Patent ID: 7647059

Claim:
A communication system for performing radio communication, the system comprising: a transmitter including: a code spreader for performing code spreading on data to be transmitted; a transmitting-end synchronizing signal generator for generating a plurality of transmitting-end synchronizing signals with different phases on which the timing of the outputting of a radio signal of a single cycle pulse is based; a transmitting-end synchronizing signal selector for selecting one of the plurality of transmitting-end synchronizing signals on the basis of the code-spread data to be transmitted; and a transmitting-end signal output unit for outputting the radio signal of the single cycle pulse at timing of synchronization with the selected transmitting-end synchronizing signal; and a receiver including: a code output unit for outputting a despreading code for performing despreading on the radio signal; a receiving-end synchronizing signal generator for generating a plurality of receiving-end synchronizing signals which are the same as the plurality of transmitting-end synchronizing signals; a receiving-end synchronizing signal selector for selecting one of the plurality of receiving-end synchronizing signals on the basis of the despreading code; a receiving-end signal output unit for outputting a correlation-detected signal of a single cycle pulse with which the correlation of the radio signal is detected at timing of synchronization with the selected receiving-end synchronizing signal; and a correlator for detecting a correlation between the radio signal and the correlation-detected signal; and a convolver for performing code spreading on the data to be transmitted and detecting a correlation between the radio signal transmitted from the transmitter and the correlation-detected signal outputted from the receiving-end signal output unit, the convolver including: a semiconductor on which conductive regions are formed like stripes perpendicularly to a direction in which a surface acoustic wave travels; an electrode for converting an electrical signal provided to a surface of the semiconductor into the surface acoustic wave; and an integrator for integrating the sum total of the products of voltage applied to the conductive regions and the surface acoustic wave which passes through the conductive regions over a certain period of time, and for outputting a result.