Poul, Bruce and Greg thanks for your help. I see a lot clearer now! The manual can be downloaded from Didier's manual web page
http://www.ko4bb.com/cgi-bin/manuals.pl?dir=HP_Agilent Best regards Ulrich > -----Ursprungliche Nachricht----- > Von: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Im Auftrag von Greg Burnett > Gesendet: Montag, 23. Juni 2008 10:56 > An: Discussion of precise time and frequency measurement > Betreff: Re: [time-nuts] Question on HP5359 Time Synthesizer > > > Ulrich, > > Your HP 5359A observations are normal, and many other HP > 5359A users have > asked exactly the same question, down through all these years > since the box > was first introduced. The main point is that the HP 5359A's > purpose is > *only* to generate precise timing. The box wasn't intended to > generate > precise frequency because, in its 'frequency mode' it only generates > *approximate* rates by "kicking (triggering) itself in the pants" > repetitively. (Therefore it is *not* a frequency synthesizer and its > "frequency" is not phase-locked to its timebase.) > > Interesting note: Despite fact that the HP 5359A is not designed to > synthesize nor lock its "frequency" to its timebase, if you set its > frequency for "10 MHz" it sometimes might actually > synchronize itself to its > 10811A timebase. This interesting effect only occurs at 10 MHz and > apparently is a sympathetic synchronization effect due to > ground loop and > proximity coupling between circuitry and the timebase 10 MHz > signal. ...This > is a very weak effect, is not by design, and, again, can only > occur for > frequency settings of exactly 10 MHz. > > Cheers, > Greg > > ----------------------------------- > > Ulrich wrote: > > Gentlemen, > > some time ago I had the possibility to buy a surplus HP5359 > Time Synthesizer. As far as I can judge from my measurements > with a HP5370 and a SR620 the two delays that are generated > inside the box with high precision are ok and completely > within the specs, which is the most important feature for me. > > There is however one annoying fact: If I use the instrument > in "frequency" or "period" mode, where the negative slope of > the second delay generator is used to trigger the first delay > generator in order to generate a repetitive waveform, I > notice that a few moments after I have pressed the > "calibration" button (which should adjust everything > automatically) the frequency of the repetitive waveform will > change and drift by an amount of some 100 Hz up to a few kHz > so that my counter may read 996 kHz after a few minutes with > the drift getting smaller over time as the device warms up. > > I have first thought that this effect is due to a defective > 10811 in the box but the effect is the same with an > externally supplied standard frequency. Well, the thing is: > If one reads the manual carefully he will find out that there > is no spec about frequency stability to be found anwhere in > it! On the other hand the manual says to check the "trigger > assembly" in case of coarse "overall timing errors". The > trigger assembly is the point where the negative slope of the > second delay generator is feed back into the trigger circuit > to make the waveform repetitive. Am I complaining at > something completely Ok or should I have a deeper look to the > trigger circuits? Hopefully one of you 5370 adepts can give > some explanation. > > Ulrich Bangert > www.ulrich-bangert.de > Ortholzer Weg 1 > 27243 Gross Ippener > > P.S. > > While I am writing this the drift rate has reduced to abt 1 HZ / sec. > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-> bin/mailman/listinfo/time-nuts > and > follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
