Surface-Acoustic-Wave Multipath Combiner Development for Satellite Communication Receivers

A simple, inexpensive Surface Acoustic Wave (SAW) convolver based receiver was developed to implement a post detection integration multipath combining receiver to improve digital PSK communication through a multipath environment. High performance SAW convolvers are presently available as off-the-shelf components and these SAW devices provide the technology to extract multiple correlations from spread-spectrum signals to allow mitigation of multipath caused by frequency-selective fading. Bit error rate measurements were obtained for a fixed multipath channel and compared favorably with computer simulation performance predictions. A novel technique of using a Charge-Coupled-Device (CCD) time-base compressor to enable an off-the-shelf SAW convolver with 20 MHz band-width and 16 us delay to be used to match filter over a 100 us window was demonstrated. This study has demonstrated, via a breadboard prototype, the feasibility of performing multipath combining with off-the-shelf SAW devices.