| 摘要 |
PURPOSE: To prevent oscillation by detecting a bypass signal amount from a transmission antenna to a reception antenna. CONSTITUTION: A pilot signal FP with a frequency different from a received frequency is injected to an amplifier 2 from a pilot signal oscillation circuit 8, and a pilot signal detection circuit 11 at an input side of the amplifier 2 detects the level of a bypass signal FP' of the pilot signal. Then a phase of the detected bypass signal FP' of the pilot signal is compared with a phase of the pilot signal FP and a phase shift amount of a phase shifter 3 is controlled with a phase control signal 9 so that the phase of the bypass signal FP' is inverted to minimize a danger of oscillation. Thus, even when a signal level of a bypass signal 5 of a transmission signal 10 is increased by any causes, since the phase of the bypass signal 5 is inverted to the phase of the reception signal 6, the oscillation of the relay amplifier is not caused. |
