发明公开
EP1069681A2 Switchable buffer circuit 审中-公开
可切换的缓冲电路

Switchable buffer circuit
摘要:
Disclosed herein is a frequency-characteristic switchable buffer circuit (1) capable of increasing attenuation of a spurious frequency signal upon selection of a second frequency signal. The frequency-characteristic switchable buffer circuit includes an amplifying stage (2), a parallel resonance circuit (3) which serves as an output load of the amplifying stage, a frequency trap circuit (6) electrically connected between the input of the amplifying stage and a reference potential point, and a frequency switching voltage generator (20,21) for selectively generating a first switching voltage or a second switching voltage. The parallel resonance circuit parallel-resonates at a first frequency when the first switching voltage is supplied thereto. When the second switching voltage is supplied thereto, the parallel resonance circuit parallel-resonates at a second frequency. The frequency trap circuit comprises a series circuit made up of a diode (6 2 ) and a capacitor (6 1 ). When the first switching voltage is supplied to the frequency trap circuit, the frequency trap circuit series-resonates at a frequency lower than the first frequency. When the second switching voltage is supplied thereto, it series-resonates at any of frequencies lying within at 1700MHz band, which is higher than the second frequency.
公开/授权文献
信息查询
0/0