A 32 kbit/s ADPCM algorithm having high performance for both voice and 9.6 kbit/s modem signals

A description is given of an advanced 32-kb/s ADPCM (adaptive digital pulse code modulation) algorithm and its implementation in a single-chip custom LSI using 2- mu m CMOS technology. The performance of the proposed codec, in terms of voice and modems operating at 1200-9600 b/s, is also discussed. The results indicate that the codec provides speech quality equivalent to that of the CCITT G.721 ADPCM and is capable of transmitting V.23 1200 b/s and V.27 and V.29 4800 b/s signals over at least four asynchronous tandem links. It can also transmit V.29 modem signals at 7200 b/s over at least four and at 9600 b/s over two asynchronous tandem links, and V.32 signals at 9600 b/s over four asynchronous tandem links.<
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