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RE: Minidisk data transfer and bat recordings

Subject: RE: Minidisk data transfer and bat recordings
From:
Date: Fri, 23 Jan 2004 20:12:32 +0100 (MET)
Graham,

I would agree with Walt that MD should have no trouble in reproducing the
sounds produced by a bat detector.

Your frequency division detector produces a relativlely crude output signal
that can't be seriously degraded by compression at all.

The time expansion detector has internally 8 bit A/D and D/A converters
which provides a relatively limited dynamic range only. Therefore, the stro=
ng
inherent quantization noise of the that detector will mask the quantization
noise that might be added by a MD recorder.  The 10:1 time expansion will
transpose a 110 kHz bat call down to 11 kHz. So there would be no much ener=
gy at
higher frequencies that could push the MD recorder to its limits.

Regards,
Raimund



>The monitoring work is being done with Stag Duet Frequency Division
>detectors, which divides the original frequencies by 10 and will only pick
>up frequencies in the range 17kHz to 125Khz, so I'm not sure what that
means
>in terms of the MD capabilities.

>The other detectors we use are Petterson D240x which is a time expansion
>model, expanding the signals by a selectable x10 or x 20. The frequency
>range is 10 -120kHz and the sampling frequency is 307kHz.

>Again I must leave it to the experts to comment on the suitability of the
>MDs to record these ranges.

>Graham

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