Dictionary.com
Thesaurus.com

A/D converter

Scientific  
  1. Short for analog to digital converter. An electronic device that takes a voltage source as an input, and yields a digital numerical output indicating the strength of the voltage at the source. A/D converters are used in digital recording devices, in which an audio signal in an electronic circuit (as picked up by a microphone) is digitized and recorded on disk or tape.

  2. Compare D/A converter