Memory Correlators with Multiple Input Channels

Abstract

Absfmct-The design of acoustoelectric memory correlators with several input channels is described. Channel isolation is provided by holographic phase cancellation of angularly offset beams. An analysis is given of the cross correlation between wide-band signals on adjacent beams, which are aperture-profiled to improve the isolation. Beam-protiling is obtained by a combination of a multistrip fan-out structure and an interdigital transducer. The factors contributing to the power efficiency and its frequency dependence are analyzed in some detail. The design and experimental results obtained with an eight-channel device with a 40-MHz bandwidth and a 6.5-ps delay in each channel are presented. The experimental work used a separated-medium configuration with Schottky diodes on silicon that was coupled capacitively to a surface-acoustic-wave lithium-niobate delay line through an air gap.