A voice compression technique that encodes the changes (i.e., deltas) in the slope (i.e., rate of change), rather than the amplitude, of analog voice signals. CVSD yield compression ratios of 4:1 (16 kbps) or 8:1 (9.6 kbps), as compared to pulse code modulation (PCM) at 64 kbps.Although CVSDM has given way to techniques such as adaptive differential pulse code modulation (ADPCM) in contemporary voice networks, it is used in Bluetooth voice applications. See also ADPCM, Bluetooth, compression, encode, and PCM.