Re: Determining peak frequencies - bats

["Avocet" madl74]

> I'd be assuming that biology students recording insects would be
> using equipment that could handle the expected frequencies.

Vicki,

For bats, we use heterodyne frequency shifting (HD), frequency 
division (FD) and time expansion (TE) bat detectors. FD usually divide 
by 10 and TE record a second or so and play it back at a fraction of 
the speed. I'm one of the authors of
http://en.wikipedia.org/wiki/Bat_detector

FD detectors reconstruct the waveform but TE preserve it so it can be 
recorded on a an audio recorder and read by audio frequency analysis 
software at typically 1/10 or 1/16 rate. These would also give good 
results with ultrasonic insects. BTW crickets are a pain when trying 
to record bats, especially the U/S ones. :-)

David

David Brinicombe
North Devon, UK
Cogito cogito ergo cogito sum - Ambrose Bierce