PSN-L Email List Message

Subject: Note On Noise
From: "Geoffrey" gmvoeth@...........
Date: Sat, 26 Dec 2009 11:52:30 -0700

You guys with those low freq sensors below 5 seconds
seem terribly plagued by noise either seismic
or weather or whatever. I was wondering if it
is possible for you to study the noise when
no EQ are present then use that data to somehow
filter out the background stuff and this may
serve to enhance the eq stuff.

To me your signals appear swamped with noise
at the same freq as the signal which literally
makes it impossible to filter out the noise.

If you are not anti alizing things you could be getting
noise from much higher more intense things like
air conditioners and other machines on the ground.

A 26 Hz signal may look like one Hz if it alizes
with a 50SPS sample rate.

Just a thought,

ps has anyone ever put their device into a vacuum chamber
to eliminate air / air buoyancy changes from effecting
their noise levels ?

Surrounding their device with gallon jugs filled with water
at room temperature to act as a thermal condenser ?
( moderate temp changes )

things like this ???


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