SURFACE ACOUSTIC WAVE MATCHED FILTER

摘要

An output side electrode of a surface acoustic wave matched filter has portions having different delay times between taps. Said parts of the output side electrode having different delay times between taps may be provided by arranging parallelly a plurality of output side electrodes 13a and 13b having different scales or different tap distances, or by forming output side electrodes in an inclined fashion or in a dog-leg shape viewed in a direction of an aperture length, or by arranging, between electrode fingers, thin films having different dimensions or thicknesses viewed in the direction of the aperture length, or by forming, between electrode fingers, recessed portions having different dimension or depth viewed in the direction of the aperture length. In the surface acoustic wave matched filter for use in a spread spectrum communication, it is possible to prevent a decrease in a correlation caused by a variation in a propagating velocity of a surface acoustic wave due to a temperature characteristic as well as by fluctuations in the propagating velocity for respective substrates or within a single substrate. <IMAGE>