| 摘要 |
PURPOSE:To attain narmally signal transmission even if the transmission loss of a power line at signal transmission is considerably large at a specific frequency by using the spread spectrum communication system in a power line carrier system. CONSTITUTION:An M-series code outputted from an M-series code oscillating circuit 9 in a transmission unit 4 is a signal having almost uniform spectrum, and a mixer 11 spread the spectrum of an A1 wave outputted from a carrier wave oscillating circuit 10 by modulating the wave with the M-series code by the PSK system and transmits the modulated result to a power line via a buffer 12. A synchronizing signal generating circuit 21 detects a zero cross signal of an AC power supply voltage on the power line as a synchronizing signal. A high frequency signal is amplified at a high frequency amplifier 15 in the receiving unit, a mixer 16 performs correlating detection with an output of an M system code oscillating circuit 17 and the information included in the original A1 wave is obtained via a detecting circuit 18 and an output circuit 19. |
