Adaptive differential pcm coding.

摘要: An ADPCM coder (100) converts a linear PCM input signal representative of encoded speech or voiceband data into quantized n-bit differential output signal. Samples the are delivered to difference circuit (11) along with estimate same derived from an adaptive predictor (12). The resultant is coupled dynamic locking quantizer (DLQ). A version said algebraic adder (17) where it algebraically added estimate. result this addition predictor, which in response thereto serves generate next for comparison sample. has two speeds adaptation, namely, fast speed adaptation when represents and very slow (almost constant) tone signals. decoder (101) operation essentially inverse coder, similarly adaptation.