From: Dwayne Reid <dwayner@planet.eon.net>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Mon, 10 Aug 2020 13:14:14 -0700
Subject: Re: [EE] averaging multiple samples to reject AC interference
Thread-Topic: [EE] averaging multiple samples to reject AC interference
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Hi there, Bob.

Old-time Dual-Slope digital meter systems did exactly what you=20
describe, with great effectiveness.

dwayne


At 01:44 PM 8/10/2020, Bob Blick wrote:
>I have sensors that feed an instrumentation amplifier running a=20
>voltage gain of 10 before going into the A/D converter of a microcontrolle=
r.
>
>There is AC line interference. It is small, but if I can reduce the=20
>effect, that would be good. I'm in the 60 Hertz part of the world,=20
>but ultimately this will be used in both 50Hz and 60Hz locations.=20
>Battery operated, this is not conducted interference or power supply=20
>ripple. Shielding is not possible. I only need to process the signal=20
>about 4 or 5 times per second. The signal is changing, so long-term=20
>averaging is bad. Actually any averaging will result in a tradeoff=20
>between response time and accuracy that I will need to evaluate.
>
>These sensors are multiplexed with others and I can't sample continuously.
>
>If I average multiple samples taken at 1/300 second intervals over a=20
>1/10 second period, that should give some improvement at 50Hz and=20
>60Hz without getting too involved, correct? This would fit into my=20
>existing multiplexing constraints.
>
>I seem to recall being in this situation before but forget what I=20
>did at the time.
>
>Thanks for any suggestions.
>Bob


--=20
Dwayne Reid   <dwayner@planet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
780-489-3199 voice   780-487-6397 fax   888-489-3199 Toll Free
www.trinity-electronics.com
Custom Electronics Design and Manufacturing

--=20
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