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Date: Fri, 6 Mar 2015 10:12:09 -0500
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Subject: Re: [geda-user] [OT] Temperature sensor and control recommendation
From: Bob Paddock <graceindustries AT gmail DOT com>
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On Fri, Mar 6, 2015 at 9:55 AM, Evan Foss <evanfoss AT gmail DOT com> wrote:

> Why is everyone assuming this should be done digitally?

Tradition?

"The synchronous detectors were used in temperature monitors and
temperature controllers designed to control temperatures on spacecraft
at 60 milliKelvin +/- a few ucroKelvin. The preamplifier had to have a
gain of 10E5 after which the demodulated signal had to be converted by
a 16 bit ADC, with +/- 1LSB allowable error.... so of course, you can
see that we were working with extremely small signals buried in the
noise, and we had to go all out in an effort to beat down the noise.
That's why we had to use a new improved synchronous demodulator. This
project was as close to being impossible as you can get! I still have
trouble believing that we actually made it work." -- John Sutton of
NASA : https://web.archive.org/web/20120607001807/http://www.unusualresearch.com/Sutton/sutton.htm