A helicoidal guide surface wave convolver

摘要

PURPOSE:To suppress the self-convolution signal without remarkable modification of a conventional surface acoustic wave SAW convolver structure by providing a sub-electrode between a gate electrode and each input electrode and applying a bias voltage to the sub electrode so as to bring the semiconductor layer thereunder into the inverting state. CONSTITUTION:Two sub electrodes 14 are placed between the gate electrode 13 and an interdigital electrode 12 and on the propagation path of a surface acoustic wave and a bias voltage is impressed from a DC bias source 15 to the sub electrodes. The bias voltage is selected to a value in such a way that the semiconductor layer side is inverted at the border between the insulator layer 10 under the sub electrodes 14 and the semiconductor layer 11. Since the semiconductor layer under the sub electrodes is in the inverting state, a surface acoustic wave stimulated by an input signal is slightly attenuated and its reflected wave is attenuated considerably, a convolution signal is reduced.