>I want an inexpensive way to connect a hydrophone to a
>PC such as to the RCA mic jack of a laptop or a PCMCIA
>card. I will then write the software to read the
>audio-in port. I want to read frequencies between 1 Hz
>and 100 kHz and use my own software to read the input
>port. I already have the FFT and other signal
>processing completed.
>
>Does this make sense? For example, isn't the typical
>mic port build for the frequencies of the human audio
>range or can it accept a wider range? If I need a
>PCMCIA card or some other interface for the A/D then
>which one would you recommend?
Yes, the mic/line-in port on most sound cards has a maximum sampling rate
of 48 kHz, so the maximum frequency it can capture is half that or less.
Typically you see good frequency response up to 20-22 kHz.
To get higher frequencies, you need a more specialized data acquisition
card. I've used National Instruments cards with success, specifically the
DAQCard 6062-E, which is a PC card (PCMCIA card), and the PC6071-E, which
is a PCI board. These should give you single-channel input at the
frequencies you need.
You may also want to try out Ishmael, which can record sound onto disk
according to a schedule you set up, display real-time spectrograms, detect
calls, localize calls, and a host of other tasks. It can interface to the
above NI cards as well as some other cards. It's freely available at
<a href="http://cetus.pmel.noaa.gov/cgi-bin/MobySoft.pl";
rel="nofollow">http://cetus.pmel.noaa.gov/cgi-bin/MobySoft.pl</a> .
>Which hydrophone(s) do you recommend?
I'd suggest looking at Joe Blue's hydrophone page. You can find it via the
"Equipment" link on the ASA Bioacoustics site,
<a href="http://cetus.pmel.noaa.gov/Bioacoustics.html";
rel="nofollow">http://cetus.pmel.noaa.gov/Bioacoustics.html</a> .
Hope this helps,
Dave Mellinger
[EMAIL PROTECTED]
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