To improve the transmission speed by conducting spread spectrum coding with a matched timing in a composite communication channel consisting of a plurality of communication channels whose carrier frequency differs.
A frequency spread modulator 4-1 converts an information data series 3-1 to be sent into a spread spectrum signal 7-1 of a base band by using a spread code series 6-1 from a PN code generator 5. A frequency conversion modulator 8-1 receives a carrier frequency f1 specific to a communication channel from a local oscillator 9-11 and modulates it by using the spread spectrum signal 7-1 and provides an output of the modulated signal via a filter 11-1. A signal multiplexer 13 multiplexes spread spectrum signals 12-1-12-n of each communication channel on a frequency base and sends the result to a communication channel. Each of communication channel modulators 4-1-4-n applies spread spectrum processing to the information data series 3-1-3-n in a matched timing.
SHINONAGA HIDEYUKI
KOBAYASHI HIDEO
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