Electronic – ADC Question for Sampling With Electret

adcaudiomicrophone

I am a bit confused when looking at ADC's for my project. I am using an electret microphone and modifying the circuit at the bottom of page 15 here (I can't input the image itself unfortunately here):
http://www.en-genius.net/includes/files/avt_030110.pdf

enter image description here

I'd like to sample audio at ~12KHz, though this will change depending on applications I'm using (testing out voice recognition). I'm going for a bit depth of 16, as the input volume will vary and probably be from quite different environments and distances.

With background supplied, I wonder if an audio specific ADC is really necessary? Example is here

I don't need stereo, only mono. These seem to be more for more robust recording and/or output situations than my application, correct? All I need is a mic input, and the amplification would already be done by the circuit I mentioned.

Also, given these values, would I simply need ~12ksps to match the 12khz sampling frequency?

Would a simple ADC that has correct resolution and SPS be fine then, supposing more of the DSP and amplification would be done elsewhere? Is there something special about audio ADC's that behaves quite differently?

Thanks for your help, I know some of these are quite elementary inquiries, though I haven't found very clear answers to them. I could be looking in the completely wrong route, so any input is highly appreciated.

Best Answer

Math of sampling dictates two things:

  1. You need to sample twice as fast (in the ideal, practically faster) as the maximum frequency you'd like to capture
  2. You need to remove frequencies above half the sample rate with a low-pass filter, or they will corrupt your lower frequency content through aliasing.

If you need 12 kHz, you need to sample at more than 24 kHz and provide an anti-aliasing filter before the sample is done.

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