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Re: The Ultramic200K - Avisoft ultrasound monitoring technology

Subject: Re: The Ultramic200K - Avisoft ultrasound monitoring technology
From: "Raimund" animalsounds
Date: Sat Apr 9, 2011 2:15 am ((PDT))
Hi Gianni,

I'm sorry that this discussion is getting so hot...

> I'm sorry to say that the option described by Raimund is not an emulation=
 of
> the frequency division principle, is only a resampling without the requir=
ed
> low pass filtering and thus the resampling produces aliased components wh=
ose
> only merit is to made audible, but highly distorted, the components above
> the Nyquist frequency of the resampling.

Yes, this is the broad-band monitoring (under-sampling) option that I also =
mentioned.

> A real frequency division system is based on a zero crossing algorithm th=
at
> produces a sine cycle every n cycles in the original signal; thus it
> produces a synthetic signal whose amplitude is modulated by the amplitude=
 of
> the original signal.

Of course, this exactly what the SASLab Lite / Pro command File'/'Specials'=
/'Frequency Division Bat Detector
Emulation' does. See how it looks like:

http://www.avisoft.com/FrequencyDivision.pdf

There is however of course some distortion as in most other hardware-based =
frequency division bat detectors too.

Regards,
Raimund








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