A 3-/spl mu/m CMOS Digital Codec with Programmable Echo Cancellation and Gain Setting

A 3-/spl mu/m CMOS digital signal processor (DSP) performs speech signal shaping, programmable echo cancellation and gain setting functions for telephone applications. A/D and D/A conversions are performed by making use of /spl Sigma//Spl Delta/ modulators, decimator, and interpolator filter blocks. In addition, the DSP acts as a control interface between the subscriber line interface circuit (SLIC) and the line card controller, the denouncing of eight line status bits included.