SPREAD SPECTRUM COMMUNICATION EQUIPMENT, SURFACE ACOUSTIC WAVE ELEMENT AND SURFACE ACOUSTIC WAVE PARTS

摘要

PROBLEM TO BE SOLVED: To perform demodulation in a simple configuration by demodulating the source data of in-phase component and orthogonal component from 1st and 2nd adder circuits, composing a correlative value possession circuit of a surface acoustic wave(SAW) matched filter and composing a delay circuit of a SAW delay line. SOLUTION: Concerning a SAW matched filter 20, the number of pairs of interdigital electrodes corresponding to respective codes is more than one in comparison with the number of coded electrodes 22 for input. Thus, efficiency for converting input signals to SAW at the electrodes 22 can be improved and output efficiency at interdigital electrodes 23 is made high. Delay quantity T1 of a SAW delay line 26 is set to the time difference of T+(±n×2/8)/fc between an input signal from the delay line 26 and an input signal from the filter 20 at the input time of the adder circuit. Delay quantity T2 of a SAW delay line 32 is set to a value so as to delay an input signal from the delay line 32 rather than the input signal from the filter 20 just for the time of T+(±m-5xa/8)fc at the input time of the adder circuit.