Bandwidth conservation in digital transmission using class IV partial response signals

Considers an alternative technique of signalling in digital transmission aimed at increasing the operational data capacity per unit bandwidth through the utilisation of partial response (PR) signals. Partial response signalling utilises the so-called `functional intersymbol interference´ to reduce the transmission bandwidth required for the resulting data waveform. The reduction in bandwidth depends on the class of PR signals used: in the case of class 4 PR, the transmission bandwidth is equal to 50% of the minimum bandwidth defined by Nyquist. The paper discusses the spectral properties of PR signals and their possible utilisation in a spectrally efficient digital transmission system. Subject to the resolution of problems likely to arise in practical implementation, partial response signalling offers an exciting technique of achieving efficient frequency spectrum utilisation of particular interest in digital radio