Working with Freq

[epilot]

Hi,

Just like to know if there is any circuit to convert the ultrasonic freq caused by a bat audible?
something like dividing the freq by2 or 3?

again is this possible and is there any circuit to convert the audio into ultrasonic? something like doubler or...?

many thanks

 

[HarveyH42]

Search for 'Bat Detector'. There are kits under $30, and have seen several circuits on the web.

 

[Hero999]

Normally a heterodyning is used, it's a fairly common technique that's also used in radios.
http://www.google.com/search?client...rodyne+radio&sourceid=opera&ie=utf-8&oe=utf-8

 

[audioguru]

The down converted sounds from bats will be just "clicks". You won't hear them talking to each other about YOU!

 

[Sceadwian]

Some modern sound cards can sample at up to 190khz. That gives you a max detection frequency of 96khz. The first hit I found on google says bats go up to 100khz. Close enough.

 

[epilot]

The down converted sounds from bats will be just "clicks". You won't hear them talking to each other about YOU!

LoL, yea I know, but wanted to be sure that they are not talking about me



well I was think about a circuit which is able to mulitiple the comming freq by 2 or 3 and perhaps devide it by 2 or 3! no I am not taliking about heterodyning, but something like a chip which is able to convert the audio and ultrasonic spectrum...

 

[audioguru]

A phase-locked-loop IC can be combined with a counter IC to multiply a digital frequency.