Sub-Optimum Receiver Filters

Abstract

This paper presents a method for analyzing the performance of a digital receiver when using standard analog filters in place of the ideal matched filter. Expressions are developed for the probability of error and performance loss of the sub-optimum receiver as functions of the minimum eye value and noise bandwidth of the suboptimum receiver filter. A method is developed for choosing the best sub-optimum filter in the sense of minimizing the probability of error. The best sub-optimum Bessel filter of order less than or equal to 6 is specified in terms of 3-dB bandwidth and filter order for a system with a rectangular transmit pulse. This method is applicable to other transmit pulse shapes and can be applied to channels with limited bandwidth. The optimum 3-dB bandwidth obtained here can be scaled relative to the symbol rate to correspond to any practical system.