| 摘要 |
PROBLEM TO BE SOLVED: To provide an electronic tuner equipped with a solution means so that signals more than a local oscillation signal can not leak into a phase locked loop(PLL) circuit. SOLUTION: While utilizing the LOCK output of the PLL circuit outputting the voltage of high level during a period before a PLL circuit 6 is stabilized and outputting the voltage of low level after stabilized, a transistor Q1 is operated for lowering an input reception signal to a mixer(MIX) circuit 4 concerning a period until the electronic tuner is normally turned into reception state. When the LOCK output is at the high level in a state before the PLL circuit 6 is stabilized, since the base voltage of the transistor Q1 is increased, a current flows to the collector and an impedance on a signal line is lowered. Therefore, the input signal to the MIX circuit 4 can be lowered and signals more than the oscillation signal from a local oscillator 5 do not leak into the PLL circuit 6.
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