A SAW planar piezoelectric convolver

An increase of the dynamic range of a surface-wave piezo-electric convolver can be obtained by increasing its bilinear factor. We show that this can be done by reducing the acoustic beamwidth in the interaction region. A lower limit of beamwidth is found through the study of the guided modes in the convolver plate. A 600-BT product device using nonsymmetrical couplers to obtain the beamwidth reduction is described. The main characteristics-bandwidth, dynamic range, spurious signals-are given and we show a linear FM pulse autocorrelation performed in this device.