PCM stands for Pulse Code Modulation. PCM technology is a means by which standard audio signals (which are represented by waveforms) are converted to digital audio signals (which are represented by 1's and 0's - much like computer data) with little, or no, compression. The method of audio conversion is used on most digital audio formats, including CDs and DVD-Audio, and is also used to some extent in Blu-ray and HD-DVD applications. The PCM signal is converted back to analog form for distribution to loudspeakers.
PCM, although digital in nature, should not be confused with a Dolby Digital or DTS Bitstream, which is compressed, and digitally encoded in a different manner than PCM. However, Dolby Digital and DTS encoded audio signals can be decoded into PCM signals and transferred via HDMI to a growing number of Home Theater Receivers for further processing and amplification. This is common in most Blu-ray and HD-DVD player applications. See also: Bitstream.
Also Known As: Pulse Code Modulation, LPCM