[time-nuts] About HP10544A

J. L. Trantham jltran at worldnet.att.net
Sat Mar 7 19:44:19 UTC 2009

I tried to view the files on amigazone but was 'denied'.

Any way to get a look?  Am I doing something wrong?

I tried with IE 7 and FireFox with no luck.

I have several 10544A's and they all put out a 10 MHz signal but it is sort
of a 'ramp like' wave as viewed on the oscilloscope that looks rich in
harmonics.  My 10811's seem to have a pure sine wave though I have not
looked at it on a spectrum analyzer yet.

I was going to get around to asking the same question about the 10544A's.
Are all mine bad or is this normal function?



-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
Behalf Of Esa Heikkinen
Sent: Saturday, March 07, 2009 11:58 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] About HP10544A


I got one of the 544's and plan to use it for rubidium cleaning loop
(Efratom LPRO). But I cannot get a clean 10 MHz signal out from it!
There are harmonics and spurious. I know that spurious come from oven
swicther so those should be easily handled with separate oven supply.

But the bigger problem are the harmonics:

This spectrum is measured with emitter follower buffer connected to
output which is terminated with 1k like datasheet recommends. So the
load should be ideal but still distorted. The distortion can be seen
even with oscilloscope:

So it ooks like negative half cycle is distorted.

As a reference, THIS is the signal to be cleaned with HP10544A:


So... I believe that there may be something wrong with HP10544A if it's
output is worse than lower grade xtal oscillators used in LPRO etc.

But just to make sure I'm asking you guys having these oscillators.
Should it even give clean sine wave or not? And if it should, where
should I start to seek the fault?


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