A dual-channel voice-band PCM codec using Sigma Delta modulation technique
V. Friedman, D.M. Brinthaupt, D.-P. Chen, T.W. Deppa, J.P. Elward, E.M. Fields, Jeff W. Scott, T.R. Viswanathan · IEEE Journal of Solid-State Circuits · 1989
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.>