC ___ time-nuts mailing 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] FE-5680A performance
I also don't like the way the TSC shows the frequency, and the fact that you can only capture about 9 minutes of information for some reason. Why not show 24 hours or 48 hours of data here? Said, The 9+ minutes (540+ seconds) is due to the 640 pixel display minus the soft menu that appears on the right side. The TSC doesn't save all the raw data from the run and thus you can't pan or zoom over the data like you would expect. Note there is no harddrive in the TSC (the CF card is just a boot filesystem). So there are two tricks you can use. The first is what I do, which is to capture all the raw phase data from the TSC, logging it on PC, and then use Stable32 or TimeLab to manipulate or plot as much or as little of the data as desired. Many of the plots on my web site are created this way. I almost always begin a log of raw data before I press start on a TSC analyzer. That way I have a permanent copy of all the phase data, from which all other analysis is based. Depending on the model of TSC, the raw phase data is delivered by RS-232 or LAN at rates of 1 Hz, 100 Hz, or 1 kHz. For really long runs (days or weeks, even months) I typically use 1 Hz. The second solution, one I would strongly recommend, is to use the live capture capability in TimeLab. John has built-in support for a number of popular counters, including the TSC. I'm pretty sure you can get it going in a matter of minutes; you will never look back. /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] FE-5680A performance
I found the undocumented PPS signal on pin 6. This is on the new $38 unit I just got. Question: Can anyone measure the pulse? How wide is it and what is the voltage? Here is my setup: Have an older Tek 465 scope that is in only fair shape and I see nothing on that pin but milivolt level sine wave of about 60MHz. I can't set the scope to show any hint of a PPS but I know it's there because I routed the scope's vertical amplifier output to channel A of an HP5328 counter, measured period A and I get 97.5 uSec period. So I'm sure the PPS is going through the scope. But I can't see it so I can't measure it. Next I place the PPS from an Oncore UT+ GPS on Channel A and I get very close to the same period. I suspect my counter needs calibration. Next experiment: Route the FE-5680's 10MHz output to the counter's external clock input. Now the counter is running off the Rb. Then I measure the GPS' PPS and the period is exactly 1 second except for the last digit which some times flips to 1 or 9 (the expected one count random error) So I think the Rb is better than whatever oscillator is inside the HP counter. Next experiments are a long term comparison of the GPS and Rb PPS but I need to know the height and width of the FE5680's PPS. I 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.
