High-speed VLSI state-space orthogonal IIR digital filters using matrix lookahead

Abstract

The increasing demands for multimedia and wireless communication applications have had much impact on design of high-speed and low-power modern DSP systems. Orthogonal IIR digital filters can achieve a sharp transition band and have good finite word-length behavior and are used in many modern DSP applications such as mobile communications. However, Cordic-based fine-grain pipelined true orthogonal IIR digital filters have not been developed so far. A state-space-based novel algorithm for designing fine-grain pipelined true orthogonal IIR digital filters is proposed using the matrix lookahead technique. The algorithm only involves applying orthogonal transformations that are known to be numerically very reliable, and therefore is ideal for VLSI implementations. The proposed filter architecture can be operated at arbitrarily high sample rates and achieves linear increase in hardware complexity with respect to the filter order and pipelining level. It consists of only Givens rotations which can be mapped onto Cordic arithmetic-based processors. Finally, an intermediate frequency filter for the USA mobile telephone system is designed using the proposed orthogonal filter synthesis algorithm.