| 摘要 |
PURPOSE: To establish correlation between a reception signal and a PN code in a short time by controlling a timing to decide a head position of the PN code based on an AC power supply generating an AC signal, a time signal and a zero-cross point. CONSTITUTION: When an error is between timers 9, 14 of a transmission station 1 and a reception station 2, a PN code is outputted to a demodulator 10 based on an AC power supplies 8, 14 generating an AC signal, a time signal generated by the timers 9, 15 and a zero-cross point. Then the PN code is outputted while matching a head of the PN code to the zero-cross point sequentially and a correlation peak is detected at a zero-cross point when that of the PN code of the reception station 2 is coincident with the zero-cross point of the transmission station 1, a timing when the PN code is outputted is fixed and the code is demodulated by a demodulator 10. Since the transmission start time is set for each prescribed time and the correlation processing of the PN code is conducted based on the time of the zero-cross point, the components are simplified. Furthermore, the time signal generated by the power supply 14 and the timer 15 is used by the demodulator 10 to demodulate a signal and to control a timing to decide the head position of the PN code. |
