Input circuit of television tuner in which interference caused by FM broadcasting signal is attenuated

摘要

An object of the present invention is to switch a television signal or an FM broadcasting signal by a small number of active elements, to input the switched television signal or FM broadcasting signal to an input tuning circuit, to reduce loss in the television signal when the television signal is received, and to reduce interference due to the FM broadcasting signal when the television signal is received.;According to the present invention, an the first input terminal 1 is connected to the input end 6a of the input tuning circuit 6, first and second diodes 15 and 14 are serially connected between the second input terminal 11 and the input end 6a of the input tuning circuit 6 and are simultaneously switched on or off, the first diode 15 is input to the input end 6a of the input tuning circuit 6, the second diode 14 is provided at the side of the second input terminal 11, an inductance element 12 is interposed between the second input terminal 11 and the second diode 14, and a first capacitance element 17 that forms a low pass filter together with the inductance element 12 in a state when the second diode 14 is switched on, is connected between the connection point of the first diode 15 and the second diode 14 and a ground.