Matsushita Electric Industrial Co., Ltd.

Masatoshi Ohtsuka

Naoki Koga

Seishi Tomari

A spread spectrum communication apparatus includes at least one surface acoustic wave matched filter, a plurality of surface acoustic wave delay lines having different delay amounts, and integrating circuits for integrating an output signal of the surface acoustic wave matched filter and the respective output signals of the plurality of surface acoustic wave delay lines.

Spread spectrum communication apparatus, and demodulator, surface acoustic wave element and surface acoustic wave parts for spread spectrum communication

A spread spectrum demodulation circuit includes a correlation signal generator which generates a correlation signal from a reception signal to which a quadrature phase shift keying and a spread spectrum modulation are performed. First and second delay elements have different delay times, and delay the correlation signal to obtain first and second delay signals, respectively. First and second adders add the correlation signal and the first and second delay signals to obtain first and second addition signals, respectively. First and second distributors distribute the first and second addition signals, respectively. First and second multiplication circuits obtain first and second multiplication signals from distributed signals inputted from the first and second distributors, respectively. A data demodulation circuit demodulates the first and second multiplication signals to recover a transmission information signal.

Spread spectrum demodulation circuit, spread spectrum communication apparatus, delay-detection-type demodulation circuit, and delay-detection-type communication apparatus

A spread spectrum communication apparatus employs a surface acoustic wave matched filter and surface acoustic wave delay lines which enables the demodulation in accordance with the QPSK scheme. A SS demodulator has a correlated signal acquisition circuit for demodulating a received SS signal to acquire a correlated signal, first and second delay circuits for delaying an output signal from the correlated signal acquisition circuit, and first and second adder circuits for adding the output signal of the correlated signal acquisition circuit and respective outputs of the first and second delay circuits. The first delay circuit delays the input signal by T+(.+-.n+5.times.a/8)/fc, while the second delay circuit delays the input signal by T+(.+-.m-5.times.a/8)/fc. Thereby, a spread spectrum communication apparatus which enables the demodulation in accordance with the QPSK scheme by a simple configuration using a surface acoustic wave matched filter and surface acoustic wave delay lines is provided.

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Fukuoka, Japan

Masatoshi Ohtsuka