Hi Dave -- I'll try to get it uploaded in the next day or two. I'll report back the URL once I know what it will be.
73, John ---- [EMAIL PROTECTED] wrote: > Interestingly I asked around 50% of this question in person to John > Ackermann at microwave update saturday afternoon. My special interest was > what commands to send to the 5370a through the HPIB to generate the txt file > need by Alavar > > John > Did you get round to uploading the .ppt...especially interested in the Gerd > curtailed part! > > Dave > > WW2R > >> Message: 3 >> Date: Sun, 22 Oct 2006 00:29:14 -0500 >> From: Didier Juges <[EMAIL PROTECTED]> >> Subject: [time-nuts] How to measure Allan Deviation? >> To: Discussion of precise time and frequency measurement >> <[email protected]> >> Message-ID: <[EMAIL PROTECTED]> >> Content-Type: text/plain; charset=ISO-8859-1; format=flowed >> >> OK, here is my problem. I do not think it is a unique problem, based on >> recent mail :-) >> >> I have read about the Allan Deviation and I understand the principle, >> even though the nuances between the 3 basic Allan deviations escape me >> at the moment, but I am sure it will come once I re-read the Help file >> that comes with the the AlaVar software , and I have downloaded and >> installed AlaVar, a free software that can compute the various flavors >> of the Allan Deviation. >> >> I have a working HP 5370A, which I believe is required (even though >> maybe other counters, such as the HP 5334 or HP 5316, both of which have >> a TI function that might be used for that purpose) to gather the data >> that will be fed into AlaVar. >> >> I have a working GPIB interface (actually several types) and a computer >> attached to it, and I can write a Visual Basic programs to talk to the >> counter and download data (I have already written Visual Basic/GPIB >> programs to control signal generators, power meter, spectrum analyzers >> and other instruments). >> >> I have several HP 10811 oscillators (with EFC input), and a couple of >> Ovenair (also with EFC input for at least one of them), some are inside >> working HP instruments, and a couple are spares. >> >> What I do not have is a procedure. What data do I need to feed the >> software and how do I actually collect the data? >> >> I assume the 5370 should be set to measure TI between 2 oscillators. >> Should I use the built-in averaging function? What sample size and >> resolution should I use? Should I try to use the 5370 in raw mode (much >> faster, 6000 samples/sec) or in formatted mode (10-20 samples/sec)? Does >> it make a difference? >> What if the oscillators are not phase locked and show frequency drift? >> >> The 5370 has a 10811 oscillator for its time base, so it is good but no >> better than any of the oscillators I want to check. Do I use it as a >> reference, or do I compare two stand-alone oscillators? >> >> How do I know which oscillator I am measuring when the two oscillators I >> am comparing are the same models? Should I compare 3 or more? >> >> Regarding the GPS receiver, I thought most modern GPS receivers >> automatically switch from nav mode to survey mode when they stop moving. >> I would probably be mistaken to believe this is comparable to a true >> time-keeping GPS receiver, but how bad is it? Tom Clark wrote previously >> on Time-Nuts that his experience with the Jupiter was good, with +/- 13 >> nS jitter, other than the fact the receiver will not return the timing >> error on the next pulse, which prevents from writing smart software that >> can compensate for it. >> >> I have a Jupiter GPS receiver which I intend to use to discipline one of >> the 10811 oscillators. The Jupiter receiver has a 10kHz output, which >> would simplify the phase lock loop a little (even though it would not >> allow to speed up the loop). Is there any disadvantage in using it >> instead of the 1PPS output? It seems the 10 kHz would be easier to >> filter, and maybe allow to speed up the loop following power up >> (assuming it is set to the normal, longer time constant once phase lock >> is achieved), but what do I know? >> >> I also have a modified distribution amplifier to distribute the good 10 >> MHz to my lab without affecting the master oscillator. >> >> So I am anxious to use the AlaVar software and the toys I have listed >> above to do the following: >> >> 1) select the best OCXO to be the basis of my GPS disciplined frequency >> standard >> 2) find the best placement for the GPS antenna (the one that gives the >> most stable GPS signal) >> 3) fine tune the phase lock parameters and estimate the quality of the >> end product >> >> Any further information and guidance (with practical tips) would be >> greatly appreciated. >> >> Didier KO4BB >> >> > > > > _______________________________________________ > time-nuts mailing list > [email protected] > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
