Pulse-shaping filters for digital transmission systems

Different types of digital pulse-shaping filters providing zero intersymbol interference (ISI) in digital transmission systems are examined. The emphasis is on matched transmit-receive filter pairs satisfying the Nyquist criterion. Several finite impulse response (FIR) filter design techniques are discussed. Depending on the application, the stopband attenuation can be minimized either in the minimax or in the least-mean-square sense. A class of transmit-receive filter pairs based on the use of a special type of infinite impulse response (IIR) filters is introduced. It is shown that this filter class includes matched pairs in which both the transmit filter alone and the pair have very low ISI. Computationally efficient multistage designs are considered. Different FIR and IIR Nyquist filter designs are illustrated