'''Pulse-code modulation''' ('''PCM''') is a method used to [[Digital signal (signal processing)|digitally]] represent [[analog signal]]s. The PCM methodIt is the standard form of [[digital audio]] in computers, [[compact disc]]s, [[digital telephony]] and other digital audio applications. In a PCM [[Stream (computing)|stream]], the [[amplitude]] of the analog signal is [[Sampling (signal processing)|sampled]] at uniform intervals, and each sample is [[Quantization (signal processing)|quantisizedquantized]] to the nearest value within a range of digital steps.
'''Linear pulse-code modulation''' ('''LPCM''') is a specific type of PCM methodin whereinwhich the quantization levels are uniformlylinearly linearuniform.<ref name="LOC_LPCM" /> This uniform encoding is in contrast to PCM encodings whereinin thewhich quantization levels of quantization vary as a function of amplitude,e.g.(as with the [[A-law|A-law algorithm]] andor the [[μ-law|μ-law algorithm]]). AlthoughThough a''PCM'' general,is technicala usage,more thegeneral term, ''PCM''it alsois isoften used to describe data encoded as LPCM.
A PCM stream has two basic properties that determine the stream's fidelity to the original analog signal: (i) the [[sampling rate]], which is the number of times per second that samples are taken; and (ii) the [[Audio bit depth|bit depth]], which determines the number of possible digital values that can be used to represent each sample.
