Design of multiplier free FIR filters using a LADF sigma-delta (Σ-Δ) modulator

Sigma-delta (Sigma-Delta) modulators have been widely used over the last few decades, and one of their many applications has been in the field of FIR filter design. In this paper, we investigate the performance of multiplier free FIR filter design using the Look Ahead Decision Feedback (LADF) Sigma-Delta architecture. The LADF Sigma-Delta architecture, which has not been used in FIR filter design before, is compared with other conventional Sigma-Delta architectures. It will be shown that the LADF architecture has relatively low noise power at low frequencies and is preferable over the other modulators in the design of multiplier free FIR filter design. The selection of demodulator filters for reducing quantization noise due to the LADF Sigma-Delta architecture is also addressed in the paper. Using lowpass FIR filter design examples, the appropriate filter design methodology is presented in the paper.