Design and implementation of IIR filters in STLC7545 analog front-end for voice communication

We present a design method for the synthesis of infinite impulse response (IIR) filters embedded in the enhanced V.34 analog front-end chip STLC7545 for voice communication. The chip provides a powerful solution for the implementation of several high-speed modems. Each IIR filter is designed as a cascade of second-order quadratic sections. A procedure for scaling the amplitude and representing the coefficients of these filters in fixed point format is then presented. Extensive numerical simulations have been carried out and the viability of the design method is justified by successful implementation of these filters on the hardware.