PURPOSE: To obtain a polyphase modulation/demodulation circuit using surface acoustic wave element.
CONSTITUTION: A pulse signal generator 4 generates an impulse signal corresponding to the period of a transmission signal and changeover switches 51-54 switch and extract the impulse signal corresponding to the phase information of the transmission signal and the signal is inputted to input transducers 21-24 and a delayed surface acoustic wave stimulated by each transducer and propagated on a substrate is detected by an output transducer 3 in the polyphase modulation circuit, and the electrode finger structure of the input transducers 21-24 and the output transducer 3 is devised such that the impulse response between the input and output of the surface acoustic wave has a waveform of the burst pulse having the length of nearly period length of a transmission signal waveform and the polarity of the propagation path line or the electrode finger is varied so that the phase of the surface acoustic wave propagated through the input transducers 2124 and the output transducer 3 differs from each other.
ARAKI NOBUNARI
KOMINE KENJI
