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ADPCM (Adaptive Differential Pulse Code Modulation)
Note: Many topics at this site are reduced versions of the text in "The Encyclopedia of Networking and Telecommunications." Search results will not be as extensive as a search of the book's CD-ROM.
ADPCM is a more efficient version of the digitizing method called PCM (pulse code modulation). It converts analog signals to digital data and is used to transmit analog voice over digital channels. Organizations that establish digital lines between remote sites can transmit both voice and data over these lines by digitizing the voice signals before transmitting. ADPCM uses a lower bit rate than normal PCM, which permits more voice channels to be transmitted over a typical digital line. The difference between samples is used and the coding scale can be dynamically changed to compensate for amplitude and frequency variations.
Copyright (c) 2001 Tom Sheldon and Big Sur Multimedia.