Spectrum spread communication system

摘要

Disclosed is a spectrum spread communication system which is hardly influenced by noises, and in which a frame structure can be identified at a receiving side without use of a frame synchronization signal. A spread code generator switches spread codes (“Scai” and “Scbi”) in each frame, and outputs it to a spread modulation unit. The spread modulation unit performs spread modulation of transmission data, and transmits it to a direct current power line. A reference code generator generates reference codes (“Scai” and “Scbi”) in the same code phase. Spread demodulation units performs spread demodulation of the received signal with use of the reference codes (“Scai” and “Scbi”), and output it to a selection unit. A frame synchronization detection unit identifies a frame structure on the basis of switching of a synchronization state of a code phase in a code phase synchronization detection unit. The selection unit outputs reception data by selecting spread demodulated data from the spread demodulation unit which is in a phase-synchronized state.

主权项

1. A spectrum spread communication system comprising:
a communication base unit which communicates with communication extension units, wherein: each of the communication extension units has: a spread code generator which switches and selectively outputs spread codes in each frame; and a spread modulation unit which performs spread modulation of frame-structured transmission data by using the spread codes from the spread code generator, and transmits a spread-modulated signal to a transmission line; and the communication base unit has: a reference code generating unit which generates a plurality of reference codes corresponding to the plurality of spread codes; spread demodulation units in respective spread demodulation systems, the spread demodulation units performing spread demodulation of the spread-modulated signal received via the transmission line by using the reference codes; a code phase synchronization detection unit which controls the phase of the reference codes from the reference code generating unit so that the spread-modulated signal is synchronized in phase with any one of the reference codes; a frame synchronization detection unit which outputs a frame synchronization signal on the basis of timing of switching from a state in which the spread-modulated signal is synchronous with one reference code, to a state in which the spread-modulated signal is synchronous with another reference code; and a selection unit which selectively outputs, on the basis of the frame synchronization signal, signals demodulated by the spread demodulation units.