Pulses satisfying the Nyquist criterion

Pulses having zero intersymbol interference are necessary in data communications systems of various types. The requirement is that a bandlimited pulse p(t) is such that p(nT)=0, n not=0, and the well known cosine rolloff pulse is widely used in this context. The author presents a closed-form time-domain expression for generating all such pulses satisfying the Nyquist criterion, and demonstrates that pulses exist which are superior to the cosine rolloff in terms of sensitivity to timing error.