| 摘要 |
PROBLEM TO BE SOLVED: To reduce the interference due to the leak by outputting a pilot signal under a prescribed condition and controlling the amplitude and phase of a feedback signal based on the signal inputted then in regard to a means which feeds an output signal back to the input side and eliminates the leak signal component. SOLUTION: The signals inputted to a directional saucer-shaped antenna 13 from a base station are amplified and sent to a wireless terminal via an omnidirectional antenna 14. However, some of these amplified signals are inputted to the antenna 13 via a leak path 28 and causes the interference. A phase amplitude control circuit 31 shifts the phase of the sampling output signal sent from a directional coupler 30 by 180 degrees and feeds back the output signal via a directional coupler 33 to eliminate the leak signal component. A voltage control oscillator 40 transmits a burst-shaped pilot signal of 100n seconds via the antenna 14 when a normal signal is kept at a low level. A null circuit 39 analyzes the signals inputted via the antenna 13 and sets the circuit 31. |
