[time-nuts] Measuring coax temperature coefficient with a TICC
That is the TAPR TICC small, low cost, open source, two channel time interval counter. It offers around 60 ps resolution / 100 ps jitter for $200. It's a rather nifty device... https://www.tapr.org/kits_ticc.html -- > Please forgive my ignorance but what is a TICC? ___ time-nuts mailing 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] Name of integral of timing residual
Jim Palfreyman writes: > Consider a plot of a timing residual vs time. Say a watch against a maser, > residual=watch-maser. We usually don't use the word residual for this. When you compare a watch with a maser, or any DUT time against REF time, you get a quantity like: phase difference, or sometimes just "phase", or time difference, time error, time interval, time interval error, etc. What residual usually refers to is if you post-process the raw time or frequency data in some way to better expose underlying structure. For example, if you remove a linear or quadratic fit from your phase data the resulting data set can be called phase residuals. This is done with free-running clocks because both frequency, and especially phase, diverge badly over time. So plotting residuals removes large systematic effects and exposes small effects of interest. > Now if I now plot the cumulative sum (think integral) of the residual, > that's going to give me an overall view of how the clock is performing over > time. A traditional phase plot of residuals is itself "an overall view of how the clock is performing over time". That's why even before we make ADEV plots we want to see the phase (actually, phase difference) plot and maybe also the frequency (usually, normalized frequency) plot. Both give an overall view of how the clock is performing, not to mention the ADEV plot which even further summarizes clock performance. A cumulative sum, an integral, of the timing residuals is a bit odd, but not wrong. This is the "area under the curve" of any residual phase plot. A traditional phase plot gives you a series of points on a line -- these tell you your clock error as a function of elapsed time. But plots are 2D, so your eye also senses the amount of area under the line -- this tells you not only how far off your clock is, but how long your clock has been how far off. The plot shows, and the eye recognizes both the line (how far) and the area (how far x how long). > (If it helps, think of PID controllers and how they work in the "I" part.) Yes, exactly. And the reason this is explicit in PID (or PIID) is that there is no human eye and no 2D plot. Therefore the PID algorithm has to manually compute the "area under the curve"; it has to calculate the cumulative sum as a scaler value. And it sounds like this single scaler value, as opposed to a rendered plot image, is what you're after. > Now if you look at *motion* of an object over time, and you integrate its > acceleration you get velocity, integrate again you get displacement. > Integrate again and you get "absement" and again you get "abcity" (I only > recently discovered these terms). Ok, thanks for that word of the day! Full list here: https://en.wikipedia.org/wiki/Absement#Higher_integrals > Does the integral of a timing residual have a name, and does the integral > of *that* have a name as well? Nope. But let's make one up in honor of your time spent doing Pulsar work. Some sources suggest absement is a portmanteau of absent and displacement. Ok, could be, but just as likely ab- is a fine Latin prefix on its own, meaning away, depart. Think of abnormal, abhor, absent, abdicate, aberrant. Or the German abfahren, to depart from. (Ah, I finally got to put my Latin and German to use; or is that abuse). https://en.wiktionary.org/wiki/ab- http://membean.com/wrotds/ab-away https://www.vocabulary.com/lists/135086 Anyway, in the world of space / distance: -4 abserk -3 abseleration -2 absity -1 absement 0 displacement +1 velocity +2 acceleration +3 jerk So how about for the world of time, we call integrated phase error: abtimer, or just abtime: -1 abtime (integrated phase error, cumulative sum of time error, etc.) units: s^2 0 time (phase, time error, phase difference, etc.) units: s +1 frequency (rate of phase change, etc.) units: /s, Hz +2 drift (linear frequency change) units: /s^2, Hz/s I can imagine cases where abtime would be useful, especially for closed loops. Units are seconds^2, or second*days, etc. For example, it may come in handy when I post plots of the new WWVB receiver, or characterizing a sloppy GPSDO timing receiver. /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] Measuring coax temperature coefficient with a TICC
> Please forgive my ignorance but what is a TICC? > Regards > John P Short answer: https://www.febo.com/pages/TICC/ https://www.tapr.org/kits_ticc.html Long answer: When working with precise time one of the very first instruments you'll want is a frequency counter. But when your clocks get accurate enough that your counter always reads 9.999 or 9.99 or 10.0 a different measurement approach is called for. This is where a phase meter or Time Interval Counter (TIC) is useful: instead of making a frequency measurement for a fixed duration (gate time), you can instead continuously monitor the slow and steady drift in phase (time) between two sources; over seconds, over hundreds of seconds, even over days. Programs like Stable32 or TimeLab can make phase, frequency, or stability plots from the data set. That's why a TIC can be used to measure coax temperature coefficient. A frequency counter can't do that. Most of us get our counters from eBay where the favorite TIC's are SR 620, hp 5335, hp 5370, hp 53132. But it has always been a challenge to make a modern, cheap, homebrew TIC that matches commercial instruments in performance. Over the years a number of time nuts have tried to make sub-nanosecond counters. The most recent time interval counter by John Ackermann, the "TICC", is a winner. See the links above for details. By using a recent off-the-shelf TDC (time to digital) chip from ti.com John avoided the complexity and analog calibration of earlier amateur designs. In order to allow arbitrary range of interval, he actually uses two TDC chips; one to precisely time the start pulse, and another to time the stop pulse. Moreover, John's "TICC" exposes the underlying start and stop channel timestamps so that the board not only acts like a simple start=A stop=B TIC, but can also be used as a dual-channel time-stamping counter (TSC). Unlike commercial counters, both the A and B inputs can collect data simultaneously and independently if you want. This avoids certain deadtime, collision and sampling issues that many commercial TIC's have. So it's a very nice design, and low cost, and open source. /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] Berkeley Nucleonics Phase Noise Testing system webinar
Thought this might be of interest --- I own couple BNC (Berkeley Nucleonics Corp) instruments, and get ads from them occasionally. Perhaps someone in the group might be interested, since we all are interested in measuring and limiting phase noise in our sources. Obviously, they are promoting their technology, but they might have something new and interesting to offer. Take advantage of this opportunity to register for BNC's Evolution Series webinar focusing on our highest performance Phase Noise Testing system yet, the model 7330. This webinar being held on Wednesday, May 17th at 10am PST offers a glimpse into the future of phase noise testing technology and its direction. Be ahead of the curve with RF Instrumentation for the modern engineer. A complete turnkey PC-Driven solution providing measurements from 5MHz to 33GHz with offsets from .01 Hz to 100 MHz Users enjoy the portability, durability, and reliability of an "interface-less" PC-driven package designed with the user in mind. Unrivaled and powerful performance that is extremely easy to use, with measurements performed with a simple click of a button. Advanced measurement tools provided are: Pulsed measurements, Amplitude Measurements, Ultra-low noise internal references or external references with a -185dBc/Hz noise floor, Absolute and additive measurements together. Register using this Link Come see the best solution for VCO characterization, ATE requirements, Amplitude measurements, and Pulsed capabilities! ___ time-nuts mailing 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] Measuring coax temperature coefficient with a TICC
Please forgive my ignorance but what is a TICC? Regards John P ___ time-nuts mailing 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] Name of integral of timing residual
Hi On a normal GPSDO holdover spec, you are concerned with the maximum time error over a specified period. Generally it’s going to be a 24 hour holdover, but it can be longer or shorter depending on the application. The good old CDMA spec got out into the 10 to 11 us range at 24 hours. Various OEM’s padded the number to give a bit of wiggle room. The spec typically referred to it as “maximum allowed error”. While a straight(ish) line from zero to max is a typical example, they really didn’t care if it was a second, third, or fourth order wiggle bouncing go either side of zero over the period. Figure 8 in the application note is a pretty good example of this. I *think* what is being asked for is the integral of figure 8 ….which is indeed not something I’ve ever seen named. Bob > On Apr 20, 2017, at 8:26 AM, Tim Shoppa wrote: > > I looked at AN1279 and other HP Smartclock documents that were written for > the telco holdover specs, and they always put a zero axis on the frequency > offset, but I was surprised that for example fig A4 of AN1279 seems to be > suppressing the zero axis for the time error. So they seemed to be > unconcerned with the integral you speak of. > > Tim N3QE > > > On Thu, Apr 20, 2017 at 1:17 AM, Jim Palfreyman wrote: > >> Folks, >> >> I'm after the formal name of something (if it exists), and this group, if >> any, should know. >> >> Consider a plot of a timing residual vs time. Say a watch against a maser, >> residual=watch-maser. >> >> Now if I now plot the cumulative sum (think integral) of the residual, >> that's going to give me an overall view of how the clock is performing over >> time. (If it helps, think of PID controllers and how they work in the "I" >> part.) >> >> Now if you look at *motion* of an object over time, and you integrate its >> acceleration you get velocity, integrate again you get displacement. >> Integrate again and you get "absement" and again you get "abcity" (I only >> recently discovered these terms). >> >> Does the integral of a timing residual have a name, and does the integral >> of *that* have a name as well? >> >> Any thoughts? >> >> >> Jim Palfreyman >> ___ >> time-nuts mailing 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] Name of integral of timing residual
I looked at AN1279 and other HP Smartclock documents that were written for the telco holdover specs, and they always put a zero axis on the frequency offset, but I was surprised that for example fig A4 of AN1279 seems to be suppressing the zero axis for the time error. So they seemed to be unconcerned with the integral you speak of. Tim N3QE On Thu, Apr 20, 2017 at 1:17 AM, Jim Palfreyman wrote: > Folks, > > I'm after the formal name of something (if it exists), and this group, if > any, should know. > > Consider a plot of a timing residual vs time. Say a watch against a maser, > residual=watch-maser. > > Now if I now plot the cumulative sum (think integral) of the residual, > that's going to give me an overall view of how the clock is performing over > time. (If it helps, think of PID controllers and how they work in the "I" > part.) > > Now if you look at *motion* of an object over time, and you integrate its > acceleration you get velocity, integrate again you get displacement. > Integrate again and you get "absement" and again you get "abcity" (I only > recently discovered these terms). > > Does the integral of a timing residual have a name, and does the integral > of *that* have a name as well? > > Any thoughts? > > > Jim Palfreyman > ___ > time-nuts mailing 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] Name of integral of timing residual
Hi Hi I think your “quest” to find the terms as they relate to motion is a pretty good example of just how unusual these terms are. Once you go past displacement, they are hardly common vocabulary. My guess is that nobody has ever come up with terms in the time domain that have made it into the common vocabulary describing this stuff. Bob > On Apr 20, 2017, at 1:17 AM, Jim Palfreyman wrote: > > Folks, > > I'm after the formal name of something (if it exists), and this group, if > any, should know. > > Consider a plot of a timing residual vs time. Say a watch against a maser, > residual=watch-maser. > > Now if I now plot the cumulative sum (think integral) of the residual, > that's going to give me an overall view of how the clock is performing over > time. (If it helps, think of PID controllers and how they work in the "I" > part.) > > Now if you look at *motion* of an object over time, and you integrate its > acceleration you get velocity, integrate again you get displacement. > Integrate again and you get "absement" and again you get "abcity" (I only > recently discovered these terms). > > Does the integral of a timing residual have a name, and does the integral > of *that* have a name as well? > > Any thoughts? > > > Jim Palfreyman > ___ > time-nuts mailing 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] Name of integral of timing residual
I think that should be "absity" (s not c) Dave -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Jim Palfreyman Sent: 20 April 2017 06:18 To: Discussion of precise time and frequency measurement Subject: [time-nuts] Name of integral of timing residual > Now if you look at *motion* of an object over time, and you integrate its > acceleration you get velocity, integrate again you get displacement. > Integrate again and you get "absement" and again you get "abcity" (I only > recently discovered these terms). ___ time-nuts mailing 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] Name of integral of timing residual
Hi, On 04/20/2017 07:17 AM, Jim Palfreyman wrote: Folks, I'm after the formal name of something (if it exists), and this group, if any, should know. Consider a plot of a timing residual vs time. Say a watch against a maser, residual=watch-maser. Now if I now plot the cumulative sum (think integral) of the residual, that's going to give me an overall view of how the clock is performing over time. (If it helps, think of PID controllers and how they work in the "I" part.) Now if you look at *motion* of an object over time, and you integrate its acceleration you get velocity, integrate again you get displacement. Integrate again and you get "absement" and again you get "abcity" (I only recently discovered these terms). Does the integral of a timing residual have a name, and does the integral of *that* have a name as well? Any thoughts? Wither it is timing residuals (time error (TE) or time interval error (TIE) ) or time itself does not change the core of it being integrated time. I have never heard of any definition for is, as we have for phase, frequency and linear drift. When considering similar problems with charge and current you end up with As (or Ah) which is a measure of energy (assuming a voltage), often referred to as capacity, but it doesn't really help. In this case, integrated time error is what I would use. It is not as catchy, but it is correct at least. 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.
