| 摘要 |
<p>PROBLEM TO BE SOLVED: To surely remove interference to a receiving signal due to the sneaking of a transmitting signal by providing a band stop filter by which a stop band is variably controlled and controlling the stop band in order to remove a reception frequency component in an operation from the transmitting signal. SOLUTION: The band stop filter 7 with a configuration where the stop band is variably controlled by a filter controller 8 is added at the output side of a band pass filter 2. A variable capacitance is arranged in a tuning circuit as the band stop filter 7, an applied voltage to the variable capacitance is variably controlled by a filter controller 8 to change the capacitance and the stop band is variably controlled. Thus, the reception frequency component is removed from the spectrum of the transmitting signal by the band stop filter 7 and, then, fed to transmission/reception sharing equipment 3. Therefore, the level of interference to the receiving signal which occurs by the sneaking of the component to a receiving part by the leakage of the transmission/reception sharing equipment 3 and the mismatching of an antenna is reduced.</p> |
