The Free On-line Dictionary of Computing (30 December 2018):

Pulse Code Modulation

    (PCM) A method by which an audio signal is represented
   as digital data.

   Virtually all digital audio systems use PCM, including, CD,
   DAT, F1 format, 1630 format, DASH, DCC, and MD.  Many people
   get confused because "PCM" is also slang for Sony's F1 format
   which stores PCM digital audio on videotape.

   (1995-02-09)