A dual-channel voice-band PCM codec using Sigma Delta modulation technique

A dual-channel sigma-delta ( Sigma Delta ) voice-band codec meeting AT&T/CCITT specifications is described. Its digital signal processing section has a bit-slice architecture which can be expanded to accommodate higher bit resolution. The active area per channel is 13 mm/sup 2/ in a 1.5- mu m CMOS process. It has only one power supply and the maximum power dissipation is 90 mW per channel. The crosstalk between channels is less than -71 dB. >

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