| 摘要 |
PURPOSE: To provide a television tuner that can reduce number of resistors used for a DC circuit to turn on or off a switch diode, produce no distortion, even when a television signal with a high level is received by applying a reverse voltage between an anode and a cathode of the switch diode, when the switch diode is turned off and decrease the current consumption. CONSTITUTION: An input tuning circuit 3 (inter-stage tuning circuit 9) consists of a band switching tuning circuit, having tuning inductive elements 3a-3d (9a, 9b, 9d, 9e) and a switch diode 3f (9h, 9i) that switches the inductance, a power supply voltage is applied to each anode of the switch diodes 3f, 9h, 9i via independent anode side feeding resistors 5, 10, each anode is connected to ground via current conduction means 4, 8 in terms of DC, and a switching voltage at a high or low level is applied to each cathode via cathode side feeding resistors 6, 12 to switch a tuning frequency band of each tuning circuit.
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