Reply-To: "Kevin Aylward"
From: "Kevin Aylward"
Subject: Re: Niosy A/D converter - an advantage ?
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Date: Thu, 14 Nov 2002 07:54:35 -0000
NNTP-Posting-Date: Thu, 14 Nov 2002 07:54:41 GMT
"Roger Lascelles" wrote in message
> We have 12 bit ADC in a product. Due to grounding problems, the ADC
> readings fluctuate - I don't know exactly by how much, but lets say at
> the last two bits dither around. The noise is digital hash from the
> microprocessor which has external RAM and ROM.
Its probably not really "noise" then, but "interference".
> Because the AD for is only used to measure periodic or DC quantities,
> programmer has added a lot of averaging code which produces smooth
> to an equivalent of 13 bits resolution. He claims that the noise is
> advantage, because it dithers the AD to permit averaging.
For gausssian white noise, maybe, but in this case you probably have
digital/power line garbage where this wont work.
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