Re: [time-nuts] Termination talk
Gee, one would have thought he would have been proud of us I tell everyone I'm a 'Time-Nut.' They agree. =Don - -Original Message- From: Ulrich Bangert Sent: Thursday, November 29, 2012 1:28 AM To: 'M. Simon' ; 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Termination talk Simon, ...which prefers to remain anonymous... sounds as if it were a group of criminals or so. Best regards Ulrich Bangert -Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von M. Simon Gesendet: Mittwoch, 28. November 2012 23:53 An: time-nuts@febo.com Betreff: [time-nuts] Termination talk I was going to post an anecdote about termination to the list and then thought that the piece would make a great column. It did. My magazine featured it in one of its daily mailings. If you want to check it out: http://www.ecnmag.com/blogs/2012/11/long-lines-pcb Simon Engineering is the art of making what you want from what you can get at a profit. ___ time-nuts mailing 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.wlEmoticon-clock[1].png___ time-nuts mailing 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] EIP545A 18GHz counter query
Chris, Put a ohmmeter across any of the capacitors on the GPIB board and see what the resistance is. Since that kills the unit, I suspect the resistance is low (?shorted tantalum) or there is a problem with one of the chips that takes the 5 VDC buss down. Make sure of the polarity of your DMM, + to + and - to ground. Alternatively, there is a short on the +5 VDC line at the connector on the mother board that is 'actuated' by plugging the board in. Measure the resistance to ground of the +5 VDC buss (power off) with the GPIB board plugged in and not plugged in. Joe Thanks again Joe, checked the tants on the GPIB board and they seem fine, have put this aside until the rest is AOK. Then I'll pull the chips one by one and try and isolate the issue. The 5 v bus seems good with the board in or out, too. 29/11/2012 09:27 -- Best Regards, Chris Wilson. ___ time-nuts mailing 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] EIP545A 18GHz counter query
29/11/2012 09:30 The replacement for the missing U6 chip arrived this morning and it now completes the 200 MHz self test It will read up to the limit of my frequency generator on Band 3 which is only 1040 MHz, but looks promising. Band 2 also works, but seemingly has an anomaly. I cannot get Band 2 to read below 185.000 MHz. If I input 184.900 it won't read it and displays zeros. 185 and up is OK... Weird. It should read from 10 MHz up to 1 GHz. It'll go to 1 GHz plus AOK. Band 1 appears to work fine. These tests are with both my GPS referenced external standard and the internal reference used. So Band 2 appears to have a further issue. Will refer to the manual and see if I can fathom it out. Any ideas as to why Band 2 will only read from 185 MHz upwards please? Thanks. -- Best Regards, Chris Wilson. ___ time-nuts mailing 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] Frequency generator and counter on same external reference?
29/11/2012 09:40 I don't think this is an issue, but thought it best to ask. I am repairing an 18GHz counter and it has a 10MHz external reference port. So does my elderly Marconi 2019A sig gen. Is there any potential issue having them both referenced off my Thunderbolt GPS referenced standard, at the same time? Thanks. -- Best Regards, Chris Wilson. mailto: ch...@chriswilson.tv ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Termination talk
I was told specifically not to mention the name of the list in my articles by the list owner. The point being to avoid an inundation of people with only casual interest. Simon Engineering is the art of making what you want from what you can get at a profit. From: dlewis6767 dlewis6...@austin.rr.com To: 'M. Simon' msimon6...@yahoo.com; 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Thursday, November 29, 2012 8:17 AM Subject: Re: [time-nuts] Termination talk Gee, one would have thought he would have been proud of us I tell everyone I'm a 'Time-Nut.' They agree. =Don - -Original Message- From: Ulrich Bangert Sent: Thursday, November 29, 2012 1:28 AM To: 'M. Simon' ; 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] Termination talk Simon, ...which prefers to remain anonymous... sounds as if it were a group of criminals or so. Best regards Ulrich Bangert -Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von M. Simon Gesendet: Mittwoch, 28. November 2012 23:53 An: time-nuts@febo.com Betreff: [time-nuts] Termination talk I was going to post an anecdote about termination to the list and then thought that the piece would make a great column. It did. My magazine featured it in one of its daily mailings. If you want to check it out: http://www.ecnmag.com/blogs/2012/11/long-lines-pcb Simon Engineering is the art of making what you want from what you can get at a profit. ___ time-nuts mailing 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] Termination talk
sounds as if it were a group of criminals or so. Time bandits. Simon Engineering is the art of making what you want from what you can get at a profit. From: Ulrich Bangert df...@ulrich-bangert.de To: 'M. Simon' msimon6...@yahoo.com; 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Thursday, November 29, 2012 7:28 AM Subject: AW: [time-nuts] Termination talk Simon, ...which prefers to remain anonymous... sounds as if it were a group of criminals or so. Best regards Ulrich Bangert -Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von M. Simon Gesendet: Mittwoch, 28. November 2012 23:53 An: time-nuts@febo.com Betreff: [time-nuts] Termination talk I was going to post an anecdote about termination to the list and then thought that the piece would make a great column. It did. My magazine featured it in one of its daily mailings. If you want to check it out: http://www.ecnmag.com/blogs/2012/11/long-lines-pcb Simon Engineering is the art of making what you want from what you can get at a profit. ___ time-nuts mailing 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] Best phase detector / mixer for 100MHz?
Hi Would be nice to use something like the ADS1278. http://www.ti.com/product/ads1278 Lots of channels to cross correlate, and very little flicker noise. Bob On Nov 28, 2012, at 9:29 AM, Support HpW-Works.com supp...@hpw-works.com wrote: Hi Bruce, The equivalent phase noise (measured in dBc/Hz) is essentially independent of the sample size. The dBc/Hz normalization is based on this (also the sample rate). While the sample rate sample size = FFT Bin size (resolution or filter band width) is used to get the required correction factor of the spectrum to get the dBc / (1Hz) Y scaling back. So increasing the sample size isnt particularly useful for reducing the phase noise floor. By theory, yes... but we use a sound card with a lot of flicker noise on the lower end, also we have the 10...20Hz low freq. cutoff due the usage of a servo / single 5V power. Also the raising noise below 100Hz (ADC serve noise on the ADC power / input circuit) limits the performance. In my simple test increase of the sample size reduced the noise floor in better way than just using sample size with 1-2K and large averaging cycles. Keep in mind, Bin resolution is sample rate / sample size: Example: - 32khz / 32678 = about 1Hz - 32khz / 1024 = about 31 Hz However with a sound card plus a mixer a somewhat lower number of samples should suffice since there is no carrier. Ideally the input circuit ADC of the 3562A would be nice but with much larger RAM buffer and ASIO interface O:) Hanspeter -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bruce Griffiths Sent: Dienstag, 27. November 2012 12:31 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Best phase detector / mixer for 100MHz? Support HpW-Works.com wrote: Bruce, There's no evidence of a cross power spectrum function in this suite. One needs to be able to average at least 10,000 cross power spectra for some applications. In the PSD (power density) PSP (power spectrum) there are cross power and cross power complex average implemented (selectable using the spectrum channel mixer)! Additional to this you may apply / add averaging of the resulting spectrum or use additional peak hold. Average of 10'000 cross points is a large count and often seen on 1-4k sample size. Better in my opinion is to use a higher sample size 32k-64k and then less averaging is required. The equivalent phase noise (measured in dBc/Hz) is essentially independent of the sample size. So increasing the sample size isnt particularly useful for reducing the phase noise floor. The increased frequency resolution achieved by increasing the sample size is only useful for measuring spurs. In the direct digital method of measuring phase noise a few terasamples (a few gigasamples at baseband) need to be processed to achieve a sufficiently low instrument noise floor. However with a sound card plus a mixer a somewhat lower number of samples should suffice since there is no carrier. Just download the evaluation version with fully feature set. HpW 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. ___ time-nuts mailing 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] EIP545A 18GHz counter query
I had the same problem with my 545A, and it turned out to be a tin whisker thing. Scrub both the GPIB card, and the main controller card with a brush, and then blow them off with compressed air. Try to get the air close to each chip and socket, and blow from all angles. Plug the cards back in, and I think you will be in for a pleasant surprise. -Chuck Harris Chris Wilson wrote: Chris, Put a ohmmeter across any of the capacitors on the GPIB board and see what the resistance is. Since that kills the unit, I suspect the resistance is low (?shorted tantalum) or there is a problem with one of the chips that takes the 5 VDC buss down. Make sure of the polarity of your DMM, + to + and - to ground. Alternatively, there is a short on the +5 VDC line at the connector on the mother board that is 'actuated' by plugging the board in. Measure the resistance to ground of the +5 VDC buss (power off) with the GPIB board plugged in and not plugged in. Joe Thanks again Joe, checked the tants on the GPIB board and they seem fine, have put this aside until the rest is AOK. Then I'll pull the chips one by one and try and isolate the issue. The 5 v bus seems good with the board in or out, too. 29/11/2012 09:27 ___ time-nuts mailing 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] EIP545A 18GHz counter query
It sounds like a SW limit, not hardware. Silly question: Have you read the manual? -John = 29/11/2012 09:30 The replacement for the missing U6 chip arrived this morning and it now completes the 200 MHz self test It will read up to the limit of my frequency generator on Band 3 which is only 1040 MHz, but looks promising. Band 2 also works, but seemingly has an anomaly. I cannot get Band 2 to read below 185.000 MHz. If I input 184.900 it won't read it and displays zeros. 185 and up is OK... Weird. It should read from 10 MHz up to 1 GHz. It'll go to 1 GHz plus AOK. Band 1 appears to work fine. These tests are with both my GPS referenced external standard and the internal reference used. So Band 2 appears to have a further issue. Will refer to the manual and see if I can fathom it out. Any ideas as to why Band 2 will only read from 185 MHz upwards please? Thanks. -- Best Regards, Chris Wilson. ___ time-nuts mailing 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] Frequency generator and counter on same external reference
Good heavens, no. By doing so, they both have the same reference and the measuremets actually means something. I have a stack of HP stuff (3586, 3386 and assorted counters) all T'd off my Tbolt without issue. The only caveat is that you don't put too much stuff across the T-bolt output so as to load it down to the point where some device can't get clocking. Before you hit that point, you may need a high quality (low jitter) distribution amp in the timing chain. Date: Thu, 29 Nov 2012 09:42:39 + From: Chris Wilson Subject: [time-nuts] Frequency generator and counter on same external reference? I am repairing an 18GHz counter and it has a 10MHz external reference port. So does my elderly Marconi 2019A sig gen. Is there any potential issue having them both referenced off my Thunderbolt GPS referenced standard, at the same time? ___ time-nuts mailing 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] Termination talk
...yeah - it's better not to know those people ;-) ... Am 29.11.2012 08:28, schrieb Ulrich Bangert: Simon, ...which prefers to remain anonymous... sounds as if it were a group of criminals or so. Best regards Ulrich Bangert -Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von M. Simon Gesendet: Mittwoch, 28. November 2012 23:53 An: time-nuts@febo.com Betreff: [time-nuts] Termination talk I was going to post an anecdote about termination to the list and then thought that the piece would make a great column. It did. My magazine featured it in one of its daily mailings. If you want to check it out: http://www.ecnmag.com/blogs/2012/11/long-lines-pcb Simon Engineering is the art of making what you want from what you can get at a profit. ___ time-nuts mailing 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] EIP545A 18GHz counter query
It sounds like a SW limit, not hardware. Silly question: Have you read the manual? -John 29/11/2012 15:31 Hi John, will re read the section on limits, but please see my reply to Chuck I just posted. Cheers. -- Best Regards, Chris Wilson. ___ time-nuts mailing 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] Frequency generator and counter on same external reference
Good heavens, no. By doing so, they both have the same reference and the measuremets actually means something. I have a stack of HP stuff (3586, 3386 and assorted counters) all T'd off my Tbolt without issue. The only caveat is that you don't put too much stuff across the T-bolt output so as to load it down to the point where some device can't get clocking. Before you hit that point, you may need a high quality (low jitter) distribution amp in the timing chain. 29/11/2012 15:44 I thought it would be fine, but thought and know can be poles apart at my level of knowledge :) Thanks for that. -- Best Regards, Chris Wilson. ___ time-nuts mailing 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] EIP545A 18GHz counter query
29/11/2012 09:30 The replacement for the missing U6 chip arrived this morning and it now completes the 200 MHz self test It will read up to the limit of my frequency generator on Band 3 which is only 1040 MHz, but looks promising. Band 2 also works, but seemingly has an anomaly. I cannot get Band 2 to read below 185.000 MHz. If I input 184.900 it won't read it and displays zeros. 185 and up is OK... Weird. It should read from 10 MHz up to 1 GHz. It'll go to 1 GHz plus AOK. Band 1 appears to work fine. These tests are with both my GPS referenced external standard and the internal reference used. So Band 2 appears to have a further issue. Will refer to the manual and see if I can fathom it out. Any ideas as to why Band 2 will only read from 185 MHz upwards please? Thanks. 29/11/2012 15:53 OK, I may be doing something foolish. David Partridge was able to supply one of his last remaining frequency dividers to me, for use with my TB GPS standard. It works perfectly and is now in a nice enclosure feeding a small array of BNC sockets on my shack wall. I take the 10 MHz output of the Thunderbolt into David's frequency divider: http://www.perdrix.co.uk/FrequencyDivider/index.html I have the 10MHz output from David's divider feeding the counter. When fed from this the Band 2 seems unreliable starting at 10MHz. If I feed it 10Mhz at 50mV from my sig gen it starts reliably. Is it a mismatch from the divider, or has it perhaps not got enough drive level? -- Best Regards, Chris Wilson. ___ time-nuts mailing 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] EIP545A 18GHz counter query
Chris wrote: I have the 10MHz output from David's divider feeding the counter. When fed from this the Band 2 seems unreliable starting at 10MHz. If I feed it 10Mhz at 50mV from my sig gen it starts reliably. Is it a mismatch from the divider, or has it perhaps not got enough drive level? First, what does the counter manufacturer's specification say with respect to acceptable signals at the external reference input? Second, what happens if you feed the TB output directly to the counter's reference input? IIRC, the outputs of the Partridge divider are 5V TTL from a ~50 ohm source, so low peak-to-peak signal amplitude should not be an issue. If anything, the divider could be overdriving the counter's reference input. Note that the TTL signal ranges from 0V to ~+5V and does not cross ground -- if the counter is expecting the reference to be bipolar (i.e., if it switches on a zero-cross), it may not respond reliably to TTL levels. Beyond that, depending on how the counter terminates the external reference line, you may have steps or ringing at the reference input (see the thread on terminations). Look at the counter's reference input with a high-impedance (divide by 10) scope probe to see what the feed looks like there. Best regards, Charles ___ time-nuts mailing 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] Z3805 incident
Sorry, Ulli, if I'm not quite with it, today... Which one is the bad guy now, the oven or the RX? We can't decide that, can we? IMHO does neither the EFC nor the PPS TI response tell us, whether the RX or the Crystal caused this peak, what we see is just the difference time between them. Or does the time constant reveal more? Thank you Volker Am 29.11.2012 08:28, schrieb Ulrich Bangert: Volker, please note that much of the clear text in the status information is generated by Z38XX itself to make it easier to read. 2012-11-28 10:01:40: The last Smartclock Status is undefined 2012-11-28 10:01:40: Starting with status LOCK for example means that Z38XX is unaware of the receiver status and assumes that the status is locked. 73s de Ulli, DF6JB -Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Volker Esper Gesendet: Mittwoch, 28. November 2012 22:24 An: Discussion of precise time and frequency measurement Betreff: [time-nuts] Z3805 incident When looking at the PPS TI vs. time curve today I felt kind of appalled - a big incident peak (not an outlier) on the curve! See picture. What happened to my Z3805? Any idea? No entry in the error log, the staus log says 2012-11-28 10:01:30: The Smartclock Status has changed to LOC 2012-11-28 10:01:40: The last Smartclock Status is undefined 2012-11-28 10:01:40: Starting with status LOCK Thanks Volker ___ time-nuts mailing 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] Frequency generator and counter on same external reference
Two rules to follow. 1 - use well shielded cables for the 10 MHz distribution if you wish to receive WWV 10 off the air. The skinny cables used for Ethernet generally don't cut it. 2. Most instruments have a high impedance 10 MHz input. Put them in the middle with T connectors left over from your 10 base T days. If you have an instrument that terminates the 10 MHz input, it goes last. Otherwise use a terminator at the end. I have an Advantest spectrum analyzer, HP selective level meter, Racal-Dana counter, Flexradio 1500, and Gigatronics generator daisy chained from a Thunderbolt. Plenty of signal, and the fat (well shielded) cables let me listen to WWV. On 11/29/2012 07:01 AM, Tom Clifton wrote: Good heavens, no. By doing so, they both have the same reference and the measuremets actually means something. I have a stack of HP stuff (3586, 3386 and assorted counters) all T'd off my Tbolt without issue. The only caveat is that you don't put too much stuff across the T-bolt output so as to load it down to the point where some device can't get clocking. Before you hit that point, you may need a high quality (low jitter) distribution amp in the timing chain. Date: Thu, 29 Nov 2012 09:42:39 + From: Chris Wilson Subject: [time-nuts] Frequency generator and counter on same external reference? I am repairing an 18GHz counter and it has a 10MHz external reference port. So does my elderly Marconi 2019A sig gen. Is there any potential issue having them both referenced off my Thunderbolt GPS referenced standard, at the same time? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chuck Forsberg WA7KGX N2469R c...@omen.com www.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] EIP545A 18GHz counter query
Hmmm you run the risk of deafening the counter with 5Vpp (2.5V into 50R). Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Wilson Sent: 29 November 2012 15:57 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] EIP545A 18GHz counter query 29/11/2012 09:30 The replacement for the missing U6 chip arrived this morning and it now completes the 200 MHz self test It will read up to the limit of my frequency generator on Band 3 which is only 1040 MHz, but looks promising. Band 2 also works, but seemingly has an anomaly. I cannot get Band 2 to read below 185.000 MHz. If I input 184.900 it won't read it and displays zeros. 185 and up is OK... Weird. It should read from 10 MHz up to 1 GHz. It'll go to 1 GHz plus AOK. Band 1 appears to work fine. These tests are with both my GPS referenced external standard and the internal reference used. So Band 2 appears to have a further issue. Will refer to the manual and see if I can fathom it out. Any ideas as to why Band 2 will only read from 185 MHz upwards please? Thanks. 29/11/2012 15:53 OK, I may be doing something foolish. David Partridge was able to supply one of his last remaining frequency dividers to me, for use with my TB GPS standard. It works perfectly and is now in a nice enclosure feeding a small array of BNC sockets on my shack wall. I take the 10 MHz output of the Thunderbolt into David's frequency divider: http://www.perdrix.co.uk/FrequencyDivider/index.html I have the 10MHz output from David's divider feeding the counter. When fed from this the Band 2 seems unreliable starting at 10MHz. If I feed it 10Mhz at 50mV from my sig gen it starts reliably. Is it a mismatch from the divider, or has it perhaps not got enough drive level? -- Best Regards, Chris Wilson. ___ time-nuts mailing 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] EIP545A 18GHz counter query
OK. It maybe time for the hair dryer and freeze spray. Also, try re-seating any socketed chips. -John == It sounds like a SW limit, not hardware. Silly question: Have you read the manual? -John 29/11/2012 15:31 Hi John, will re read the section on limits, but please see my reply to Chuck I just posted. Cheers. -- Best Regards, Chris Wilson. ___ time-nuts mailing 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] Best phase detector / mixer for 100MHz?
At 03:56 PM 11/29/2012 +, you wrote: By theory, yes... but we use a sound card with a lot of flicker noise on the lower end, also we have the 10...20Hz low freq. cutoff due the usage of a servo / single 5V power. Also the raising noise below 100Hz (ADC serve noise on the ADC power / input circuit) limits the performance. One way to avoid the problem in the 1/f noise region is to avoid it. Mix down to a few kHz and analyze you signal or if you must mix down to DC then chop it to bring it up to a kHz or so and analyze it using a program such as spectrum lab or in software to internally mix back down to DC using software digital mixer and then analyze. You can use a MOSFET analog switch to chop the signal. When you chop it you will have an carrier with upper and lower sidebands. You can simply take the FFT data and either shift the bins making the carrier (chopping frequency) the Zero or DC bin or even better yet add the upper and lower sidebands so that you get a 3db improvement in S/N. I will be db since the sidebands are identical mirror of each other, ie voltage doubles when they are added increasing the signal by 6db but noise introduced by electronics on upper and lower sidebands are not coherent and only increases by 3db. 73 Bill wa4lav ___ time-nuts mailing 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] EIP545A 18GHz counter query
Chris wrote: I have the 10MHz output from David's divider feeding the counter. When fed from this the Band 2 seems unreliable starting at 10MHz. If I feed it 10Mhz at 50mV from my sig gen it starts reliably. Is it a mismatch from the divider, or has it perhaps not got enough drive level? First, what does the counter manufacturer's specification say with respect to acceptable signals at the external reference input? Second, what happens if you feed the TB output directly to the counter's reference input? IIRC, the outputs of the Partridge divider are 5V TTL from a ~50 ohm source, so low peak-to-peak signal amplitude should not be an issue. If anything, the divider could be overdriving the counter's reference input. Note that the TTL signal ranges from 0V to ~+5V and does not cross ground -- if the counter is expecting the reference to be bipolar (i.e., if it switches on a zero-cross), it may not respond reliably to TTL levels. Beyond that, depending on how the counter terminates the external reference line, you may have steps or ringing at the reference input (see the thread on terminations). Look at the counter's reference input with a high-impedance (divide by 10) scope probe to see what the feed looks like there. Best regards, Charles 29/11/2012 17:32 It's definitely playing up, and I don't think I have it right with regard to it being because I am feeding it from David's divider. I let it go cold this afternoon and have just come to it now. Even with the signal into Band 2 direct from my sig gen at 1 volt it doesn't start counting unless I go to, or over, 185 MHz. Band 3 is fine from cold, as is Band 1. I'll get some freeze spray and see if I can isolate any part. I'll also have a go with the air line. So near to being fine, must be something pretty minor? Band 2 should work from -20dbm (22mV RMS) right across its 10 MHz to 1 GHz range according to the manual. Even with 190 MHz into it it takes at least 30mV to start triggering, sometimes up to 40 mV. 40 mV will reliably fire it across its full range once it warms up a bit. Band 1 specs are 22 mV from 10Hz to 1 GHz, and that band triggers with just 15 mV at 10 MHz, but needs 25 mV at 100 MHz. Band 3 specs are 12 mV at 1 GHz to 1.2 GHz (needs 15 mV @ 1GHz) 1.2 to 12.4 GHz should trigger at 7 mV but my sig gen stops at 1040 MHz so can't test. Thanks for your input Charles. -- Best Regards, Chris Wilson. ___ time-nuts mailing 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] EES RC 1454 100DB MSF/GPS clock
Hi all, I recently gave in and bought one of the EES (european electronic systems) RC1454 Radio Clock units that have been on ebay.co.uk for a while. The one I snagged came with a GPS antenna unit. The main unit has a label saying GPS Modified The main box appears to be a MSF receiver but has no obvious power connector, just two rectangular multiway sockets, a 15W D plug and two BNC's. It is a 2U high card frame with 15 PCBS and a LED display on th front. Vintage is late 1990's and both units look like new. The GPS unit has an early Oncore (R1211A) receiver and a PCB with a CPU etc. Two BNC' marked MSF ANT and RX looks like a mod for either MSF or GPS time. Does anyone have any information on these beore I get into major reverse engineering? Robert G8RPI. ___ time-nuts mailing 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] Frequency generator and counter on same external reference
Kind of funny you bring that up. I have an old Fluke 1900A counter (plastic case) that radiates 10mhz clock that deafens my receiver. It only took me a week to find the intermittent source of interference Boy, did I feel stupid... - Date: Thu, 29 Nov 2012 08:45:04 -0800 From: Chuck Forsberg Subject: Re: Frequency generator and counter on same external reference Two rules to follow. 1 - use well shielded cables for the 10 MHz distribution if you wish to receive WWV 10 off the air ... ___ time-nuts mailing 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] Special integration capacitors
I'm selling a few of these cards. See eBay item 321033088669 I also have a quantity of the bath tub style from HP 5061 Cesium standards. (If I remember 5, 8, and 3uf available) Built specially for long time constant integrators. Corby OVERSTOCK ipads: $30.93 Get 32GB Apple iPad for as low as $30.93. Limit 1.Day. Grab yours Now! http://thirdpartyoffers.juno.com/TGL3141/50b7b8504921c3850534ast04duc ___ time-nuts mailing 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] EES RC 1454 100DB MSF/GPS clock
Hi Robert For some reason I missed these until you mentioned them but have just taken a look and am reminded very much of the similarly modified and boxed EES 100s that Connect Distribution were selling around 5 years ago. Whilst this looks to be a much later unit both EES and Radiocode clocks do seem to have survived for an awful long time without too many significant revisions to their hardware, internal hardware anyway:-) I've seen a similar connector on one version of the RC060s but even that mainly used conventional D connectors. From what I remember of the antenna modules on the EES 100s I got the impression that the interface processor board extracted the timing information from the GPS signal and converted it into an MSF compatible signal to feed the EES 100. I'm sure they didn't frequency convert from L band to 60KHz but just took the GPS data and started from fresh to generate their own MSF compatible signal using that data. I never tried to use one of the modified units straight from MSF but will dig one out and try it, I don't think there was very much of a modification to the MSF receiver other than whatever was required to accept another 60KHz signal. I suspect all the hard work was done in the antenna module and the MSF unit was just used as decoder and display for the converted signal. I may have missed something, nothing unusual there then:-), but it always struck me as a rather odd way of accessing and displaying GPS timing data, unless initially there was some pressure to find a quick fix utilising existing approved equipment. Regards Nigel GM8PZR In a message dated 29/11/2012 18:58:47 GMT Standard Time, robert8...@yahoo.co.uk writes: Hi all, I recently gave in and bought one of the EES (european electronic systems) RC1454 Radio Clock units that have been on ebay.co.uk for a while. The one I snagged came with a GPS antenna unit. The main unit has a label saying GPS Modified The main box appears to be a MSF receiver but has no obvious power connector, just two rectangular multiway sockets, a 15W D plug and two BNC's. It is a 2U high card frame with 15 PCBS and a LED display on th front. Vintage is late 1990's and both units look like new. The GPS unit has an early Oncore (R1211A) receiver and a PCB with a CPU etc. Two BNC' marked MSF ANT and RX looks like a mod for either MSF or GPS time. Does anyone have any information on these beore I get into major reverse engineering? Robert G8RPI. ___ time-nuts mailing 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] Special integration capacitors
Is that ADO27B op-amp module on the PCB the same one used in the degausser for the HP 5061 high performance tube? Robert G8RPI. From: cdel...@juno.com cdel...@juno.com To: time-nuts@febo.com Sent: Thursday, 29 November 2012, 19:32 Subject: [time-nuts] Special integration capacitors I'm selling a few of these cards. See eBay item 321033088669 I also have a quantity of the bath tub style from HP 5061 Cesium standards. (If I remember 5, 8, and 3uf available) Built specially for long time constant integrators. Corby OVERSTOCK ipads: $30.93 Get 32GB Apple iPad for as low as $30.93. Limit 1.Day. Grab yours Now! http://thirdpartyoffers.juno.com/TGL3141/50b7b8504921c3850534ast04duc ___ time-nuts mailing 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] EIP545A 18GHz counter query
Chris wrote: Band 2 should work from -20dbm (22mV RMS) right across its 10 MHz to 1 GHz range according to the manual. Even with 190 MHz into it it takes at least 30mV to start triggering, sometimes up to 40 mV. 40 mV will reliably fire it across its full range once it warms up a bit. Band 1 specs are 22 mV from 10Hz to 1 GHz, and that band triggers with just 15 mV at 10 MHz, but needs 25 mV at 100 MHz. Band 3 specs are 12 mV at 1 GHz to 1.2 GHz (needs 15 mV @ 1GHz) Ahh, I had missed that you were feeding the 10 MHz from the divider to the *measurement* inputs. It sounds like a triggering issue. Is the trigger coupling switchable from DC to AC, and is it adjustable for trigger level? It is not unusual for the trigger point to drift a bit as a counter warms up, but at any temperature you should be able to find settings that will allow it to trigger on inputs at least close to the minimum the manufacturer specifies. The figures you are seeing are not way out of bounds, especially if the trigger coupling and level have not been adjusted for optimum triggering. Again, note that the divider output is unipolar (positive-only, does not cross 0V). With a TTL input, you should get good, stable triggering with the trigger coupling set to DC and the trigger level set to ~+0.5V on the positive-going edge. With sine-wave inputs, you may get best results with AC coupling and a trigger level at or near 0V. Look under triggering in the manual to see what the manufacturer recommends. It's just like the triggering on an oscilloscope, if that helps -- what you would do to get a stable scope display is also what you need to do to get a stable frequency reading. Best regards, Charles ___ time-nuts mailing 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] Z3805 incident
On 29 Nov, 2012, at 02:32 , Charles P. Steinmetz charles_steinm...@lavabit.com wrote: This is a classic crystal jump. The crystal changed its frequency magically from one second to the next and the software compensated for it Here is another example of a 3805 having a bad moment. For just about two minutes, it reported a phase jump of nearly 3 uS and then immediately fell back nearly to its previous baseline, settling to the baseline in about an hour and not requiring any longer-term change of the EFC voltage. This does not look like a typical crystal frequency shift to me, but I cannot rule that out. It looks more like what I'd expect to see if I set the cable delay to 3 uS for 2 minutes, then back to 0. I think I would be more likely to call this one, where the crystal jumps to another frequency for a while and then jumps back to about what it was, a classic crystal jump. I've seen this before, though not as large as the change you show. I hear these raise hell when they try to use PTP to transmit telecom-quality timing over asynchronous ethernet because it is hard to run a PTP control loop tight enough (i.e. at a high enough data rate) to correct that before it does damage. I think the other problem, with the crystal jumping to another frequency and apparently staying there (I'm assuming it hasn't jumped back), could have a broader range of causes. Dennis Ferguson ___ time-nuts mailing 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] Loran
Rich Did not see anyone respond. Are you still hearing the signal? Paul WB8TSL On Mon, Nov 26, 2012 at 6:59 PM, Rich and Marcia Putz rp...@bnin.netwrote: Hi all; I 'm hearing Loran C signals here in northern Indiana this evening, I guessing from New Jersey. Anyone else hearing these? Rich __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Special integration capacitors
One of those items that I'm only getting displayed when I already have the item no. Even on ebay.com and having selected shipping to a US address. Apparently, those folks have found new ways to avoid making millions of US$ of selling fees, as well as brilliantly cutting their customers business to size. I only get a HP power cord listed. Adrian cdel...@juno.com schrieb: I'm selling a few of these cards. See eBay item 321033088669 I also have a quantity of the bath tub style from HP 5061 Cesium standards. (If I remember 5, 8, and 3uf available) Built specially for long time constant integrators. Corby OVERSTOCK ipads: $30.93 Get 32GB Apple iPad for as low as $30.93. Limit 1.Day. Grab yours Now! http://thirdpartyoffers.juno.com/TGL3141/50b7b8504921c3850534ast04duc ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Special integration capacitors
Well thas strange I looked at his offer and I see the tracor board and 2 caps? On Thu, Nov 29, 2012 at 6:36 PM, Adrian rfn...@arcor.de wrote: One of those items that I'm only getting displayed when I already have the item no. Even on ebay.com and having selected shipping to a US address. Apparently, those folks have found new ways to avoid making millions of US$ of selling fees, as well as brilliantly cutting their customers business to size. I only get a HP power cord listed. Adrian cdel...@juno.com schrieb: I'm selling a few of these cards. See eBay item 321033088669 I also have a quantity of the bath tub style from HP 5061 Cesium standards. (If I remember 5, 8, and 3uf available) Built specially for long time constant integrators. Corby __**__ OVERSTOCK ipads: $30.93 Get 32GB Apple iPad for as low as $30.93. Limit 1.Day. Grab yours Now! http://thirdpartyoffers.juno.**com/TGL3141/**50b7b8504921c3850534ast04duchttp://thirdpartyoffers.juno.com/TGL3141/50b7b8504921c3850534ast04duc __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Z3805 incident
...and I should see the loop time constant in the ADEV, too - if that is the case, the time constant should be about 2000 s, shouldn't it? (see picture) Volker Am 29.11.2012 05:35, schrieb Said Jackson: Volker, This is a classic crystal jump. The crystal changed its frequency magically from one second to the next and the software compensated for it You can nicely see the time constant of the loop.. Bye Said Sent From iPhone On Nov 28, 2012, at 13:24, Volker Esperail...@t-online.de wrote: When looking at the PPS TI vs. time curve today I felt kind of appalled - a big incident peak (not an outlier) on the curve! See picture. What happened to my Z3805? Any idea? No entry in the error log, the staus log says 2012-11-28 10:01:30: The Smartclock Status has changed to LOC 2012-11-28 10:01:40: The last Smartclock Status is undefined 2012-11-28 10:01:40: Starting with status LOCK Thanks Volker DF9PL_GPSDO_2_20121128_2108_PPS-TI_b.jpg ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. attachment: DF9PL_GPSDO_1_20121128_2109_sigma(tau)_b.jpg___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Special integration capacitors
Sadly, no. Different number and it looks like pin-out as well. On Nov 29, 2012, at 6:06 PM, Robert Atkinson robert8...@yahoo.co.uk wrote: Is that ADO27B op-amp module on the PCB the same one used in the degausser for the HP 5061 high performance tube? Robert G8RPI. From: cdel...@juno.com cdel...@juno.com To: time-nuts@febo.com Sent: Thursday, 29 November 2012, 19:32 Subject: [time-nuts] Special integration capacitors I'm selling a few of these cards. See eBay item 321033088669 I also have a quantity of the bath tub style from HP 5061 Cesium standards. (If I remember 5, 8, and 3uf available) Built specially for long time constant integrators. Corby OVERSTOCK ipads: $30.93 Get 32GB Apple iPad for as low as $30.93. Limit 1.Day. Grab yours Now! http://thirdpartyoffers.juno.com/TGL3141/50b7b8504921c3850534ast04duc ___ time-nuts mailing 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] EIP545A 18GHz counter query
Could be either. What is the band width of Band 2? I am not in front of my counter. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Wilson Sent: Thursday, November 29, 2012 9:57 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] EIP545A 18GHz counter query 29/11/2012 09:30 The replacement for the missing U6 chip arrived this morning and it now completes the 200 MHz self test It will read up to the limit of my frequency generator on Band 3 which is only 1040 MHz, but looks promising. Band 2 also works, but seemingly has an anomaly. I cannot get Band 2 to read below 185.000 MHz. If I input 184.900 it won't read it and displays zeros. 185 and up is OK... Weird. It should read from 10 MHz up to 1 GHz. It'll go to 1 GHz plus AOK. Band 1 appears to work fine. These tests are with both my GPS referenced external standard and the internal reference used. So Band 2 appears to have a further issue. Will refer to the manual and see if I can fathom it out. Any ideas as to why Band 2 will only read from 185 MHz upwards please? Thanks. 29/11/2012 15:53 OK, I may be doing something foolish. David Partridge was able to supply one of his last remaining frequency dividers to me, for use with my TB GPS standard. It works perfectly and is now in a nice enclosure feeding a small array of BNC sockets on my shack wall. I take the 10 MHz output of the Thunderbolt into David's frequency divider: http://www.perdrix.co.uk/FrequencyDivider/index.html I have the 10MHz output from David's divider feeding the counter. When fed from this the Band 2 seems unreliable starting at 10MHz. If I feed it 10Mhz at 50mV from my sig gen it starts reliably. Is it a mismatch from the divider, or has it perhaps not got enough drive level? -- Best Regards, Chris Wilson. ___ time-nuts mailing 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] Z3805 incident
HI Some simple empirical data: 1) Jumps tend to get further apart as the oscillator ages. 2) AT's have larger jumps than SC's. 3) A typical SC jump is below 1x10^-9 4) It's not a lot of things (spurs, drive, temperature, load,stress, micro-fractures, plating defects) if you need to explain all cases = they don't explain all events 5) It can be a lot of things (spurs, drive, temperature, load, stress, micro-fractures, plating defects) in some cases = they do explain some events The first published data I have seen on jumps is in a Fairchild Semiconductor App note from the late 60's / early 70's. They built a JFET based oscillator and it jumped…. Bob On Nov 29, 2012, at 7:30 PM, Volker Esper ail...@t-online.de wrote: ...imho it has indeed jumped back, see the picture of 1643 GMT today. You recognize the peak down yesterday at about 1900 GMT, then a smaller peak up at about 2300 GMT and - after having a troubled night - again a peak up. The EFC voltage now is nearly the same as prior to the impact series. I suppose it's actually a crystal jump. In 1997 HP wrote in it's AN 200-2 (Fundamentals of Quartz Oscillators): ...Crystals having unwanted signals could also shift from one resonate point to another producing a frequency jump which would be an undesirable effect. IEEE has some experience with that phenomenon, too. An article from 1996 can be found in their Digital Library http://ieeexplore.ieee.org/xpl/login.jsp?tp=arnumber=559877url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel3%2F4090%2F12100%2F00559877.pdf%3Farnumber%3D559877 wich deals with that issue: In this paper recently classified intermittent and discrete frequency jump phenomena are briefly reviewed and currently not well understood abrupt frequency jump phenomena are analysed and discussed in detail. John R. Vig writes in his Quartz Crystal Resonators and Oscillators For Frequency Control and Timing Applications - A Tutorial (2004): It is the changes in the stresses, and the changes produced by the stresses that cause frequency instabilities. There exists evidence that, on a microscopic level, stress relief is not a continuous process. It can occur in bursts that can, possibly, contribute to noise and frequency jumps. Numerous articles discuss the effects of contamination and failures of the crystal clamp that obviously contribute to the phenomenon. Though very interesting stuff, that all sounds kind of academical to me. Now I know it could be possible, that my GPSDO suffers from that cause. However, since I don't know if or when or how often the effect recurs, I am the one, who has broken nights now... I'll keep a jealous watch over the diagrams... Volker Am 30.11.2012 00:14, schrieb Dennis Ferguson: On 29 Nov, 2012, at 02:32 , Charles P. Steinmetzcharles_steinm...@lavabit.com wrote: This is a classic crystal jump. The crystal changed its frequency magically from one second to the next and the software compensated for it Here is another example of a 3805 having a bad moment. For just about two minutes, it reported a phase jump of nearly 3 uS and then immediately fell back nearly to its previous baseline, settling to the baseline in about an hour and not requiring any longer-term change of the EFC voltage. This does not look like a typical crystal frequency shift to me, but I cannot rule that out. It looks more like what I'd expect to see if I set the cable delay to 3 uS for 2 minutes, then back to 0. I think I would be more likely to call this one, where the crystal jumps to another frequency for a while and then jumps back to about what it was, a classic crystal jump. I've seen this before, though not as large as the change you show. I hear these raise hell when they try to use PTP to transmit telecom-quality timing over asynchronous ethernet because it is hard to run a PTP control loop tight enough (i.e. at a high enough data rate) to correct that before it does damage. I think the other problem, with the crystal jumping to another frequency and apparently staying there (I'm assuming it hasn't jumped back), could have a broader range of causes. Dennis Ferguson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. DF9PL_GPSDO_2_20121129_2137_PPS-TI.jpgDF9PL_GPSDO_2_20121129_1643_PPS-TI.jpg___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] Termination talk
You will never find a more wretched hive of scum and villainy... 'Ben' Kenobi describing the Mos Eisley spaceport -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Volker Esper Sent: Thursday, November 29, 2012 07:20 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Termination talk ...yeah - it's better not to know those people ;-) ... Am 29.11.2012 08:28, schrieb Ulrich Bangert: Simon, ...which prefers to remain anonymous... sounds as if it were a group of criminals or so. Best regards Ulrich Bangert -Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von M. Simon Gesendet: Mittwoch, 28. November 2012 23:53 An: time-nuts@febo.com Betreff: [time-nuts] Termination talk I was going to post an anecdote about termination to the list and then thought that the piece would make a great column. It did. My magazine featured it in one of its daily mailings. If you want to check it out: http://www.ecnmag.com/blogs/2012/11/long-lines-pcb Simon Engineering is the art of making what you want from what you can get at a profit. ___ time-nuts mailing 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] Best phase detector / mixer for 100MHz?
Bill, One way to avoid the problem in the 1/f noise region is to avoid it. Mix down to a few kHz and analyze you signal This is a good point! Using my SW (www.hpw-works.com) simple set the x-scaling to a center frequency bandwidth of your choice with enough space in the lower region. This is implemented out of the box. It's like a measurement using the d-jitter but with a costume center frequency. See also the pictures on my homepage with zooming into the 0.005 Hz region using a large sample size. Required is that the source oscillators are stable... Hanspeter -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bill Fuqua Sent: Donnerstag, 29. November 2012 18:02 To: time-nuts@febo.com Subject: Re: [time-nuts] Best phase detector / mixer for 100MHz? At 03:56 PM 11/29/2012 +, you wrote: By theory, yes... but we use a sound card with a lot of flicker noise on the lower end, also we have the 10...20Hz low freq. cutoff due the usage of a servo / single 5V power. Also the raising noise below 100Hz (ADC serve noise on the ADC power / input circuit) limits the performance. One way to avoid the problem in the 1/f noise region is to avoid it. Mix down to a few kHz and analyze you signal or if you must mix down to DC then chop it to bring it up to a kHz or so and analyze it using a program such as spectrum lab or in software to internally mix back down to DC using software digital mixer and then analyze. You can use a MOSFET analog switch to chop the signal. When you chop it you will have an carrier with upper and lower sidebands. You can simply take the FFT data and either shift the bins making the carrier (chopping frequency) the Zero or DC bin or even better yet add the upper and lower sidebands so that you get a 3db improvement in S/N. I will be db since the sidebands are identical mirror of each other, ie voltage doubles when they are added increasing the signal by 6db but noise introduced by electronics on upper and lower sidebands are not coherent and only increases by 3db. 73 Bill wa4lav ___ time-nuts mailing 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.
