Multipath outage performance of digital radio receivers using finite-tap adaptive equalizers

An attempt is made to determine how many taps are needed to approximate ideal performance in finite tap delay line equalizers. An M-level quadrature amplitude modulation system using cosine rolloff spectral shaping and an adaptive equalizer with either fractionally spaced or synchronously spaced taps are assumed. It is found that, for the assumed multipath fading model, very few taps are needed to approximate the performance of an ideal infinite-tap equalizer.