At 06:59 AM 12/29/2003 -0500, serge masse <[EMAIL PROTECTED]> wrote: >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 http://cetus.pmel.noaa.gov/cgi-bin/MobySoft.pl . >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, http://cetus.pmel.noaa.gov/Bioacoustics.html . Hope this helps, Dave Mellinger [EMAIL PROTECTED]
