A two chip PCM voice CODEC with filters
Y.A. Haque, Roubik Gregorian, R.W. Blasco, Ruishi Mao, W.E. Nicholson · IEEE Journal of Solid-State Circuits · 1979
Architecture and design of a monolithic voice CODEC is described. The CODEC consists of 2 chips-the transmit chip includes the companding coder (nonlinear A/D) along with filtering functions, and the receive chip consists of the expanding decoder (nonlinear D/A) chip with its smoothing filter. Experimental results show the circuit to meet accepted requirements.