Pipelining of Cordic Based IIR Digital Filters

Cordic based IIR digital filters possess desirable properties for VLSI implementation such as local connection, regularity, and good finite word-length behavior, but can't be pipelined to finer levels (such as bit or multi-bit levels) due to the presence of feedback loops. In this paper, a pipelining method for the cordic based IIR digital filters is proposed using the constrained filter design methods and the polyphase decomposition technique. Using this method, the filter sample rate can be increased to any desired level. I. Introduction I N recent years, rapid advances in VLSI technology have had much impact on modern signal processing. Some of the desirable properties for VLSI realization are regularity, local connection and pipelinability. Orthogonal filters are digital IIR filters whose internal computation scheme consists of an orthogonal matrix transformation. The normalized lattice filter [1] and the scaled normalized lattice filter [2] are orthogonal filters in the sense tha..