A Comparison of Double Convex and Double Concave Improved Nyquist Filters

Abstract

This paper presents a comparative analysis of two families of improved Nyquist filters with a piece-wise parabolic frequency characteristic. Their construction is based on a novel approach and produces ISI-free pulses that shows comparable or better ISI performance in the presence of sampling errors, as compared with some recently proposed pulses. The coordinates of the junction points that delimit the parabolic pieces were determined in order to produce a minimal value of the error probability when the impulse response is sampled with a fixed time offset that accounts for the imperfect synchronization in the receiver. With a minor exception both families outperform the poly filter, so far considered the best one.

Keywords

• error probability
• filters
• Fourier transforms
• pulse generation
• transient response