pulse-code modulation

Also known as PCM, pulse code modulation

digital representation of sampled analog signals

Key facts

Filename extension: .L16, .WAV, .AIFF, .AU, .PCM
Internet media type: audio/L16, audio/L8, audio/L20, audio/L24
Type code: "AIFF" for L16, none
Magic number: Varies
Type of format: Uncompressed audio
Contained by: Audio CD , AES3 , WAV , AIFF , AU , M2TS , VOB , and many others
Open format: Yes
Free format: Yes

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Commons category: Pulse-code modulation
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Article

Pulse-code modulation (PCM) is a method used to digitally represent analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications. In a PCM stream, the amplitude of the analog signal is sampled at uniform intervals, and each sample is quantized to the nearest value within a range of digital steps. Claude Shannon, Bernard Oliver, and John Pierce were inducted into the National Inventors Hall of Fame for their PCM patent granted in 1952.

Linear pulse-code modulation (LPCM) is a specific type of PCM in which the quantization levels are linearly uniform. This is in contrast to PCM encodings in which quantization levels vary as a function of amplitude (as with the A-law algorithm or the μ-law algorithm). Though PCM is a more general term, it is often used to describe data encoded as LPCM.