The output of the diode detector is compared with the dc base voltage of
the oscillator transistor adjusting the oscillator transitor current
whenever the detector output deviates from
Oscillator transistor base voltage - 2*Vbe.
Bruce
Nick Foster wrote:
Thanks for the quick reply, John.
From: [email protected]
Okay, 12V on the oscillator (pin 3) and 20V on the oven (pin 14). How much
on the oven controller, pin 8?
+12V. The oscillator uses the same supply as the filter, with the addition of a
10mH inductor + decoupling caps.
Are pins 2, 4, 5, 9, and 15 grounded? Pin 6 (EFC) should be grounded for
initial testing.
Yes and yes.
Upon looking further, something jumped out at me: the output is 2.2V RMS into
1000 ohms instead of the 1V RMS spec'ed in the datasheet. So I suppose the
problem might be in the AGC circuitry, instead of the output emitter follower.
It doesn't look as though the AGC in this oscillator contains a trimpot, like
the 10811 does.
I'm using the schematic at http://www.leapsecond.com/museum/10544/10544-3.gif,
but I don't have a good idea of how that AGC works.
--n
From: [email protected]
To: [email protected]
Date: Fri, 15 Jan 2010 15:06:42 -0500
Subject: Re: [time-nuts] HP 10544A with dodgy output?
Okay, 12V on the oscillator (pin 3) and 20V on the oven (pin 14). How much
on the oven controller, pin 8?
Are pins 2, 4, 5, 9, and 15 grounded? Pin 6 (EFC) should be grounded for
initial testing.
John WA4WDL
--------------------------------------------------
From: "Nick Foster"<[email protected]>
Sent: Friday, January 15, 2010 2:53 PM
To:<[email protected]>
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 -- [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.
_________________________________________________________________
Hotmail: Free, trusted and rich email service.
http://clk.atdmt.com/GBL/go/196390708/direct/01/
_______________________________________________
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.
