> I'll also be doing comparisons, to my current (Frequency division &
Heterodyne) detectors.
Hi Al,
You might also try the free Avisoft-SASLab Lite software (http://www.avisof=
t.com/setup3.exe, http://www.avisoft.com/SASLabPro.pdf).
There is an interesting feature in it that might help to become familiar wi=
th the differences between time expansion and frequency division bat detect=
or technology: The menu 'File'/'Specials'/'Frequency Division Bat Detector =
Emulation' can convert high sample rate recordings (such as those made with=
a USB ultrasound microphone) to a waveform that corresponds to the output =
signal that you would hear if you recorded the bat by using a frequency div=
ision bat detector.
Use the Command 'File'/'Playback setting...' to play your bat recording at =
lower speeds (option 'other sample rate.'). You could also try the undersam=
pling option (undersampl:) that performs a real-time broad-band conversion.=
This is probably the same mechanism that Gianni is going to implement now.=
Note that I (probably first) introduced this principle to bat detector tech=
nology in 1993 (implemented in the Laar Bridge Box time expansion detectors=
). It is now also available in the (more expensive) UltraSoundGate USB micr=
ophones supported both by hardware and software. The hardware implementatio=
n has the advantage that there is virtually no delay between the occurrence=
of the ultrasounds and the converted output signal (just like in a convent=
ional bat detector). This can be very important as the delay caused by a so=
ftware solution can be annoying.
Regards
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