PSN-L Email List Message

Subject: Re: Amplifier noise?
From: Jim Hannon jmhannon@........
Date: Sat, 23 Dec 2000 08:05:37 -0600

I think that what you are seeing is about the noise level of Larry,s  16 
bit A/D card. You can check this by operating the A/D card with it's input 
shorted. Check the noise level and see how it compares to the noise when 
your amplifier is connected.

At 08:53 PM 12/22/00 -0600, you wrote:

>Hello Everyone,
>Recently I finished construction on my first seismometer.  I used
>schematics off of Larry Cochrane's web site to wire wrap the amplifier:
> and
>I housed the amplifier in a steel box, grounded to analog ground on the
>amplifier board.
>I have the output of the amplifier connected to Larry's 16 bit A to D board
>with about 16 feet of shielded wire.  The shield, around the wire, is
>grounded to the case of my computer.  When viewing the output with SDR I am
>getting about 80 to 100 counts of continuous noise.  I don't know what the
>frequency of the noise is but the period is too short to see on SDR.
>Is this noise level abnormally high and does anyone have any suggestions on
>how to reduce the noise.
>Thanks for your time!

Jim Hannon


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