Hi all, Is it possible to use the mic input of a pc to capture an analog signal and convert it into digital signal using the voide processing circuit of the PC?I browsed the net and asked the question in arch.embedded but I did not get any specific answer.Is it not possible to convert analog signals of frequency other than the voice frequency into digital form?
thanks in advance. Krishna.V.J
That's basically what happens when you record a .wav file
I browsed the net and asked the question
depends very much on what sound card you have. Most of them I suspect go up to about 20KHz since thats all you need for the human hearing range.
There are quite a few software packages out there that allow you to use the mic or line in of your sound card as a rudimentary oscilloscope or data logger.. which I suspect is something you are trying to do, but I wouldnt expect it to have a very wide range, or cope with DC voltages.
Mark
yes, not DC but an AC wave can be captured and analyzed via a few forms. Sine Wave crossing, DFT, FFT etc... the first basic step is to learn how to code so that you can actually get your sound card to switch into record mode and pass to your application the blocks of samples the sound system is collecting which is put in PCM (Pulse coded Modulation) format.
-- Real Programmers Do things like this. http://webpages.charter.net/jamie_5
yes for AC signals. no for DC (and below about 20Hz)
about 20Hz to 20000Hz (voice is normally considered 300-3300)
-- Bye. Jasen
The answer is yes if your signal you have and/ot part you are interrested in is within the sound card supported frequency range. generally frequencies from few hundred Hz to few kHz be recorded more or less at useable quality on mic input but the frequency response might not be flat (outside this the signals the signal ca attenuate considerably).
When usign line input you generally get around 20 Hz to 20 kHz with pretty flat frequency response.
Soundcards are not detected to handle frequencies outside normal audio frequencies (20 Hz to 20 kHz). Those higher and lower frequencies are intentionally filtered out on soundcard circuitry before actual analogue to digital conversion.
With some hardware modifications at least some sound cards can be adapted to accept frequencies down to DC: Sound card based multimeter
-- Tomi Engdahl (http://www.iki.fi/then/) Take a look at my electronics web links and documents at http://www.epanorama.net/
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