Fast signal processor encodes 48 kHz/16-bit audio into 3-bit in real time

A real-time implementation of a source coding method allowing bit rate reduction from 16 bits to 3 bits per sample at sampling rates up to 48 kHz is described. Using an adaptive transform coding technique optimized for low computing complexity and a system based on the AT&T DSP 32 single-chip signal processor, a very good compromise between sound quality and hardware complexity has been achieved. Distortions were audible only by trained listeners for critical pieces of music. One signal-processor module is needed for each of the two coders and decoders. Each one fits on a single-height Eurocard.