Abstract: There is disclosed a synchronous circuit and a receiver in which a long code for use in communication can be determined in a short time, and circuit scale can be reduced. Upon receiving input of a data stop signal from a control unit, a matched filter continues to hold the signal held at the time, performs a product sum operation of a spreading code successively inputted from a spreading code generator and the held signal, and successively outputs correlation signals in the synchronous circuit and the receiver.

Abstract: There is disclosed a correlation circuit for spread spectrum communication which reduces the number of constituting elements to attain low power consumption and which can obtain correlation in a short time, to solve a problem that a conventional sliding correlator requires much time to obtain the correlation and that a matched filter increases the power consumption. In the spread spectrum communication correlation circuit, an A/D converter converts a received spread spectrum signal to a digital signal. Under control of a controller, one symbol of signals are written to an S/H circuit with a 16 MHz. clock, shifted for each sample and read to a high-speed correlator from the S/H circuit with a high-speed clock of 1.6 GHz a plurality of times, and the high-speed correlator performs a product sum operation with a spread code with the 1.6 GHz clock. At the same time the reading is performed, the next symbol of signals are written to the S/H circuit.

Abstract: In a conventional correlation circuit for spread spectrum communication, when a sliding correlator is used, much time is required. When a matched filter is used, a problem is that a circuit scale and power consumption are increased. In the present invention, however, there is provided a correlation circuit for spread spectrum communication which minimizes the number of constituting elements, and can reduce the power consumption. In the correlation circuit for spread spectrum communication of the present invention, a spread spectrum received signal is A/D converted and accumulated in a data memory unit by a symbol unit, data rate is converted, and a high-rate MF performs a product sum operation processing at a high rate so that a correlation output is obtained.