Adaptive Differential Pulse Code Modulation

Synonyms:
  • Adaptive Delta Modulation
  • Adaptive Delta Pulse Code Modulation
  • ADPCM
  • Delta Pulse Code Modulation
German: Adaptive Differential-Puls-Code-Modulation
Japanese: 適応差分パルス符号変調

Communications engineering. An audio compression technique for digital transmission developed around 1970 in the Bell Laboratories. It is defined in the standards ITU-T G.726, G.711 and G.722 and is used for example in DECT.

This method transmits the difference between a predicted value and the signal as a 4- or 8-bit word. The prediction value is calculated from the preceding sampling values. The sampling step width is modified according to the fluctuation of the signal, so that a huge amplitude fluctuation leads to smaller steps and a small fluctuation to wider steps.

Belongs to:

Search for publications that include this term