[time-nuts] Temperature sensors and bridge amps

Harry Brown harryhbrown at earthlink.net
Mon Nov 15 19:00:38 UTC 2010


Back in the early 80's I was working for a company making military 
communication satellites.

The 5 MHz Oscillators used on the satellite were in a double oven keeping 
the oven temp within 0.001 Hz C.

We could adjust the oscillator frequency for aging by ground commanding a 
bank of relays controlled a D/A converter to adjust  the oscillator 
frequency.

Lots of fun back then.

 Any idea what is used now?

73, Harry, W3IIT

----- Original Message ----- 
From: "Richard Karlquist" <richard at karlquist.com>
To: <time-nuts at febo.com>
Sent: Saturday, November 13, 2010 10:48 AM
Subject: Re: [time-nuts] Temperature sensors and bridge amps


> The HP E9183A achieved 1 millidegree over -55 to +85C
> in a single oven. The time lag was dealt with by adding
> a double integrator to PID.
>
> Rick Karlquist N6RK
>
> On Fri 12/11/10 8:26 AM , "Bill Hawkins"  wrote:
>
> in the heater control loop. Of course, you can't get to a
> millidegree from ambient with just one oven. And you can't
> eliminate time lags if you have any thermal mass.
>
>
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