Analog to Digital Conversion
Steve Rowe (test lead on the sound team) points to a great article from Ars Technica on D2A:
If you want digital audio in a computer, you have to get it from somewhere. Usually that means taking analog sound out of the air and turning it into the bits that a computer can understand. Ars Technica gives us another installment of the AudioFile. This one covers the subject of Analog to Digital Conversion.
Well worth reading.