AnL1‐Approximation for the Design of FIR Digital Filters with Complex Coefficients
Ikuya Murakami, Yukio Mori, Naoyuki Aikawa · Electronics and Communications in Japan · 2015
SUMMARY In this paper, we propose anL1‐approximation for the design of FIR digital filters with complex coefficients. TheL1‐approximation has the advantage of having a flatter passband and a small overshoot around the discontinuity point as compared with theL2‐approximation and ‐approximation. As the obtained filter has complex coefficients, it is possible to reduce group delay and to design a digital filter with a asymmetric amplitude characteristic with respect to the origin. The algorithm proposed in this paper is based on Newton's method, which is an efficient iterative approximation algorithm. We show the effectiveness of the proposed method through a design example.