Cross talk in ADC channel due to noise on PCB

Started by fatimak 1 year ago5 replieslatest reply 1 year ago136 views

Hi,

    I am working on a board with 4 Dual-Channel ADC ADS42LB69 and though the ADC has a 100 dB channel isolation the cross talk on the channels due to PCB noise produces degradation in channel isolation I wanted to find out if it is possible to remove any of the noise on the channels through software or filtering.

Thankyou

Fatima

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Reply by dudelsoundApril 26, 2017

That depends if your "noise" is crosstalk (correlated) or noise. If it is crosstalk, you could try to remove it using a short adaptive filter:

ChB' = ChB - AdaptFIl ** ChA.

And then adapt the filter with some very slow LMs algorithm. Very slow because you are looking for very low influence...

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Reply by fatimakApril 26, 2017

Thankyou so much will look into the solution you recommend.

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Reply by jms_nhApril 26, 2017

Are you sure it's noise and not ADC driving issues? https://www.embeddedrelated.com/showarticle/110.ph...

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Reply by fatimakApril 26, 2017

Yes as the board manufacture has it on the datasheet that the board has an 80dB crosstalk something which was overlooked during board selection. But thank you will read through the article to see if there is a mistake in driving the ADCs which might be adding to the noise floor

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Reply by SlartibartfastApril 26, 2017

There are a number of different crosstalk removal methods depending on what your signals are and how much processing you can do.  If the crosstalk characteristic is stable, you may be able to calibrate it out using some test signals.   Also look into NEXT (near-end-cross-talk) cancellation as used in DMT and other wired comm standards.