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1. Re: Initial SASS test shows bands of harmonics

Subject: 1. Re: Initial SASS test shows bands of harmonics
From: "Raimund" animalsounds
Date: Sun Mar 11, 2012 4:33 pm ((PDT))
Peter Shute <> wrote:

> But perhaps Raimund is right, that it's caused by the PIP struggling with=
 4 capsules. Can anyone recommend a battery circuit I could try? I was goin=
g to look into this anyway. Is it safe to just put a voltmeter across a cap=
sule to check it?

Hi Peter,

Yes, that should be possible. I did that with two EM172 capsules connected =
to one channel of the PCM-M10. The voltage was floating around between 0.4 =
and 0.6 V. Four capsules would of course make it even worse. I believe that=
 such a low voltage would also increase the effective output impedance of t=
he capsules. High output impedances generally increase the risk to pick up =
electromagnetic interferences, which would be an explanation for the interf=
erences that you faced.

The recommended PIP battery circuit can be found in the data sheet:

http://www.frogloggers.com/Documents/EM172.pdf

The capacitor determines the cutoff frequency of the high pass filter that =
is formed by this capacitor and the input impedance of the recorder. A suit=
ed value would be for instance 220 or 470 nF.

Regards,
Raimund








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