| 摘要 |
PURPOSE:To improve the transmission efficiency of the spread spectrum receiver by detecting an optional interference wave by a means which detects the frequency of a desired wave included in a received signal and further removing the interference wave by an interference wave removing means. CONSTITUTION:The received spread signal which contains the interference wave is inputted to an adder 2 and a multiplier 3 through a BPF 1. The signal from a voltage- controlled oscillator 5 whose frequency is controlled by a voltage sweeper 6 is inputted to the multiplier 3, which outputs a spread signal. This signal is passed through an LPF 4 to remove its high-frequency component and inputted to an integrator 8, which outputs a DC voltage. When this output voltage becomes higher than the voltage of a comparison part 9, the comparator 9 supplies its output signal to a control part 7, which sends a stop signal to the sweeper 6. Consequently, the output signal of the oscillator 5 is fixed and its frequency becomes equal to that of the interference wave. This signal is inverted in phase by a 180 deg. phase shifter 10 and inputted to the adder 2, which removes the interference wave component of the received spread signal. Consequently, the transmission efficiency of the receiver is improved. |
