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Re: Bat detector calibration

Subject: Re: Bat detector calibration
From: "Peter Shute" pshute2
Date: Sun Mar 20, 2016 3:34 am ((PDT))
I've now tried 6 computers, and can't get any of them to output higher than=
 about 20kHz. I asked the same question on the Audacity forum, and got this=
 response "Most soundcards have anti-aliasing filters to keep them from goi=
ng beyond audibility (20KHz)."

I'm thinking that either I'm doing something wrong (quite likely), or suita=
ble sound cards aren't that common.

I think I will have to try Ivano's suggestion of the signal generator.

Peter Shute

Sent from my iPad

On 18 Mar 2016, at 8:11 PM, <raimundspec=
> [naturerecordists] <<mai=
lto:>> wrote:



> Almost all the codec on the market (herein included the ones on the PC) r=
esample the signal so they cannot generate signal much over the audible ran=
ge.


Hmmm, in my personal experience most computer audio Interfaces (both extern=
al USB devices and even the onboard systems on the mainboards) that offer a=
 playback sample rate of 192 kHz can also generate ultrasounds up to over 8=
0 kHz. The frequency response may not be perfect, but it should work fine f=
or calibrating the frequency dial of analog heterodyne bat detectors.


I just tried it once again successfully on my Windows 10 Desktop PC that ha=
s an onboard "Realtec High Defition Audio" device....


Regards,

Raimund







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