Patent ID: 7190414
Filing Date: 2007-03-13
Classification: H03J

Abstract:
1. An input circuit of a television tuner, comprising: a first input terminal to which a television signal is input; a second input terminal to which an FM broadcasting signal is input; an input tuning circuit tuned to the television signal and the FM broadcasting signal, wherein the first input terminal is connected to an input end of the input tuning circuit; first and second diodes serially connected between the second input terminal and the input end of the input tuning circuit and simultaneously switched on or off, wherein the first diode is input to the input end of the input tuning circuit, and wherein the second diode is provided at a side of the second input terminal; an inductance element interposed between the second input terminal and the second diode; a first capacitance element that forms a low pass filter together with the inductance element when the second diode is switched on and is connected between a connection point of the first diode and the second diode and a ground; an FM trap circuit provided between the first input terminal and the input end of the input tuning circuit for attenuating an FM broadcasting band; and a fourth diode connected between the connection point of the first diode and the second diode and an input end of the FM trap circuit, wherein the fourth diode is switched on or off simultaneously with the first, second, and third diodes.