A differential phase shift keying convolver having a plurality of tracks includes at least one track where an opposite phase convolution output is produced. Each track includes two output gates spaced at the center for differential phase shift keying demodulation. Among these output gates, some gates selected in accordance with the phase relationship between convolution outputs are connected to provide sum and/or difference outputs of the convolution signals. The opposite phase convolution outputs can be produced by arranging at least one of the input transducers in a step-like configuration, by using multistrip couplers, or by providing a metal film in a selected position of the traveling path of surface acoustic waves for application of a control voltage.