A Square-Root Nyquist (M) Filter Design for Digital Communication Systems

Designing matched transmit and receive filters whose combination satisfies the Nyquist condition is a classical problem in digital communication systems. In this correspondence, we propose a novel method for designing such filters. The proposed method is based on a cost function whose minimization leads to designs that can strike a balance between the stopband attenuation, the residual intersymbol interference (ISI), robust sensitivity to timing jitter, and/or reduced peak-to-average power ratio (PAR). An iterative algorithm for optimizing the proposed cost function is suggested and its excellent performance is shown by presenting a variety of design examples. Compared to the published works, the proposed method offers the following unique advantages. By introducing a symmetry in the filter coefficients, filters with reduced computational complexity can be designed. We also introduce a design parameter that allows one to strike a balance between the PAR and other features of the desired filter.