The 10544A is specified for a 1000 Ohm load.
John WA4WDL
--------------------------------------------------
From: "David C. Partridge" <david.partri...@dsl.pipex.com>
Sent: Friday, January 15, 2010 3:11 PM
To: "'Discussion of precise time and frequency measurement'"
<time-nuts@febo.com>
Subject: Re: [time-nuts] HP 10544A with dodgy output?
What impedance loading is the output specified for? 1M or 50R.
Could I suggest using a distribution amp?
Dave
-----Original Message-----
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Nick Foster
Sent: 15 January 2010 19:53
To: time-nuts@febo.com
Subject: [time-nuts] HP 10544A with dodgy output?
Hi all,
I've just built a GPS-disciplined oscillator built around a 10544A,
somewhat
in the style of the Brooks Shera unit, just to use around the shack.
Problem
is, now that it's wired up, I notice the output is heavily distorted. It's
clipped on the negative side of the waveform, like an emitter follower
without enough headroom. The more I load the oscillator output, the
heavier
the clipping. When I load the oscillator output with 1000 ohms, spec for
this unit, almost 30% of the waveform is clipped on the negative side. If
I
don't load it at all and just put a probe on the output, it looks OK, but
still some flattening of the bottom half of the waveform.
I've got it wired up according to the datasheet, with +12V on the
oscillator
and +20V on the heater. The grounds for the oscillator/amplifier, oven
controller, heater, and output are all tied together.
I know these are old units, and I'm wondering if this is a problem (for
instance in the output emitter follower amp) that others know about,
before
I tear into it looking for a solution.
Thanks for your time,
Nick
_________________________________________________________________
Your E-mail and More On-the-Go. Get Windows Live Hotmail Free.
http://clk.atdmt.com/GBL/go/196390709/direct/01/
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
