Bat detector electronics, was Re: 50kHz pitch shifter

[Donald Johnson]

This web site has some reasonably easy circuits for converting
ultrasonic sounds:
 Bertrik's bat detector page
http://phoenix.student.utwente.nl/~bertrik/bat/bat_indx.htm

René Schmitz wrote:
> At 09:39 13.06.00 +0200, you wrote:
> 
> >And I've heard about people recording bats. Now , tape recorders are made
> >for the audio band, they will not work. Same applies for most sampling
> >technology. Frequency shifting will destroy harmonic relationships.
> >
> >Any ideas?
> 
> A few years ago there used to be an article in Elektor describing a device
> with a balanced modulator that could be used to bring bat sounds into the
> audio band. I do see the point of the destroyed harmonics, but I can't
> understand bat language anyway, so the question is if this matters at all.
> 
> And a related thing is the "infra red microphone" which can be used to
> listen 
> to the sounds of events in light. Like the "sound" of a candle or fire. 
> 
> Bye,
>  René

 don.
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