ISI-free pulse shaping filters for receivers with or without a matched filter

We present a design procedure to obtain pulse shaping filters which result intersymbol interference (ISI) free transmit signals as well as matched filtered received signals. Such kind of pulse shaping filters presents flexibility in the design of the receiver systems. The design procedure results symmetric filters as opposed to the filters proposed in previous works. Design parameters can be used to trade the stopband attenuation or fast decay in time for doubly ISI-free property. The performence of the filters is tested in a V26ter modem in comparison with the standard raised-cosine filters. Both filters have almost identical performances in terms of MSE at the equalizer input.