[time-nuts] Temperature sensors and bridge amps

[Javier Herrero]

And more important... they do not consume power continuously ;)

Regards,

Javier

El 15/11/2010 20:18, Alan Melia escribió:
> Maybe the same things Harry ?? The advantage of latching relays is that they
> maintain the position (EFC) if you lose the command link. You cant hear the
> "clicks" in Space
>   :-))
> Alan
> G3NYK
> ----- Original Message -----
> From: "Harry Brown"<harryhbrown at earthlink.net>
> To:<richard at karlquist.com>; "Discussion of precise time and frequency
> measurement"<time-nuts at febo.com>
> Sent: Monday, November 15, 2010 7:00 PM
> Subject: Re: [time-nuts] Temperature sensors and bridge amps
>
>
>> 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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>>
>>
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-- 
------------------------------------------------------------------------
Javier Herrero                            EMAIL: jherrero at hvsistemas.com
Chief Technology Officer
HV Sistemas S.L.                          PHONE:         +34 949 336 806
Los Charcones, 17                         FAX:           +34 949 336 792
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