| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent disturbing waves which have partly passed a trap circuit or have been dropped to ground by a trap circuit and then reentered via a diode from entering a semiconductor element in a later stage. <P>SOLUTION: An input circuit 20 of the television tuner is connected at one end to an antenna input terminal 1 and connected at the other end to an electronic circuit having a wideband amplifier circuit 6. The input circuit 20 is interposed in series to a signal path between the antenna input terminal 1 and the electronic circuit, its resonance frequency being set to a first frequency, and includes a CB trap circuit 11 composed of a capacitor 111 and an inductor 112 which are connected in parallel. The CB trap circuit 11 has one end of an electrostatic protection diode 41 connected to one end thereof on the antenna input terminal 1 side and has one end of an electrostatic protection diode 42 whose polarity is an inverse of the electrostatic protection diode 41 connected to the other end thereof on the electronic circuit side, the other ends of the electrostatic protection diodes 41 and 42 being connected to ground. <P>COPYRIGHT: (C)2012,JPO&INPIT |
