Skip to Main Content
A general criterion is derived that must be satisfied by the frequency characteristic of a transmission channel if a recovered f.s.k. signal is to exhibit zero i.s.i. It is shown that the bandwidth over which nonzero transmission is required is at least three times the Nyquist bandwidth for the given signalling rate, except for the special case of a frequency shift equal to the signalling rate. A minimal-bandwidth solution is given for a symmetrical bandpass channel of small fractional bandwidth.