ISI-free pulses produced by improved Nyquist filter with piece-wise linear characteristic

A family of improved Nyquist filters with a piece-wise rectangular frequency characteristic composed of six nonzero linear segments with variable-length projections onto the frequency axis is investigated. They produce a family of inter-symbol interference-free (ISI-free) pulses with an asymptotic decay rate of t^-2 that shows comparable or better inter-symbol interference performance, compared with some recently proposed pulses. The co-ordinates of the points that delimit the linear segments are varied in a limited interval in order to obtain a minimum value of the probability of error when the impulse response is sampled with a small time offset. The results outperform previously reported pulses taken as a reference.