Multichannel surface acoustic wave encoder/decoder

摘要

A multichannel surface acoustic wave encoder/decoder having a common electrical input is designed so that the insertion losses of the channels differ despite the apparent design constraint of closely matched channel output impedances. The input transducing device or SAW transmitter is divided into individual transducers (or into subtransducers) having different numbers of finger overlaps, thus achieving different acoustic output levels which in turn result in different insertion losses for different channels. The finger spacing of the SAW transmitters can differ between the respective input transducers or subtransducers so as to optimize the center frequency of each channel.