A PCM voice codec with on-chip filters
J.T. Caves, S.D. Rosenbaum, L. Sellars, C.H. Chan, J. Terry · IEEE Journal of Solid-State Circuits · 1979
Describes a monolithic NMOS coder/decoder (codec) with associated CCD transversal minimum phase filters which has been successfully implemented. The codec operates by charge redistribution in a binary-weighted capacitor array, with a resistor chain to define individual steps. The experimental performance compares well with PCM codecs implemented with discrete components.