Re: [time-nuts] TPLL secret reveled
Bill, I think I have already shown my position on this whole matter from my previous posts and understand what Warren is alluding to but I'm just trying to assist him make his case in a way that is acceptable to other members on this list. On 10 June 2010 17:35, WB6BNQ wb6...@cox.net wrote: Steve, I have been following this thread and I think I can answer your question about the 1^-15 thing. What Warren is stating is what he feels the base resolution is, that being 1^-15 OR whatever your reference oscillator is worth. Well, taking the ref osc out of the equation, the 1^-15 seems to be an arbitrary floor if you assume that other items in the implementation are perfect and it's hard to see where this number comes from and it would have no floor in that situation. Obviously, limits in the measuring equipment and tolerances in the components used in the implementation will limit the accuracy of the system but that would have to be calculated to obtain a true measure of the limits of this. The key phrase is OR. . . WORTH. Obviously if you had a high quality H-maser or perhaps a Cesium Fountain then you may be able to reach his claimed 1^-15. Otherwise you are stuck with what you got on hand. Firstly, the design of the TPLL requires that the reference oscillator is able to be controlled such that it tightly matches the frequency of the unknown oscillator. This will exclude most forms of high quality oscillators that you have mentioned. In fact, those high quality oscillators only show higher stability for long Tau and for the current range of Tau that this implementation has been tested, the humble, or perhaps not so humble, xtal is the best choice. That being said, a stability in the region of 1^-15 is not to be seen on an undisciplined xtal. So why can we not use a disciplined xtal, say, GPSDO? Well, the operation of the TPLL requires that the xtal is directly controlled by the PLL mixer output filter directly and that precludes a GPSDO being also able to control the xtal frequency, IE. the two are mutually exclusive. What I have tried to say in my posting about this base accuracy is that let's not get too stuck on this number because more harm than good can come from this being taken literally by some members on this list and I felt that this claim would further add fuel to the fire. I agree with you on wanting to see an ACTUAL schematic detailed with real part numbers. Better detail on the software used would be nice as well. As far as his on-going argument with Bruce, well, at times it gets quite hard to follow. Particularly with Bruce refusing to insert BLANK lines above and below his responses. I think Warren is guilty of that too. It seems to be a breakdown in communication between those parties and that is why other have been trying to resolve these matters, both on-line and via PM, with both parties. I can see where Bruce was coming from in the beginning because Warren was definitely being obtuse with his explanations. All of that just makes it harder for us less informed to follow along. As are Bruce's cryptic comments which are frequently hard to understand unless you have his mind-set. Both parties have become entrenched in this matter and I feel that nothing can move forward between them except through intermediaries. Both have taken an abusive manner between each other and even others which have tried to assist in the matter and this has really not helped things. Bruce, I know you are striving for the best in your efforts. BUT, if Warren's method provides a GOOD ENOUGH approximation for us less endowed, then perhaps it has a place with stated caveats ? Bruce is, and always has been, a perfectionist, but that is not a bad thing. This is a time-nuts group, after all, where the pursuit of perfection is paramount and it is to that goal we should strive for. That being said, there is a place for lesser mortals to enjoy and expand their knowledge in this fascinating area without breaking the bank or being looked down upon by some. We are ALL here to learn, every single one of us, as if anyone thinks they know everything there is to know about this subject, a) they are miss-informed, and b) whay are they here. As to this method producing GOOD ENOUGH approximations, this has a very much a relative meaning to many people and these results in themselves will also have degrees of relevant meaning to different people. There are some limitations to the range that this tester can work over but many will be surprised to find that the accuracy over that range is al lot more than GOOD ENOUGH for their needs. Examination of the graphs that John posted shows a close correlation over quite a range between the two testers and outside this range, say, at the top end, drift in the reference oscillator pays it's toll in the results. If you have a reference osc xtal with very low noise and very low drift, you will get very good results, even over an extended range.
[time-nuts] HP Z3815A hookup
Hi! I just got a HP Z3815A but it seems like it is a bit of a challenge to hook it up. I see one large connector for some bus-structure, but don't know the pinning. There is also an 8 coax connector, where I suspect the antenna, 10 MHz, PPS and other generated frequencies pop out. The RS-232 on the front is obvious. I know there is a few SMBs inside, but it would be nice to get some practical hints from people playing with them before. Yes, the hockey-puck is there. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] TPLL secret reveled
Warren, I know you like my software and therefore please allow me to put my 50 cts. into the discussion: The reason that the simple TPLL works so good but is hard for some experts to accept, seems to come down to the fact that this method uses Frequency and not Phase to make the raw data log used to then calculate ADEV data. This belief is the biggest misconceptions of yours. No one has ever denied that correct ADEV values can be computed from frequency data and (as far as I believe) Allan came out with a formula for phase data and for frequency data at the same time. The problem is a bit more subtle but by far not out of the reach as a good technician as you. I would like to keep the topic of deadtime out of the discussion. Therefore please consider a situation where two old fashion frequency counters (the ones that were only counting) are synchronized in such a way that they produce frequency data at a Tau0 of 1 second without any deadtime, the first counter for second n then the second counter for second n+1 then the first counter for second n+2 and so on. If you feed the produced data into Allans frequency formula then you will get a perfect ADEV calculation out ouf it. The only drawback is that it will have a high noise floor because with the counters counting complete periods of the wave their effective resolution may be considered 1 period length of the wave. Now let us consider what the old fashioned counter REALLY does: Over a gate time of 1 second (identical to Tau0) it COUNTS the number of WHOLE periods. Basically the old fashioned counter does make an integrating phase measurement over the time integral Tau0. The result is not displayed in units of the phase domain but it units of the frequency domain but the key point is that the frequency measurement gathered this way contains the same information contents as if a phase measurement had taken place. Therefore it becomes clear immediately why one must use a slightly different formula for the frequency values but why otherwise everything we know from phase data is contained in in the frequency data as well. Next consider the case that the frequency of the DUT lineary changes with a negative slope during the first half of a second to a minimum at the center of the second and then changes with the same but positive slope so that at the end of the second the frequency is the same as at the beginning of the second. Clearly a phase measurement will reveal this behaviour and the old fashioned counter will as well. This is why we say that the phase measurement as well as the frequency measurement gathered this way are characteristic for the WHOLE of the second of Tau0. The next improvement to the old fashioned pure counter was the invention of subclock interpolation schemes. A counter using this works so: After the beginning of the gate time it waits of the next zero crossing and then measures the time up to the last zero crossing within the gate time with a fixed resolution of say 1 ns (like the well known Racal Dana 1992/1996/1998). The frequency value is then the result of a computation. If you consider this working principle you notice that this is even more a phase meter like thing than the original counter only thing. For that reason frequency measurements with a counter like that are suited as well for ADEV calculation. The next improvement in counter technology is applying tricks as not to measure a single time interval during the gate time but instead making thousands of time-delayed measurements and then applying statistics to it. The Agilent 53131/2 and the new Pendulum counters belong to this class. They deliver even more frequency resolution but is has been shown and discussed in another thread here why frequency measurements with these class of counters are NOT WELL suited for ADEV calculation. That is why we let them out. Once we have understood these facts let us return to the tight pll method. Let us consider what would happen with the above case with the frequency changing down and up lineary within one second. Well, since the pll tightly tracks the dut in frequency the loop voltage will be the exact copy in the voltage domain of what is happening in the frequency domain. The key point is that the integrating process that is involved in the nature of the counter only measurement and also in the improved counter measurement does NOT take place INSIDE the pll loop. Had you looked to the loop voltage at a Tau0 of 1 s you would not have noticed ANYTHING from the frequency changes because the loop voltage measurements deliver an instantaneous frequency information and not one that is characteristic for your Tau0. Because the loop voltage contains INSTANTANEOUS frequency information it is different from counter originated data and needs special treatment: It needs integration afterwards which in the original NIST method is applied by the voltage to frequency counter and the following impulse counter. The case of the
Re: [time-nuts] TPLL secret reveled
Ulrich, May I please tackle some points here please. Regarding Warren's implementation of the TPLL, these points have been covered before, several times, but there is obviously an inability for either Warren or myself to communicate effectively on these matters. On 10 June 2010 22:36, Ulrich Bangert df...@ulrich-bangert.de wrote: Warren, I know you like my software and therefore please allow me to put my 50 cts. into the discussion: The reason that the simple TPLL works so good but is hard for some experts to accept, seems to come down to the fact that this method uses Frequency and not Phase to make the raw data log used to then calculate ADEV data. This belief is the biggest misconceptions of yours. No one has ever denied that correct ADEV values can be computed from frequency data and (as far as I believe) Allan came out with a formula for phase data and for frequency data at the same time. The problem is a bit more subtle but by far not out of the reach as a good technician as you. The correct calculation of ADEV requires that the average of the variable be taken over a specific time interval. When you measure averaged frequency at specific time intervals of Tau0 this requirement is met. The measurement of phase data is taken over the current period of each waveform and therefore, assuming the waveform contains noise, each measurement will not be be spaced evenly at Tau0, it will be spaced at the current length of the period of the waveform which will vary with its noise component. To further make this point clear, even though the unknown frequency may be divided down to 1Hz for Tau0 = 1HZ, each successive measurement of phase data will occur at a time interval of 1s +- current noise component, this does not satisfy Allan's equation for AVAR/ADEV calculation. I would like to keep the topic of deadtime out of the discussion. Therefore please consider a situation where two old fashion frequency counters (the ones that were only counting) are synchronized in such a way that they produce frequency data at a Tau0 of 1 second without any deadtime, the first counter for second n then the second counter for second n+1 then the first counter for second n+2 and so on. If you feed the produced data into Allans frequency formula then you will get a perfect ADEV calculation out ouf it. The only drawback is that it will have a high noise floor because with the counters counting complete periods of the wave their effective resolution may be considered 1 period length of the wave. Agreed. Now let us consider what the old fashioned counter REALLY does: Over a gate time of 1 second (identical to Tau0) it COUNTS the number of WHOLE periods. Basically the old fashioned counter does make an integrating phase measurement over the time integral Tau0. The result is not displayed in units of the phase domain but it units of the frequency domain but the key point is that the frequency measurement gathered this way contains the same information contents as if a phase measurement had taken place. Therefore it becomes clear immediately why one must use a slightly different formula for the frequency values but why otherwise everything we know from phase data is contained in in the frequency data as well. The Allan equation specifically requires integrated values over a specified time interval. To include values outside of this specific time interval with the collection of phase data would be incorrect. By it's very nature, the collection of data in the phase domain does not lend itself to measurements at specified time intervals as the tail wags the dog. Frequency data in this case is taken over a specific gate time and it is this gate time which is kept constant, therefore the data is spaced at a specific time interval. Phase domain data is controlled by the length of the period of the waveform and so it is that which determines the time interval of the measurements. I can see what people are getting confused about because for a single cycle of a waveform, it is true that frequency = the reciprocal of the period but that is too simple when we look at calculating Allan Variance. Next consider the case that the frequency of the DUT lineary changes with a negative slope during the first half of a second to a minimum at the center of the second and then changes with the same but positive slope so that at the end of the second the frequency is the same as at the beginning of the second. Clearly a phase measurement will reveal this behaviour and the old fashioned counter will as well. This is why we say that the phase measurement as well as the frequency measurement gathered this way are characteristic for the WHOLE of the second of Tau0. Agreed, and this is a valid point which will come up later here. The next improvement to the old fashioned pure counter was the invention of subclock interpolation schemes. A counter using this works so: After the beginning of the gate time it
Re: [time-nuts] TPLL secret reveled
Ulrich Bangert wrote: The next improvement to the old fashioned pure counter was the invention of subclock interpolation schemes. A counter using this works so: After the beginning of the gate time it waits of the next zero crossing and then measures the time up to the last zero crossing within the gate time with a fixed resolution of say 1 ns (like the well known Racal Dana 1992/1996/1998). The frequency value is then the result of a computation. If you consider this working principle you notice that this is even more a phase meter like thing than the original counter only thing. For that reason frequency measurements with a counter like that are suited as well for ADEV calculation. I've always referred to these style counters as reciprocal counters.. (because the frequency is calculated as the reciprocal of the length of N periods of the input signal). They've been around at least since the 80s, especially for applications where you need short gate time, but measurement precision greater than 1/gate time. It was very popular for applications like intercept receivers in the signals intelligence area before straight digital processing (ADC and FFT) was practical. ___ time-nuts mailing 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] TPLL secret reveled
Steve, I do not want to comment the whole of your posting because I am tired of the discussion myself too. But if I read things like: The measurement of phase data is taken over the current period of each waveform and therefore, assuming the waveform contains noise, each measurement will not be be spaced evenly at Tau0, it will be spaced at the current length of the period of the waveform which will vary with its noise component. then I think that you have re-check your basic conceptions on frequency and phase measurements as well. Naturally the zero crossings of waves are NOT always on top of the measurement times as given by Tau0. Specially this fact is the case with heterodyne methods with beat frequencies of as low as 1 Hz where the zero crossings of the wave may be hundreds of milliseconds away from the measurement times as required by a given Tau0. But instead to conclude that phase measurements are not well suited for AD computations as YOU do, horology's simple answer to this is to compute phase values that are normalized to the epoch of the given Tau0 with VERY SIMPLE MATH as for example shown by Greenhall in http://ipnpr.jpl.nasa.gov/progress_report/42-143/143K.pdf Note that the main topic of this article is a different one but it explains how to handle the phase data correctly. The fact that almost all of the world is handling phase data while you seem to have the proof in your hands that this is completely wrong should have made you at least...say: Handle this case with care. Because in such a situation either winning the Nobel prize with it or to be committed into a closed ward are both possible outcomes of the claim. Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Steve Rooke Gesendet: Donnerstag, 10. Juni 2010 15:28 An: Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] TPLL secret reveled Ulrich, May I please tackle some points here please. Regarding Warren's implementation of the TPLL, these points have been covered before, several times, but there is obviously an inability for either Warren or myself to communicate effectively on these matters. On 10 June 2010 22:36, Ulrich Bangert df...@ulrich-bangert.de wrote: Warren, I know you like my software and therefore please allow me to put my 50 cts. into the discussion: The reason that the simple TPLL works so good but is hard for some experts to accept, seems to come down to the fact that this method uses Frequency and not Phase to make the raw data log used to then calculate ADEV data. This belief is the biggest misconceptions of yours. No one has ever denied that correct ADEV values can be computed from frequency data and (as far as I believe) Allan came out with a formula for phase data and for frequency data at the same time. The problem is a bit more subtle but by far not out of the reach as a good technician as you. The correct calculation of ADEV requires that the average of the variable be taken over a specific time interval. When you measure averaged frequency at specific time intervals of Tau0 this requirement is met. The measurement of phase data is taken over the current period of each waveform and therefore, assuming the waveform contains noise, each measurement will not be be spaced evenly at Tau0, it will be spaced at the current length of the period of the waveform which will vary with its noise component. To further make this point clear, even though the unknown frequency may be divided down to 1Hz for Tau0 = 1HZ, each successive measurement of phase data will occur at a time interval of 1s +- current noise component, this does not satisfy Allan's equation for AVAR/ADEV calculation. I would like to keep the topic of deadtime out of the discussion. Therefore please consider a situation where two old fashion frequency counters (the ones that were only counting) are synchronized in such a way that they produce frequency data at a Tau0 of 1 second without any deadtime, the first counter for second n then the second counter for second n+1 then the first counter for second n+2 and so on. If you feed the produced data into Allans frequency formula then you will get a perfect ADEV calculation out ouf it. The only drawback is that it will have a high noise floor because with the counters counting complete periods of the wave their effective resolution may be considered 1 period length of the wave. Agreed. Now let us consider what the old fashioned counter REALLY does: Over a gate time of 1 second (identical to Tau0) it COUNTS the number of WHOLE periods. Basically the old fashioned counter does make an integrating phase measurement over the time integral Tau0. The result is not displayed in units of the phase domain but it
Re: [time-nuts] TPLL secret reveled
Jim, pardon if I correct you: The reciprocal counters were an intermediate thing between the counting only and the subclock interpolating ones. A reciprocal counter would notice when a frequency measurement would be too imprecise due to an arkward relationship between that gate time and the frequency to be measured. With only a few zero crossings within the gate time a reciprocal counter would use the frequency to be measured as the source for its gate time and measure the frequency of its reference with that. The result is then back computed to the frequency to be measured. This principle has nothing to do with sub clock interpolation. Nevertheless it is true that once that the reciprocal principle has been introduced it has been used in all following technologies. Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von jimlux Gesendet: Donnerstag, 10. Juni 2010 15:55 An: Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] TPLL secret reveled Ulrich Bangert wrote: The next improvement to the old fashioned pure counter was the invention of subclock interpolation schemes. A counter using this works so: After the beginning of the gate time it waits of the next zero crossing and then measures the time up to the last zero crossing within the gate time with a fixed resolution of say 1 ns (like the well known Racal Dana 1992/1996/1998). The frequency value is then the result of a computation. If you consider this working principle you notice that this is even more a phase meter like thing than the original counter only thing. For that reason frequency measurements with a counter like that are suited as well for ADEV calculation. I've always referred to these style counters as reciprocal counters.. (because the frequency is calculated as the reciprocal of the length of N periods of the input signal). They've been around at least since the 80s, especially for applications where you need short gate time, but measurement precision greater than 1/gate time. It was very popular for applications like intercept receivers in the signals intelligence area before straight digital processing (ADC and FFT) was practical. ___ time-nuts mailing 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] Reciprocal Counters
Hi Jim, You're showing your age (you young whippersnapper!). ?? They've been around at least since the 80s,... Well, my General Radio 1159 Recipromatic Counters are from 1968 - built using those new transistor thingies and with the warm glow of Nixie tube readout. Best, Jerry Message: 2 Date: Thu, 10 Jun 2010 06:55:15 -0700 From: jimlux lt;jim...@earthlink.netgt; Subject: Re: [time-nuts] TPLL secret reveled To: Discussion of precise time and frequency measurement lt;time-nuts@febo.comgt; Message-ID: lt;4c10eec3.2030...@earthlink.netgt; Content-Type: text/plain; charset=ISO-8859-1; format=flowed Ulrich Bangert wrote: gt; gt; gt; gt; The next improvement to the old fashioned pure counter was the invention of gt; subclock interpolation schemes. A counter using this works so: After the gt; beginning of the gate time it waits of the next zero crossing and then gt; measures the time up to the last zero crossing within the gate time with a gt; fixed resolution of say 1 ns (like the well known Racal Dana gt; 1992/1996/1998). The frequency value is then the result of a computation. If gt; you consider this working principle you notice that this is even more a gt; phase meter like thing than the original counter only thing. For that reason gt; frequency measurements with a counter like that are suited as well for ADEV gt; calculation. gt; I've always referred to these style counters as reciprocal counters.. (because the frequency is calculated as the reciprocal of the length of N periods of the input signal). They've been around at least since the 80s, especially for applications where you need short gate time, but measurement precision greater than 1/gate time. It was very popular for applications like intercept receivers in the signals intelligence area before straight digital processing (ADC and FFT) was practical. -- ___ time-nuts mailing 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] Reciprocal Counters
Hi You could always set up a Beckman EPUT meter to do period and get effectively the same sort of result. No solid state in them at all. Full of warm glowing stuff (some of it glowed yellow, some of it glowed purple). Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of gsteinb...@aol.com Sent: Thursday, June 10, 2010 11:13 AM To: time-nuts@febo.com Subject: [time-nuts] Reciprocal Counters Hi Jim, You're showing your age (you young whippersnapper!). ?? They've been around at least since the 80s,... Well, my General Radio 1159 Recipromatic Counters are from 1968 - built using those new transistor thingies and with the warm glow of Nixie tube readout. Best, Jerry Message: 2 Date: Thu, 10 Jun 2010 06:55:15 -0700 From: jimlux lt;jim...@earthlink.netgt; Subject: Re: [time-nuts] TPLL secret reveled To: Discussion of precise time and frequency measurement lt;time-nuts@febo.comgt; Message-ID: lt;4c10eec3.2030...@earthlink.netgt; Content-Type: text/plain; charset=ISO-8859-1; format=flowed Ulrich Bangert wrote: gt; gt; gt; gt; The next improvement to the old fashioned pure counter was the invention of gt; subclock interpolation schemes. A counter using this works so: After the gt; beginning of the gate time it waits of the next zero crossing and then gt; measures the time up to the last zero crossing within the gate time with a gt; fixed resolution of say 1 ns (like the well known Racal Dana gt; 1992/1996/1998). The frequency value is then the result of a computation. If gt; you consider this working principle you notice that this is even more a gt; phase meter like thing than the original counter only thing. For that reason gt; frequency measurements with a counter like that are suited as well for ADEV gt; calculation. gt; I've always referred to these style counters as reciprocal counters.. (because the frequency is calculated as the reciprocal of the length of N periods of the input signal). They've been around at least since the 80s, especially for applications where you need short gate time, but measurement precision greater than 1/gate time. It was very popular for applications like intercept receivers in the signals intelligence area before straight digital processing (ADC and FFT) was practical. -- ___ time-nuts mailing 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] Loran C TOA change
Hello! Thanks to a smart member of this group, I am being able to receive consistently the SOUSTONS X-Ray slave of the European LESSAY (6731) chain with my Austron 2000C. After more than a week of continuous 1PPS phase comparaison between my TBolt and Soustons, with an absolute maximum deviation of +-0.3 uS, I noticed yesterday, 2010 June 09, a jump of -4.7 uS. The event exact epoch was not recorded.The new phase stills. I would like to understand the reason for that jump: - Was there some system time correction introduced? - Who in Europe is in charge of maintaining the chains? Your comments and information would be very much appreciated. Thanks in advance, Antonio CT1TE ___ time-nuts mailing 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 C TOA change
Hi +/- 300 ns is doing quite well with a 2000C. How far are you from the SOUSTONS station? At least here in the US, they sometimes would do odd things to the slaves on a given chain. Chain masters always *seemed* to less likely to have strange jumps in them. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of asma...@fc.up.pt Sent: Thursday, June 10, 2010 12:33 PM To: time-nuts@febo.com Subject: [time-nuts] Loran C TOA change Hello! Thanks to a smart member of this group, I am being able to receive consistently the SOUSTONS X-Ray slave of the European LESSAY (6731) chain with my Austron 2000C. After more than a week of continuous 1PPS phase comparaison between my TBolt and Soustons, with an absolute maximum deviation of +-0.3 uS, I noticed yesterday, 2010 June 09, a jump of -4.7 uS. The event exact epoch was not recorded.The new phase stills. I would like to understand the reason for that jump: - Was there some system time correction introduced? - Who in Europe is in charge of maintaining the chains? Your comments and information would be very much appreciated. Thanks in advance, Antonio CT1TE ___ time-nuts mailing 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] High reverse isolation amplifier
I have purchased a few of the Z1B base kits from Clifton Labs, Jack Smith and am very impressed by them. I am using them as isolation amps in a DMTD unit. At 5Mhz the reverse isolation is -110db and at 10Mhz it's better than -100. Stringing two in series would be overkill but would give you even more isolation. (no idea how you could begin to measure the reverse isolation of the two in series!) see: http://www.cliftonlaboratories.com/z1_buffer_amp.htm Corby Dawson Try this Weight Loss Trick Simple weight loss secret to lose 12 pounds in 30 days http://thirdpartyoffers.juno.com/TGL3141/4c112e33d320051cd1m04duc ___ time-nuts mailing 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] TPLL secret reveled
Fact #1) the TPLL uses Freq not phase, Warren, can you please clarify. From what I can see it actually uses a Minicircuits phase detector, right? That suggests what is being observed is a phase difference between the DUT and the REF, not a frequency difference. That analog phase measurement is then filtered and amplified into a pre-calibrated EFC correction to the REF which over a short time reduces the phase difference as seen by the phase detector. The digital stream comes from an ADC is connected to the EFC. So what does it mean to say TPLL uses Freq not phase? It looks to me like it uses both. /tvb ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Thunderbolt not seeing satellites
I'm not sure of the required power spec, but 28V may be too low. These were meant to run off a telco power bus (nominal 48V). I run mine at 40V (from a Tek PS503A mounted in a TM501 mainframe, unit connected across the + and - supply terminals, outputs set to +/- 20V). It won't run at 28V. Input voltage to the poor performing unit is about 28VDC. _ The New Busy is not the old busy. Search, chat and e-mail from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:WL:en-US:WM_HMP:042010_3 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt not seeing satellites
In a message dated 10/06/2010 23:34:05 GMT Daylight Time, hol...@hotmail.com writes: I'm not sure of the required power spec, but 28V may be too low. These were meant to run off a telco power bus (nominal 48V). I run mine at 40V (from a Tek PS503A mounted in a TM501 mainframe, unit connected across the + and - supply terminals, outputs set to +/- 20V). It won't run at 28V. - One needs to be careful as there may be different versions, checking is certainly to be recommended but this comment comes from versions 3, 4, and 5, of the Thunderbolt manual. The ThunderBolt comes with a 24V power supply regulator. A locally supplied +24VDC is required. Power consumption is 15 watts cold and 10 watts steady state. The connector is an AMP mate-n-loc (AMP part number 643228-1). The AMP mate-n-loc mating connectors are listed in the table below. An AMP hand tool (PN 90300-2) may be required.. regards Nigel GM8PZR ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Z3815A
Magnus, The Agilent Z3815A is a very nice unit, and fairly easy to get going. The main problem is software, which we had to specially write, although some versions of Ulrich's Z38XX work with it quite well. (The problem is subtle differences in the SCPI syntax). Yes, the backplane carries all the required signals except the serial comms. Use 2.54mm spaced header pins to connect. For power, use a little Veroboard with headers on. The DC supply connects to pins A54 to A58 (B) and A59 to A63 (A). Polarity is unimportant, and it operates from regulated 20 to 56V. A 24V 2A switch-mode plug pack will do the job. This supply is isolated from the rest of the unit. There are other outputs on the backplane, which I will leave you to find! They include 19.6608MHz, 4.096MHz and 1.544Mhz. The coaxial block consists of three independently buffered 10MHz sine outputs at +13dBm (B1 to B3). The GPS antenna (5V active) connects to A4. I've never had any success finding matching connectors at a sensible price, and so simply solder the antenna cable and 10MHz outputs to the back of the board. This connector is not soldered in, but simply held by its insert barbs. You can't prize it out as a unit, but I'm told that if you break up the plastic you can remove the inserts one at a time, although I've not tried it. The serial comms is wired with the wrong connector sense, so it's best to make a dedicated cable, or use a Null Modem cable with a DB9 M-M adaptor at one end. It doesn't talk unless spoken to, and uses 9600-N-8-1, SCPI protocol. If you have one of the earlier Z3815A units, you will find the superb HP E1938A 10MHz reference oscillator inside. There were manufacturing problems with these units, I understand, and later ones (like mine) have a Milliren 260 series 5MHz DOCXO (with excellent specs) on a daughter board made by Symmetricom. There is a full (unofficial) manual and software available on CD for the Z3815A - write to ksca...@bytecan.com.au. The manual lists all known commands, and also covers the Korean clone of the Z3815A, which is electrically and firmware different but externally identical. Software includes a monitor program with multiple windows and a rather cool retro and very realistic Nixie Clock. Regards, Murray Greenman -- Message: 4 Date: Thu, 10 Jun 2010 09:41:00 +0200 From: Magnus Danielson mag...@rubidium.dyndns.org Subject: [time-nuts] HP Z3815A hookup To: Discussion of precise time and frequency measurement time-nuts@febo.com Message-ID: 4c10970c.10...@rubidium.dyndns.org Content-Type: text/plain; charset=ISO-8859-1; format=flowed Hi! I just got a HP Z3815A but it seems like it is a bit of a challenge to hook it up. I see one large connector for some bus-structure, but don't know the pinning. There is also an 8 coax connector, where I suspect the antenna, 10 MHz, PPS and other generated frequencies pop out. The RS-232 on the front is obvious. I know there is a few SMBs inside, but it would be nice to get some practical hints from people playing with them before. Yes, the hockey-puck is there. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt not seeing satellites
Hi Steve, I don't know what the issue is, but my experience was very similar. My Tbolt is the same (or very similar) to yours and worked fine for a few years off and on. When Lady Heather became available, I took it out again. It worked great with the antenna indoors in my lab for about 4 hours, then data displayed by LH gradually dropped off to what you would see if the unit wasn't working. Since then I've tried again many times with the antenna in various locations, including full sky view with no results. No alarms except for the ones you would see in a normal start situation. Did the factory reset, etc. It has never seen a sat since. The antenna and cable are good. My primary receiver is a Z3801A, so I've had little incentive to delve into this problem (too many other pressing projects). -Dave - Original Message - From: Steve stev...@suddenlink.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, June 10, 2010 12:09:11 PM GMT -08:00 US/Canada Pacific Subject: [time-nuts] Thunderbolt not seeing satellites Hi all, I have used a Trimble Thunderbolt for several years as a source for accurate 10MHz signals for counters and signal generators. I have occasionally looked at the Thunderbolt with a laptop and Lady Heather, but have largely treated the Thunderbolt as a plug-and-play-and-forget-about-it device. Several weeks ago I acquired one of the fluke.l monitors and attached it to the Thunderbolt, placing the fluke.l in a location such that I see it every time I walk into my shop. To my dismay, after watching the fluke.l for a while, I discovered that my Thunderbolt rarely sees satellites. I then began more intense monitoring with Lady Heather, finding that the Thunderbolt will on rare occasions show one satellite as usable, most of the time none. Another Thunderbolt, purchased in May, 2008, when they were sold on this list, routinely see 4-8 satellites when connected to the same antenna. Input voltage to the poor performing unit is about 28VDC. I did the tboltmon.exe Factory Reset with no discernible difference in performance. It is the Thunderbolt model in the aluminum housing with the red and black Trimble Thunderbolt label on top. Any thoughts as to what's wrong with it? Steve -- Read The Patriot Post Vertitas vos Liberabit http://patriotpost.us/subscription/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Thunderbolt not seeing satellites
Hi all, I have used a Trimble Thunderbolt for several years as a source for accurate 10MHz signals for counters and signal generators. I have occasionally looked at the Thunderbolt with a laptop and Lady Heather, but have largely treated the Thunderbolt as a plug-and-play-and-forget-about-it device. Several weeks ago I acquired one of the fluke.l monitors and attached it to the Thunderbolt, placing the fluke.l in a location such that I see it every time I walk into my shop. To my dismay, after watching the fluke.l for a while, I discovered that my Thunderbolt rarely sees satellites. I then began more intense monitoring with Lady Heather, finding that the Thunderbolt will on rare occasions show one satellite as usable, most of the time none. Another Thunderbolt, purchased in May, 2008, when they were sold on this list, routinely see 4-8 satellites when connected to the same antenna. Input voltage to the poor performing unit is about 28VDC. I did the tboltmon.exe Factory Reset with no discernible difference in performance. It is the Thunderbolt model in the aluminum housing with the red and black Trimble Thunderbolt label on top. Any thoughts as to what's wrong with it? Steve -- Read The Patriot PostVertitas vos Liberabit http://patriotpost.us/subscription/ ___ time-nuts mailing 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] High reverse isolation amplifier
Hi Any idea what the phase noise floor is on them? Bob On Jun 10, 2010, at 2:25 PM, Corby Dawson wrote: I have purchased a few of the Z1B base kits from Clifton Labs, Jack Smith and am very impressed by them. I am using them as isolation amps in a DMTD unit. At 5Mhz the reverse isolation is -110db and at 10Mhz it's better than -100. Stringing two in series would be overkill but would give you even more isolation. (no idea how you could begin to measure the reverse isolation of the two in series!) see: http://www.cliftonlaboratories.com/z1_buffer_amp.htm Corby Dawson Try this Weight Loss Trick Simple weight loss secret to lose 12 pounds in 30 days http://thirdpartyoffers.juno.com/TGL3141/4c112e33d320051cd1m04duc ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt not seeing satellites
Hi I would certainly check the solder connections to the RF and power connectors on the PC board. Some of them apparently didn't get a real good solder job when they were new. Bob On Jun 10, 2010, at 3:09 PM, Steve wrote: Hi all, I have used a Trimble Thunderbolt for several years as a source for accurate 10MHz signals for counters and signal generators. I have occasionally looked at the Thunderbolt with a laptop and Lady Heather, but have largely treated the Thunderbolt as a plug-and-play-and-forget-about-it device. Several weeks ago I acquired one of the fluke.l monitors and attached it to the Thunderbolt, placing the fluke.l in a location such that I see it every time I walk into my shop. To my dismay, after watching the fluke.l for a while, I discovered that my Thunderbolt rarely sees satellites. I then began more intense monitoring with Lady Heather, finding that the Thunderbolt will on rare occasions show one satellite as usable, most of the time none. Another Thunderbolt, purchased in May, 2008, when they were sold on this list, routinely see 4-8 satellites when connected to the same antenna. Input voltage to the poor performing unit is about 28VDC. I did the tboltmon.exe Factory Reset with no discernible difference in performance. It is the Thunderbolt model in the aluminum housing with the red and black Trimble Thunderbolt label on top. Any thoughts as to what's wrong with it? Steve -- Read The Patriot PostVertitas vos Liberabit http://patriotpost.us/subscription/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Thunderbolt not seeing satellites
It may or may not tell you what's wrong but a quick check of the Thunderbolt would be to put a tee in series with the antenna and see if the unit is supplying +5 volts under load to the antenna.You have verified that the antenna works with a second unit so you can rule that out. Where you are getting some data from Lady Heather showing it picks up at least 1 satellite I suspect the +5 Vdc power supply that supplies the logic is functioning properly or you'd probably see no data. The +12 Vdc mainly supplies the oscillator so if that's working properly, the +12 is probably ok, It may well be a component in the receiver section on the Thunderbolt board. The Thunderbolt receiver board I looked at had a Macom AM50002 amplifier ( http://cs.utsource.net/goods_files/pdf/71/71500_MACOM_AM52.pdf ) located on the top side of the board directly behind the antenna connector. The bottom side of the board has D1, Q1, and R1 directly behind the 1PPS connector and they apparently supply the +5 to power the antenna. Those two areas would be likely suspects. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt not seeing satellites
In a message dated 10/06/2010 20:14:40 GMT Daylight Time, stev...@suddenlink.net writes: Input voltage to the poor performing unit is about 28VDC. I did the tboltmon.exe Factory Reset with no discernible difference in performance. It is the Thunderbolt model in the aluminum housing with the red and black Trimble Thunderbolt label on top. Presumably this is the version that contains a switch mode PSU to generate the 5, 12, and -12 volts needed by the T'bolt. Have you checked the outputs of that PSU? regards Nigel GM8PZR ___ time-nuts mailing 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] Reciprocal Counters
There will likely be one of these at the Electronics Flea Market in Cupertino, CA this Saturday. I saw it last month with a $20 price tag, but my guess is that if you can lift it it's yours. it's the one with the stack of neon blubs for each digit. (Somewhere I have one in a garage as well...) Leigh/WA5ZNU Hi You could always set up a Beckman EPUT meter to do period and get effectively the same sort of result. No solid state in them at all. Full of warm glowing stuff (some of it glowed yellow, some of it glowed purple). Bob ___ time-nuts mailing 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] Reciprocal Counters
Hi Yup, 10 neons in a column for readout of each decade. Lots of mercury vapor triodes in each decade. Even back 40 years ago the triodes weren't all that common. Today .. who knows. Bob On Jun 10, 2010, at 7:32 PM, Leigh L. Klotz, Jr. WA5ZNU wrote: There will likely be one of these at the Electronics Flea Market in Cupertino, CA this Saturday. I saw it last month with a $20 price tag, but my guess is that if you can lift it it's yours. it's the one with the stack of neon blubs for each digit. (Somewhere I have one in a garage as well...) Leigh/WA5ZNU Hi You could always set up a Beckman EPUT meter to do period and get effectively the same sort of result. No solid state in them at all. Full of warm glowing stuff (some of it glowed yellow, some of it glowed purple). Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt not seeing satellites
My understanding is that you have the older red box. Manual for the red box is there: http://www.ko4bb.com/Manuals/05%29_GPS_Timing/Trimble/Trimble_-_Thunderbolt/ ThunderBolt_Datasheet_%28red_box%29.pdf The power spec is 24V nominal, 18V min to 36V max Mine has been running off a small open frame linear 24V supply for several years. If it does not work at 28V, there must be something wrong with it. I do not recommend trying a voltage higher than 36V unless you have a couple Franklins to spare. My opinion is that it would be best to try and troubleshoot the problem first. A power supply problem should not be too hard to identify, knowing that internally, the Thunderbolt runs from +5V and +/- 12V. I do not have the detailed specs on these voltages, but the +12V drives the oven, so it should be stable, even though the nominal value is probably not too critical. The -12V only drives the RS-232, so it is probably not critical at all. The 5V drives a lot of logic and should probably be within 0.25V or better. I suspect the 5V drives the DAC that drives the EFC, but there must be another regulator/reference between the 5V and the DAC reference input. I believe TVB did some voltage sensitivity test at one point on the Group-buy TBs, but off-hand, I do not remember. Didier -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark Sims Sent: Thursday, June 10, 2010 5:33 PM To: time-nuts@febo.com Subject: [time-nuts] Thunderbolt not seeing satellites I'm not sure of the required power spec, but 28V may be too low. These were meant to run off a telco power bus (nominal 48V). I run mine at 40V (from a Tek PS503A mounted in a TM501 mainframe, unit connected across the + and - supply terminals, outputs set to +/- 20V). It won't run at 28V. Input voltage to the poor performing unit is about 28VDC. _ The New Busy is not the old busy. Search, chat and e-mail from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:W L:en-US:WM_HMP:042010_3 ___ time-nuts mailing 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] TPLL secret reveled
Where does the 1e-15 figure come from? Is that phase and are the units seconds or radians? Or is that relative frequency at the mixer, if so over what tau does it refer to? I'm curious how you measured or calculated the 1e-15 number. Saying very nearly zero doesn't mean much to me. In science we use numbers; often scientific notation. So in this case does nearly zero mean one microvolt? One nanovolt? One picovolt? Sorry if I'm dense here. /tvb - Original Message - From: WarrenS warrensjmail-...@yahoo.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, June 10, 2010 4:16 PM Subject: Re: [time-nuts] TPLL secret reveled Tom The ADC is measuring the EFC averaged voltage signal. I think all understand that the EFC controls the Frequency of the Ref OSC. This EFC voltage (freq) is what the external S/W uses to convert the two oscillator differences into ADEV. The Phase difference at the phase detector output is held to zero (within 1e-15 or so) by the gain of the AMP. The phase detector output looks like a summing junction, nothing is going to happen to make the point change from VERY nearly zero. So there is NO phase change, because phase is always at a constant 90 deg between the two oscillators. sorry I can not explain it better than that, I'm sure other can. ws *** Tom asked: Fact #1) the TPLL uses Freq not phase, Warren, can you please clarify. From what I can see it actually uses a Minicircuits phase detector, right? That suggests what is being observed is a phase difference between the DUT and the REF, not a frequency difference. That analog phase measurement is then filtered and amplified into a pre-calibrated EFC correction to the REF which over a short time reduces the phase difference as seen by the phase detector. The digital stream comes from an ADC is connected to the EFC. So what does it mean to say TPLL uses Freq not phase? It looks to me like it uses both. /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] TPLL secret reveled
Warren, can you please clarify. From what I can see it actually uses a Minicircuits phase detector, right? That suggests what is being observed is a phase difference between the DUT and the REF, not a frequency difference. That analog phase measurement is then filtered and amplified into a pre-calibrated EFC correction to the REF which over a short time reduces the phase difference as seen by the phase detector. The digital stream comes from an ADC is connected to the EFC. So what does it mean to say TPLL uses Freq not phase? It looks to me like it uses both. The VCO tuning voltage is proportional to frequency, as the VCO acts as an integrator in a type-2 PLL like this one. (Remember that the phase detector is on the other side of the VCO.) -- john, KE5FX ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt not seeing satellites
The TB has an error flag if there is no antenna connected (open) or if it is shorted. The tboltmon PC software reports these flags, and so does my GPSMon firmware in the fluke.l monitor. It is possible but unlikely that there would be something wrong with the bias circuit that would not be reported by the TB. Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Arthur Dent golgarfrinc...@yahoo.com Date: Thu, 10 Jun 2010 15:49:00 To: time-nuts@febo.com Subject: [time-nuts] Thunderbolt not seeing satellites It may or may not tell you what's wrong but a quick check of the Thunderbolt would be to put a tee in series with the antenna and see if the unit is supplying +5 volts under load to the antenna.You have verified that the antenna works with a second unit so you can rule that out. Where you are getting some data from Lady Heather showing it picks up at least 1 satellite I suspect the +5 Vdc power supply that supplies the logic is functioning properly or you'd probably see no data. The +12 Vdc mainly supplies the oscillator so if that's working properly, the +12 is probably ok, It may well be a component in the receiver section on the Thunderbolt board. The Thunderbolt receiver board I looked at had a Macom AM50002 amplifier ( http://cs.utsource.net/goods_files/pdf/71/71500_MACOM_AM52.pdf ) located on the top side of the board directly behind the antenna connector. The bottom side of the board has D1, Q1, and R1 directly behind the 1PPS connector and they apparently supply the +5 to power the antenna. Those two areas would be likely suspects. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt not seeing satellites
The voltages I measure are 11.8, -12.3 and 4.9VDC. Those measurements are with the unit operating and the power supplies under normal load. There is 4.7VDC on the feed to the antenna, that is with the coax attached to the Thunderbolt. Arthur's suggestion that something is amiss in the RF section seems probable. Thanks for the thoughts and ideas, anything else to consider? Steve On 6/10/2010 8:22 PM, Didier Juges wrote: The TB has an error flag if there is no antenna connected (open) or if it is shorted. The tboltmon PC software reports these flags, and so does my GPSMon firmware in the fluke.l monitor. It is possible but unlikely that there would be something wrong with the bias circuit that would not be reported by the TB. Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Arthur Dentgolgarfrinc...@yahoo.com Date: Thu, 10 Jun 2010 15:49:00 To:time-nuts@febo.com Subject: [time-nuts] Thunderbolt not seeing satellites It may or may not tell you what's wrong but a quick check of the Thunderbolt would be to put a tee in series with the antenna and see if the unit is supplying +5 volts under load to the antenna.You have verified that the antenna works with a second unit so you can rule that out. Where you are getting some data from Lady Heather showing it picks up at least 1 satellite I suspect the +5 Vdc power supply that supplies the logic is functioning properly or you'd probably see no data. The +12 Vdc mainly supplies the oscillator so if that's working properly, the +12 is probably ok, It may well be a component in the receiver section on the Thunderbolt board. The Thunderbolt receiver board I looked at had a Macom AM50002 amplifier ( http://cs.utsource.net/goods_files/pdf/71/71500_MACOM_AM52.pdf ) located on the top side of the board directly behind the antenna connector. The bottom side of the board has D1, Q1, and R1 directly behind the 1PPS connector and they apparently supply the +5 to power the antenna. Those two areas would be likely suspects. ___ time-nuts mailing 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. -- Read The Patriot PostVertitas vos Liberabit http://patriotpost.us/subscription/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt not seeing satellites
Hi I suspect that the unit puts out an ok 10 MHz signal. That would suggest that the +12 and likely the +5 supplies are ok. If the monitor software can talk to it, that's another indication that the +/-12 and +5 are fairly close to working. I think that a problem with the GPS front end / antenna connection is the most likely issue. Here's another one to consider though: How far off *is* the 10 MHz output? If the OCXO has gone way off frequency, the GPS may not be able to lock. It should be pretty simple to check with a counter and the second TBolt. Bob On Jun 10, 2010, at 8:22 PM, Didier Juges wrote: The TB has an error flag if there is no antenna connected (open) or if it is shorted. The tboltmon PC software reports these flags, and so does my GPSMon firmware in the fluke.l monitor. It is possible but unlikely that there would be something wrong with the bias circuit that would not be reported by the TB. Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Arthur Dent golgarfrinc...@yahoo.com Date: Thu, 10 Jun 2010 15:49:00 To: time-nuts@febo.com Subject: [time-nuts] Thunderbolt not seeing satellites It may or may not tell you what's wrong but a quick check of the Thunderbolt would be to put a tee in series with the antenna and see if the unit is supplying +5 volts under load to the antenna.You have verified that the antenna works with a second unit so you can rule that out. Where you are getting some data from Lady Heather showing it picks up at least 1 satellite I suspect the +5 Vdc power supply that supplies the logic is functioning properly or you'd probably see no data. The +12 Vdc mainly supplies the oscillator so if that's working properly, the +12 is probably ok, It may well be a component in the receiver section on the Thunderbolt board. The Thunderbolt receiver board I looked at had a Macom AM50002 amplifier ( http://cs.utsource.net/goods_files/pdf/71/71500_MACOM_AM52.pdf ) located on the top side of the board directly behind the antenna connector. The bottom side of the board has D1, Q1, and R1 directly behind the 1PPS connector and they apparently supply the +5 to power the antenna. Those two areas would be likely suspects. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Thunderbolt not seeing satellites
Hi Bob, I took a look at the 10MHz output. The unit had been unpowered on my bench for an hour or so. It took about 10 minutes to stabilize at 1.9Hz on the high side of 10MHz as measured on a GPS-referenced counter. Oscilloscope indicates a level of about +12dBm and a clean looking sine wave. So the OCXO would appear to be functional. Thanks for the suggestion. Anyone know of a source for board layout/schematics/parts list? Might be interesting to look at, although it is likely beyond my skill set to effect a repair :-\ Steve On 6/10/2010 9:59 PM, Bob Camp wrote: Hi I suspect that the unit puts out an ok 10 MHz signal. That would suggest that the +12 and likely the +5 supplies are ok. If the monitor software can talk to it, that's another indication that the +/-12 and +5 are fairly close to working. I think that a problem with the GPS front end / antenna connection is the most likely issue. Here's another one to consider though: How far off *is* the 10 MHz output? If the OCXO has gone way off frequency, the GPS may not be able to lock. It should be pretty simple to check with a counter and the second TBolt. Bob On Jun 10, 2010, at 8:22 PM, Didier Juges wrote: The TB has an error flag if there is no antenna connected (open) or if it is shorted. The tboltmon PC software reports these flags, and so does my GPSMon firmware in the fluke.l monitor. It is possible but unlikely that there would be something wrong with the bias circuit that would not be reported by the TB. Didier Sent from my BlackBerry Wireless thingy while I do other things... -Original Message- From: Arthur Dentgolgarfrinc...@yahoo.com Date: Thu, 10 Jun 2010 15:49:00 To:time-nuts@febo.com Subject: [time-nuts] Thunderbolt not seeing satellites It may or may not tell you what's wrong but a quick check of the Thunderbolt would be to put a tee in series with the antenna and see if the unit is supplying +5 volts under load to the antenna.You have verified that the antenna works with a second unit so you can rule that out. Where you are getting some data from Lady Heather showing it picks up at least 1 satellite I suspect the +5 Vdc power supply that supplies the logic is functioning properly or you'd probably see no data. The +12 Vdc mainly supplies the oscillator so if that's working properly, the +12 is probably ok, It may well be a component in the receiver section on the Thunderbolt board. The Thunderbolt receiver board I looked at had a Macom AM50002 amplifier ( http://cs.utsource.net/goods_files/pdf/71/71500_MACOM_AM52.pdf ) located on the top side of the board directly behind the antenna connector. The bottom side of the board has D1, Q1, and R1 directly behind the 1PPS connector and they apparently supply the +5 to power the antenna. Those two areas would be likely suspects. ___ time-nuts mailing 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. -- Read The Patriot PostVertitas vos Liberabit http://patriotpost.us/subscription/ ___ time-nuts mailing 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] TPLL secret reveled
Ulrich Bangert wrote: Jim, pardon if I correct you: The reciprocal counters were an intermediate thing between the counting only and the subclock interpolating ones. A reciprocal counter would notice when a frequency measurement would be too imprecise due to an arkward relationship between that gate time and the frequency to be measured. With only a few zero crossings within the gate time a reciprocal counter would use the frequency to be measured as the source for its gate time and measure the frequency of its reference with that. The result is then back computed to the frequency to be measured. This principle has nothing to do with sub clock interpolation. Nevertheless it is true that once that the reciprocal principle has been introduced it has been used in all following technologies. B Oh... ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
