Analog to Digital Conversion

• A ``real-world'' signal is captured using a microphone which has a diaphragm that is pushed back and forth according to the compression and rarefaction of the sounding pressure waveform.
• The microphone transforms this displacement into a time-varying voltage--an analog (continuous-time) electrical signal.
• The process by which an analog signal is digitized is called analog-to-digital or ``a-to-d'' conversion
  • conversion is done using hardware called an analog-to-digital converter (ADC).
• In order to properly represent the electrical signal within the computer, the ADC must accomplish two tasks:
  1. sampling: digitize the time variable $t$;
  2. quantization: digitize the instantaneous amplitude of the pressure variable $x(t)$.