[time-nuts] Question on HP5359 Time Synthesizer

Ulrich Bangert df6jb at ulrich-bangert.de
Mon Jun 23 02:18:52 EDT 2008


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
Ortholzer Weg 1
27243 Gross Ippener 


While I am writing this the drift rate has reduced to abt 1 HZ / sec.

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