AD box noise

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Thomas
Posts: 2
Joined: Fri Apr 30, 2010 3:21 pm
Location: Montreal

AD box noise

Post by Thomas »

Hello,

We recently noticed a noisy signal from our active two AD box. When we are recording our AD box signal (without any channels connected to the box) we can see a noisier signal from plugs A, B and EXG (those we are routinely using during our experiments) than from plugs C, D, E, F, G and H (flat signal; never used during experiment).
This is an example of what kind of signal we have on plugs A, B and EXG :
http://img820.imageshack.us/img820/9599/noiseab.jpg
http://img546.imageshack.us/img546/1363/noiseexg.jpg

We are using our bisoemi EEG since last year and the signal was flat for every plug including A&B until now. Is it a technical problem ?

Thank you
Thomas

Coen
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Posts: 1125
Joined: Fri Mar 26, 2004 7:00 pm
Location: Amsterdam, Netherlands
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Post by Coen »

The channels with installed amp/ADC modules show baseline noise, the channels without modules show a flat line (no ADC output). Your system has always been this way (64+8 amp/ADCs installed), it's normal.

Best regards, Coen (BioSemi)

Thomas
Posts: 2
Joined: Fri Apr 30, 2010 3:21 pm
Location: Montreal

Post by Thomas »

Thank you Cohen.
Another question : is there a way to reduce the gain and improve our signal/noise ratio ? Via "Analog input box" in ActiView ?
Thank you
Thomas

Coen
Site Admin
Posts: 1125
Joined: Fri Mar 26, 2004 7:00 pm
Location: Amsterdam, Netherlands
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Post by Coen »

Please explain explain why decreasing the gain would in your view improve the S/N ratio.

Best regards, Coen

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