Re: [time-nuts] ADEV slopes and measurement mode

Thanks! I think it will require more than one reading.. :) Ole On Thu, Apr 19, 2018 at 12:08 AM, Magnus Danielson < mag...@rubidium.dyndns.org> wrote: > Hi Ole Petter, > > On 04/16/2018 12:12 PM, Ole Petter Ronningen wrote: > > Hi, All > > > > This will be a bit long, and I apologize for it.

Re: [time-nuts] ADEV slopes and measurement mode

Hi Ole Petter, On 04/16/2018 12:12 PM, Ole Petter Ronningen wrote: > Hi, All > > This will be a bit long, and I apologize for it. Perhaps someone else also > struggle with the same. > > One of the properties of the familiar ADEV-plots are the slopes - and how > the slope identify the dominant

Re: [time-nuts] ADEV dead time w/ HP 53131A & TimeLab

Hi David, On 04/09/2018 03:29 AM, David Burnett wrote: > Hi time-nuts, > > I'm doing oscillator-related research for my PhD and found this list > recently. It's been a great resource in trying to refine my freq > measurement setup and in starting to understand what's really going on > inside my

Re: [time-nuts] ADEV dead time w/ HP 53131A & TimeLab

Dave, > My research concerns oscillator drift on time scales of ~1ms to ~10s, so > I'm guessing the 53131A with its 5-130ms of dead time isn't suitable for > what I'm trying to measure. True. Try a fancy TIA (time interval analyzer) or MDA (modulation domain analyzer) instead. Or consider a

Re: [time-nuts] ADEV dead time w/ HP 53131A & TimeLab

Hi The basic fact is that oscillators drift on *all* time scales. How much they drift depends on the type of oscillator. A free running VCO based on a PCB resonator will drift differently than a bare crystal oscillator. An OCXO will have different drift characteristics than a bare oscillator.

Re: [time-nuts] ADEV data for mechanical clocks

> Does anybody have any ADEV data for mechanical clocks? (I didn't find any by > google, but there was a lot of noise so maybe I missed something.) Hal, It's often buried in out-of-print horological books or magazines / journals / articles that google may or may not index. I have some ADEV

Re: [time-nuts] ADEV data for mechanical clocks

On Tue, 06 Mar 2018 21:10:00 -0800 Hal Murray wrote: > Does anybody have any ADEV data for mechanical clocks? (I didn't find any by > google, but there was a lot of noise so maybe I missed something.) How about Tom's Powers of Ten?

Re: [time-nuts] ADEV query Timelab and TICC

econd.com>, Discussion of precise time and frequency measurement <time-nuts@febo.com> Cc: hmur...@megapathdsl.net Subject: Re: [time-nuts] ADEV query Timelab and TICC t...@leapsecond.com said: > The TAPR dividers tend not to have "this problem" because they output at > w

Re: [time-nuts] ADEV query Timelab and TICC

t...@leapsecond.com said: > The TAPR dividers tend not to have "this problem" because they output at > wimpy TTL/CMOS levels. Modern CMOS drivers have fast rise times. As long as the rise time is short relative to the cable length, it gets doubled if the end of the cable is an open circuit.

Re: [time-nuts] ADEV query Timelab and TICC

.@febo.com A "Discussion of precise time and frequency measurement" time-nuts@febo.com Cc Data Mon, 20 Mar 2017 09:48:24 -0700 Oggetto Re: [time-nuts] ADEV query Timelab and TICC Luciano, This should not happen with the hp 5065A or 5061B frequency standards. I'm glad you worke

Re: [time-nuts] ADEV query Timelab and TICc

ar 2017 22:09:57 -0700 From: Orin Eman <orin.e...@gmail.com> To: Tom Van Baak <t...@leapsecond.com>, Discussion of precise time and frequency measurement <time-nuts@febo.com> Subject: Re: [time-nuts] ADEV query Timelab and TICC Message-ID:

Re: [time-nuts] ADEV query Timelab and TICC

e-nuts@febo.com> Sent: Monday, March 20, 2017 12:56 AM Subject: Re: [time-nuts] ADEV query Timelab and TICC > > All, > the similar problem I have verified using the HP5065A and HP5061B 1PPS > output, the dividers are pratically unusable for ADEV measurements. The > 5/10MH

Re: [time-nuts] ADEV query Timelab and TICC

s The HP53132A. > Luciano > www.timeok.it > > > Da "time-nuts" time-nuts-boun...@febo.com >A "Discussion of precise time and frequency measurement" >time-nuts@febo.com > Cc > Data Sun, 19 Mar 2017 20:03:29 -0700 > Oggetto Re: [time-nuts] ADEV qu

Re: [time-nuts] ADEV query Timelab and TICC

using other TIC as The HP53132A. Luciano www.timeok.it Da "time-nuts" time-nuts-boun...@febo.com A "Discussion of precise time and frequency measurement" time-nuts@febo.com Cc Data Sun, 19 Mar 2017 20:03:29 -0700 Oggetto Re: [time-nuts] ADEV query Timelab

Re: [time-nuts] ADEV query Timelab and TICC

The LTE-Lite User Manual (version 1.3) says: 2.3.7 1 PPS Module outputs The LTE-Lite SMT Module provides GPS raw 1 PPS CMOS pulse on pin 15 with sawtooth present, and a clean TCXO-generated, sawtooth-removed, UTC(GPS) phase-locked 1PPS output on pin 4. It is the pin 4 output that connects to the

Re: [time-nuts] ADEV query Timelab and TICC

Many thanks for the replies on this, what was initially intended as a quick "Hello World" test seems to have become far more interesting:-) I'll forward my results to Tom as requested and see where we go from there. Nigel GM8PZR ___ time-nuts

Re: [time-nuts] ADEV query Timelab and TICC

On Sun, Mar 19, 2017 at 8:03 PM, Tom Van Baak wrote: > > Thanks for the raw data. It's very nice (2 hours 16 minutes = 8219 > points). Everything looks fine with the exception of 8 glitches. These are > sometimes obvious jumps in phase, which cause massive spikes in

Re: [time-nuts] ADEV query Timelab and TICC

Hi Orin, More info... If you try to manually remove the 25 ns glitches you get a data set that looks much better. Attached are the ADEV plots for (1) your raw data and (2) your data minus those 8 glitches. You can see the dramatic difference that just 8 points make. Blue is raw data, red is

Re: [time-nuts] ADEV query Timelab and TICC

t;t...@leapsecond.com> To: Discussion of precise time and frequency measurement <time-nuts@febo.com> Sent: Sunday, March 19, 2017 10:04 PM Subject: Re: [time-nuts] ADEV query Timelab and TICC > I have sent a couple of files to Tom.  They were taken simultaneously from > an L

Re: [time-nuts] ADEV query Timelab and TICC

> I have sent a couple of files to Tom. They were taken simultaneously from > an LTE Lite - one from the PPS and one from a PicDiv dividing the 10MHz to > 1Hz. The glitches were on the PPS trace, but not on the PicDiv trace, so > I'm fairly confident the TICC was working correctly. > > Orin.

Re: [time-nuts] ADEV query Timelab and TICC

t; Of Tom McDermott > Sent: Sunday, March 19, 2017 15:00 > To: Discussion of precise time and frequency measurement > Cc: gandal...@aol.com > Subject: Re: [time-nuts] ADEV query Timelab and TICC > > I had this happen this morning. (Running Windows 10). Had 7 > hours of good >

Re: [time-nuts] ADEV query Timelab and TICC

I saw a similar higher-than-expected ADEV from another user who was measuring GPSDO PPS vs. 10 MHz from the same GPSDO.  Using a T2-Mini  from the 10 MHz yields the expected results. I suspect that the GPSDO PPS in that unit is derived from GPS PPS rather than the OCXO, and thus is noisier in

Re: [time-nuts] ADEV query Timelab and TICC

On Sun, Mar 19, 2017 at 3:00 PM, Tom Van Baak wrote: > > I've seen similar with my TICC when observing a PPS - can't remember > > whether the PPS was from the Thunderbolt or LTE Lite. > > > > There was a distinct glitch on the frequency plot when it happened and it > > was

Re: [time-nuts] ADEV query Timelab and TICC

I had this happen this morning. (Running Windows 10). Had 7 hours of good data running overnight, (good ADEV, Freq Diff plots). Then There was a big pop' in the frequency difference trace. ADEV messed up suddenly. It happened coincident with starting up Microsoft Edge (which had not been run

Re: [time-nuts] ADEV query Timelab and TICC

> I've seen similar with my TICC when observing a PPS - can't remember > whether the PPS was from the Thunderbolt or LTE Lite. > > There was a distinct glitch on the frequency plot when it happened and it > was pretty easy in timelab to expand the trace around the glitch to take a > better look.

Re: [time-nuts] ADEV query Timelab and TICC

Hi It’s a pretty good bet that the “upper” trace has a noise pop in it. One of the wonderful things about ADEV is that a single noise event can impact the whole curve. That is a bit non-intuitive. It is indeed how the math works and how the testing comes out in the real world. Bob > On Mar

Re: [time-nuts] ADEV query Timelab and TICC

I've seen similar with my TICC when observing a PPS - can't remember whether the PPS was from the Thunderbolt or LTE Lite. There was a distinct glitch on the frequency plot when it happened and it was pretty easy in timelab to expand the trace around the glitch to take a better look. I did not

Re: [time-nuts] ADEV query Timelab and TICC

> I'm probably missing something obvious but don't understand what's > happened here so any suggestions would be welcome. Hi Nigel, Your setup sounds fine. Off-list, send me the TIM files and I'll see what happened. I know we all love ADEV but in general always look at the phase, phase

Re: [time-nuts] ADEV and fractional frequency

On Thu, 14 Apr 2016 07:33:11 -0700 Jeremy Nichols wrote: > Correct, Attila. I've been trying to find two separate definitions when > it seems they are the same thing. It also shows my age that I don't > automatically check Wikipedia. Well.. The formula there appears at a lot

Re: [time-nuts] ADEV and fractional frequency

Hi, Well, there is two different ways to evaluate ADEV, but the 5360 variant would be the non-overlapping Allan Deviation for sure. Cheers, Magnus On 04/14/2016 04:33 PM, Jeremy Nichols wrote: Correct, Attila. I've been trying to find two separate definitions when it seems they are the same

Re: [time-nuts] ADEV and fractional frequency

Correct, Attila. I've been trying to find two separate definitions when it seems they are the same thing. It also shows my age that I don't automatically check Wikipedia. Jeremy On 4/14/2016 3:18 AM, Attila Kinali wrote: Hoi Jeremy, On Wed, 13 Apr 2016 16:16:02 -0700 Jeremy Nichols

Re: [time-nuts] ADEV measurement question

Tom, thanks for sharing this! This was exactly what I was looking for. Regards, Matthias Am 23.08.2015 um 19:19 schrieb Tom Van Baak: To learn more, I think the best way would be to put the counter into its fast binary mode and acquire 1k time interval samples per second. That would give me

Re: [time-nuts] ADEV measurement question

To learn more, I think the best way would be to put the counter into its fast binary mode and acquire 1k time interval samples per second. That would give me loads of data to play with and it would be easy to try out how different averaging schemes affect the result. Matthias, See:

Re: [time-nuts] ADEV measurement question

Matthias, On 08/20/2015 09:55 PM, Matthias Jelen wrote: Dear John Magnus, thank you very much for your detailed explanation. I realize that the averaging topic is much more complex than I thought - it certainly gives me something to think about :-) I never thought in terms of noise bandwith

Re: [time-nuts] ADEV measurement question

Hi Next layer to this onion is that the low(er) frequency signals out of the mixer have slow(er) edges. There has been a lot of discussion on the list in the past about Dual Mixer Time Difference (DMTD) setups. The fast answer is in a paper by a gentleman by the name of Collins. on how to do

Re: [time-nuts] ADEV measurement question

Dear John Magnus, thank you very much for your detailed explanation. I realize that the averaging topic is much more complex than I thought - it certainly gives me something to think about :-) I never thought in terms of noise bandwith in this application, thanks for putting me on this

Re: [time-nuts] ADEV measurement question

Dear Mathias, On 08/19/2015 06:40 PM, Matthias Jelen wrote: Hello, I´ve got a question concerning ADEV-measurements. I´m measuring the 15 MHz output of a KS-24361 with my SR-620 with it´s internal (Wenzel) OCXO using Timelab. For the first shot I used the counters frequency mode with 1s

Re: [time-nuts] ADEV measurement question

I think the simplest way to explain the evils of TI averaging is that white noise doesn't alias in a conventional sense. If a value is perfectly random, then it doesn't matter how you sample it. Your sampling bandwidth -- and nothing else -- determines how much energy you get. You can

Re: [time-nuts] ADEV with very short Tau

-nuts@febo.com Envoyé: Mercredi 29 Avril 2015 22:04:14 Objet: Re: [time-nuts] ADEV with very short Tau Claude wrote: I know how to measure ADEV with frequency method (using a 53131A counter) or time difference method (using 1 PPS of a GPSDO for example) but I would like to measure ADEV in the sub

Re: [time-nuts] ADEV with very short Tau

Hi The cheap / simple approach for ADEV is a single or dual mixer setup. Mix the signal(s) down to an audio frequency and measure those. Mix down frequencies like 10 KHz will let you measure some pretty short Tau’s. If you want a purchased single box solution, then something like a TimePod

Re: [time-nuts] ADEV with very short Tau

Claude what is the simplest method to measure sub second ADEV? The answer depends on many unstated things. Among them is your definition of simple, the Frequency of the DUT, the noise floor, your budget and your available time.. After budget and frequency, the next most important thing is the

Re: [time-nuts] ADEV with very short Tau

Claude wrote: I know how to measure ADEV with frequency method (using a 53131A counter) or time difference method (using 1 PPS of a GPSDO for example) but I would like to measure ADEV in the sub-second domain (from 0.1s to 1s for example). Do I need a Time Interval Analyzer, if so, an HP

Re: [time-nuts] ADEV noise floor vs counter gate time

downloaded NI-VISA and got that working I probably don't need to download tek-VISA. Best Regards, James -Original Message- From: Bill Byrom t...@radio.sent.com To: time-nuts time-nuts@febo.com Sent: Sun, 22 Mar 2015 20:28 Subject: Re: [time-nuts] ADEV noise floor vs counter gate time

Re: [time-nuts] ADEV noise floor vs counter gate time

the results. James -Original Message- From: Bill Byrom t...@radio.sent.com To: time-nuts time-nuts@febo.com Sent: Sun, 22 Mar 2015 2:27 Subject: Re: [time-nuts] ADEV noise floor vs counter gate time Hi, James. I'm a Tektronix RF Application Engineer in Dallas and thought I

Re: [time-nuts] ADEV noise floor vs counter gate time

-Original Message- From: Bill Byrom t...@radio.sent.com To: time-nuts time-nuts@febo.com Sent: Sun, 22 Mar 2015 2:27 Subject: Re: [time-nuts] ADEV noise floor vs counter gate time Hi, James. I'm a Tektronix RF Application Engineer in Dallas and thought I would

Re: [time-nuts] ADEV noise floor vs counter gate time

To: jpbridge jpbri...@aol.com CC: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wed, 18 Mar 2015 15:22 Subject: Re: [time-nuts] ADEV noise floor vs counter gate time The counter always has a 1 count uncertainty in the timebase measurement, which is a 2e

Re: [time-nuts] ADEV noise floor vs counter gate time

. James -Original Message- From: Dave Martindale dave.martind...@gmail.com To: jpbridge jpbri...@aol.com; time-nuts time-nuts@febo.com Sent: Wed, 18 Mar 2015 1:26 Subject: Re: [time-nuts] ADEV noise floor vs counter gate time I believe I see the pattern. As you figured out

Re: [time-nuts] ADEV noise floor vs counter gate time

Sent: Wed, 18 Mar 2015 1:26 Subject: Re: [time-nuts] ADEV noise floor vs counter gate time I believe I see the pattern. As you figured out, you wouldn't expect a single period to be a multiple of 20 ns; you expect the length of (about) 90 periods to be an integer multiple of 50 ns, since that's

Re: [time-nuts] ADEV noise floor vs counter gate time

: Dave Martindale dave.martind...@gmail.com To: jpbridge jpbri...@aol.com; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tue, 17 Mar 2015 0:27 Subject: Re: [time-nuts] ADEV noise floor vs counter gate time How is the counter configured? Are you reading period

Re: [time-nuts] ADEV noise floor vs counter gate time

To: jpbridge jpbri...@aol.com CC: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wed, 18 Mar 2015 15:22 Subject: Re: [time-nuts] ADEV noise floor vs counter gate time The counter always has a 1 count uncertainty in the timebase measurement, which is a 2e-8 error

Re: [time-nuts] ADEV noise floor vs counter gate time

How is the counter configured? Are you reading period or frequency? Are you in E? (Every Result) mode, or C? (Continuous Result) mode? The former should give you continuous but independent measurements, while the latter gives heavily overlapped measurements. (For example, with a 100 second

Re: [time-nuts] ADEV noise floor vs counter gate time

I've worked out how to program it). James -Original Message- From: Dave Martindale dave.martind...@gmail.com To: jpbridge jpbri...@aol.com; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tue, 17 Mar 2015 0:27 Subject: Re: [time-nuts] ADEV noise floor vs

Re: [time-nuts] ADEV from phase or frequency measurement

Even if the -3dB were an issue, I'd have much more faith in a clear, passive resistor network than in a complex amplifier with all it's unknown non linear characteristics, temperature dependent time delays, noise sources, etc., etc. This simple home made network is a useful, manageable gadget.

Re: [time-nuts] ADEV from phase or frequency measurement

Hi I’ve played with both the 6 db loss resistive splitters and the transformer based 3 db loss splitters. They both seem to be fine for splitting precision 10 MHz signals. For a while I avoided the transformer based parts, but not for any reason I could prove. Bob On Mar 10, 2014, at 7:41

Re: [time-nuts] ADEV from phase or frequency measurement

On 04/03/14 01:05, Volker Esper wrote: Am 03.03.2014 23:04, schrieb Magnus Danielson: Volker, On 03/03/14 00:50, Volker Esper wrote: Sorry for the time delay... TIC: SR620 with Z3805 as external reference; signal source Nortel/Trimble GPSTM (GPSDO) 10MHz output Enclosed two plots (SW:

Re: [time-nuts] ADEV from phase or frequency measurement

Am 09.03.2014 19:46, schrieb Magnus Danielson: On 04/03/14 01:05, Volker Esper wrote: Am 03.03.2014 23:04, schrieb Magnus Danielson: Volker, On 03/03/14 00:50, Volker Esper wrote: Sorry for the time delay... TIC: SR620 with Z3805 as external reference; signal source Nortel/Trimble GPSTM

Re: [time-nuts] ADEV from phase or frequency measurement

On 09/03/14 22:36, Volker Esper wrote: Am 09.03.2014 19:46, schrieb Magnus Danielson: On 04/03/14 01:05, Volker Esper wrote: Am 03.03.2014 23:04, schrieb Magnus Danielson: Volker, On 03/03/14 00:50, Volker Esper wrote: Sorry for the time delay... TIC: SR620 with Z3805 as external

Re: [time-nuts] ADEV from phase or frequency measurement

Hi Do you routinely do arc welding while waiting for an ADEV plot to finish :)… (I drink beer, but not everybody is into that …) You might consider trying a passive splitter on one of the outputs of the GPSDO. There aren’t many ways they will mess up a signal other than by dropping it’s

Re: [time-nuts] ADEV from phase or frequency measurement

Bob, I sometimes indeed do arc welding, as well as forging... But that's another story. When waiting for an ADEV measurement I sit still, trying not to move a millimeter. Seriously, I try to avoid any rf noise, e.g. ham radio, any airflow, any temperature change. I log supply voltages and check,

Re: [time-nuts] ADEV from phase or frequency measurement

Hi So far, I have not found the 3db lost in a a passive splitter to be a problem with anything I have played with. With proper termination , they seem to be a good thing to use. Bob On Mar 9, 2014, at 7:55 PM, Volker Esper ail...@t-online.de wrote: Bob, I sometimes indeed do arc welding,

Re: [time-nuts] ADEV from phase or frequency measurement

Volker, On 03/03/14 00:50, Volker Esper wrote: Sorry for the time delay... TIC: SR620 with Z3805 as external reference; signal source Nortel/Trimble GPSTM (GPSDO) 10MHz output Enclosed two plots (SW: Plotter): - one is sigma(tau) calculated from phase samples (SR620 TIME mode), - the other

Re: [time-nuts] ADEV from phase or frequency measurement

Hi Volker, Either phase or frequency raw data can be used to generate an ADEV plot, but you have to use different methods depending on the data type. See the two formulas for Allan Variance in: http://www.wriley.com/paper2ht.htm Usually we use the x form of the formula, where x is an array of

Re: [time-nuts] ADEV from phase or frequency measurement

Thank you, Tom, so far. Yes, I know that I have to use different formulas, but - of course - I didn't calculate the ADEV curves myself, I let some software do the job, namely Ulrich's Plotter and TimeLab as well. Plotter has a menu item, where you have to check if you deal with phase or frequency

Re: [time-nuts] ADEV from phase or frequency measurement

Here is python code for the most common deviations https://github.com/aewallin/allantools/blob/master/allantools/allantools.py each statistic (ADEV, MDEV, TDEV, and so on) has two functions. one takes fractional frequency data, the other phase data. frequency2phase() and phase2freqeuncy() show

Re: [time-nuts] ADEV from phase or frequency measurement

Volker, On 01/03/14 12:15, Volker Esper wrote: Hello dear fellow time-nuts, I stumbled over a question that may sound stupid to you: Is the usual ADEV plot the result of a phase or a frequency measurement? I get totally different results when comparing a phase and a frequency measurement of

Re: [time-nuts] ADEV from phase or frequency measurement

On 01/03/14 13:25, Volker Esper wrote: Thank you, Tom, so far. Yes, I know that I have to use different formulas, but - of course - I didn't calculate the ADEV curves myself, I let some software do the job, namely Ulrich's Plotter and TimeLab as well. Plotter has a menu item, where you have to

Re: [time-nuts] ADEV from phase or frequency measurement

This is because usually a counter that has the time interval feature behaves better in time interval mode. As already pointed out here, use always the time interval mode to take samples for the Allan deviation. In frequency mode the counter uses average or various tricks to smooth readings, so

Re: [time-nuts] ADEV computed, now what?

Bob wrote: here's the result for 1PPS vs 10MHz for my GPSDO, as measured by a 5334B clocked by the same 10MHz.I don't know how to read these, but 6,3,1,6,3,1 etc. doesn't look normal. The adev results you obtained look very much like the adev results reported by Lady Heather, very

Re: [time-nuts] ADEV computed, now what?

time-nuts@febo.com Sent: Wednesday, February 5, 2014 5:47 AM Subject: Re: [time-nuts] ADEV computed, now what? Bob wrote: here's the result for 1PPS vs 10MHz for my GPSDO, as measured by a 5334B clocked by the same 10MHz.    I don't know how to read these, but 6,3,1,6,3,1 etc. doesn't look

Re: [time-nuts] ADEV computed, now what?

Hi What you have measured is the trigger error of your 5334. Since the 10 MHz and the pps are from the same source, all that’s left is trigger. Bob On Feb 4, 2014, at 9:45 PM, Bob Stewart b...@evoria.net wrote: I think I have the unwrapping and scaling sorted out, so here's the result for

Re: [time-nuts] ADEV ScaleFactor correction

On 16/01/14 07:54, WarrenS wrote: ADEV is a great tool for measuring random noise but not so good for systematic errors like ageing drift. I have seen on the better oscillator's that the typical ADEV rise with time is often the effect of changing temperature and/or ageing drift. I did an

Re: [time-nuts] ADEV ScaleFactor correction

The 1.4 scale factor correction worked Nice confirmation. The actual number is sqrt(2). Look at the definition of ADEV (http://tf.nist.gov/images/adevfreq.gif) to see why. Note sqrt(2) = 1.414 and 1/sqrt(7) is 0.707. The rule-of-thumb is that ADEV(tau 1 day) is 0.707 the daily drift rate;

Re: [time-nuts] ADEV ScaleFactor correction

1/sqrt(7) = 0.37796... sqrt(2)/2 = 0.707... -Chuck Harris Tom Van Baak wrote: The 1.4 scale factor correction worked Nice confirmation. The actual number is sqrt(2). Look at the definition of ADEV (http://tf.nist.gov/images/adevfreq.gif) to see why. Note sqrt(2) = 1.414 and 1/sqrt(7) is

Re: [time-nuts] ADEV drop

On 08/12/2012 05:02 AM, WarrenS wrote: The basic problem is that one can not meet Allan's requirement of the integral of the instantaneous frequencies over tau0 time and Nyquist-Shannon sampling theorem requirement if taking just one raw phase sample per displayed ADEV tau0. The two

Re: [time-nuts] ADEV drop

The basic problem is that one can not meet Allan's requirement of the integral of the instantaneous frequencies over tau0 time and Nyquist-Shannon sampling theorem requirement if taking just one raw phase sample per displayed ADEV tau0. The two requirements are then mutually exclusive. This is

Re: [time-nuts] ADEV noise bandwidth (was LPRO Rubidium Performance)

On 02/13/2012 02:19 AM, John Miles wrote: The ADEV difference of about 6 db at 1ms tau can be explained by the fact that if I apply a 500 Hz LP filter to my 9600 sps raw data, the same filter used on the 5120A's 1K sps data, then even our 1ms ADEV answers become very close. I have found that

Re: [time-nuts] ADEV

, 07731 732-886-5960 office 908-901-9193 cell -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of jimlux Sent: Sunday, November 14, 2010 11:49 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] ADEV David I

Re: [time-nuts] ADEV

On Sat, Nov 13, 2010 at 07:01:26AM -0800, jimlux wrote: To the Ku-band downconverters.. They're pretty crummy (but have a decent SNR to work with).. however, I've seen that there are two kinds.. a vanilla LNB and ones described as crystal locked... both are cheap ($20-30 for the former,

Re: [time-nuts] ADEV

David I. Emery wrote: On Sat, Nov 13, 2010 at 07:01:26AM -0800, jimlux wrote: To the Ku-band downconverters.. They're pretty crummy (but have a decent SNR to work with).. however, I've seen that there are two kinds.. a vanilla LNB and ones described as crystal locked... both are cheap

Re: [time-nuts] ADEV

On 11/14/2010 7:24 PM, David I. Emery wrote: 3. External reference LNBs with 10 MHz (pretty universal) going up the cable that also carries power and brings the L band signal down. I'm not entirely sure how many of these designs simply bandpass filter and then limit the 10 MHz and use that

Re: [time-nuts] ADEV

On 11/13/2010 02:20 PM, Mike Feher wrote: I sure do agree, that with very low data rate systems it is significant. In fact, when David Allan Fred Walls came up with the proposal of using this measurement as an FOM for oscillators over 30 years ago, digital communication rates were slow, and,

Re: [time-nuts] ADEV

-5960 office 908-901-9193 cell -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Saturday, November 13, 2010 9:06 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] ADEV Hi I see ADEV

Re: [time-nuts] ADEV

Hi Bob, On 11/13/2010 03:05 PM, Bob Camp wrote: Hi I see ADEV not as a solution to a system design problem, but an oscillator measurement issue. If you look at the measures being used in the 60's, most of them had serious statistical flaws. You could measure them several ways and get

Re: [time-nuts] ADEV

Mike Feher wrote: I sure do agree, that with very low data rate systems it is significant. In fact, when David Allan Fred Walls came up with the proposal of using this measurement as an FOM for oscillators over 30 years ago, digital communication rates were slow, and, the measurement was a good

Re: [time-nuts] ADEV

Magnus Danielson wrote: Hi Bob, snip I think the system applications for short-term stability measurements was quite clear, and was brought out specifically. Basically, these are all systems where there is some storage or delay and you are comparing a signal generated/recorded at some

Re: [time-nuts] ADEV

Hi I don't see anybody arguing that systems work better when there's a high ADEV than a low ADEV. Most of the papers are heading in the direction of it doesn't catch all of the problems I worry about. Based on what systems need and what ADEV measures, I don't find that a particularly

Re: [time-nuts] ADEV

On 11/13/2010 04:01 PM, jimlux wrote: Mike Feher wrote: I sure do agree, that with very low data rate systems it is significant. In fact, when David Allan Fred Walls came up with the proposal of using this measurement as an FOM for oscillators over 30 years ago, digital communication rates

Re: [time-nuts] ADEV

Magnus Danielson wrote: One of the big meetings on this topic was in the NASA Goddard space center, and the result of that is found in the NASA Special Publication 80 (SP-80): http://hdl.handle.net/2060/19660001092 Un the part 1 User's viewpoint and requirements First article in there is

Re: [time-nuts] ADEV

Bob Camp wrote: Hi I don't see anybody arguing that systems work better when there's a high ADEV than a low ADEV. Most of the papers are heading in the direction of it doesn't catch all of the problems I worry about. Based on what systems need and what ADEV measures, I don't find that a

Re: [time-nuts] ADEV

On 11/13/2010 04:53 PM, jimlux wrote: Magnus Danielson wrote: One of the big meetings on this topic was in the NASA Goddard space center, and the result of that is found in the NASA Special Publication 80 (SP-80): http://hdl.handle.net/2060/19660001092 Un the part 1 User's viewpoint and

Re: [time-nuts] ADEV

And, on the one hand, it's frustrating being the orphan child of the RF user community: you can't get off the shelf test equipment. On the other hand, it's cool, because then you have to *build* your test equipment. Hmm. Should do more of that. Well, one *does* have to convince someone to

Re: [time-nuts] ADEV

On 11/13/2010 05:32 PM, jimlux wrote: And, on the one hand, it's frustrating being the orphan child of the RF user community: you can't get off the shelf test equipment. On the other hand, it's cool, because then you have to *build* your test equipment. Hmm. Should do more of that. Well,

Re: [time-nuts] ADEV vs MDEV

Bob Camp wrote: Hi I believe the statement: Both systems are equally limited by the reference oscillator was part of the same paragraph as the comment on 10811 short term stability. Neither system, no matter how well set up will get below the stability of the reference oscillator. For

Re: [time-nuts] ADEV vs MDEV - using sound card

Bob Camp wrote: Hi My main concern with the low frequency pole in the sound card is the quality of the R/C used. You can certainly model what ever you have. If they used an aluminum electrolytic for the C it may not be the same next time you check it Do consider to bypass it. This is

Re: [time-nuts] ADEV vs MDEV - using sound card

Magnus Danielson wrote: Bob Camp wrote: Hi My main concern with the low frequency pole in the sound card is the quality of the R/C used. You can certainly model what ever you have. If they used an aluminum electrolytic for the C it may not be the same next time you check it Do

Re: [time-nuts] ADEV vs MDEV - DMTD sound card

Hi That was actually talking about a heterodyne system. Indeed a good digitizer could be used with a DMTD. One thing I have not looked into is the DC accuracy required if you go that way. Some of these approaches have odd little gotcha's. By analogy with a heterodyne setup it might not.

Re: [time-nuts] ADEV vs MDEV

Hi Pete, typical for theHP5370A/B, the SR620 or the CNT81/91. I have data from my CNT81showing MDEV 1E-13 in 10s. and I believe the other counters behave similarly. Pete Rawson I have a CNT81 and a TI GPIB-card, that are not yet close friends. Could you tell me a bit about your measurement

Re: [time-nuts] ADEV vs MDEV

Hi The counter is not the big issue in DMTD. We seem The problems lies elsewhere. I think we've gone into that pretty deeply in various recent threads. As a practical bench instrument, the Pendulums are a very good choice. That's independent of anything having to do with DMTD. Bob On Feb

Re: [time-nuts] ADEV vs MDEV

Bruce Griffiths wrote: _Correction_ Oops, Its the CNT91 not the CNT81 that actually does the regression fit. How did you achieve MDEV ~1E-13 @10s with a counter rated at 50ps single shot resolution? I think the actual resolution and trigger jitter was combined to a single number. For some

Re: [time-nuts] ADEV vs MDEV

Pete Rawson wrote: Efforts are underway to develop a low cost DMTD apparatus with demonstrated stability measurements of 1E-13 in 1s. It seems that existing TI counters can reach this goal in 10s. (using MDEV estimate or 100+s. using ADEV estimate). The question is; does the MDEV tool provide an

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