| 摘要 |
When a television signal is not received, supply of a power supply voltage to the inner circuits is stopped to save the electric current consumed. A television tuner comprises at least a mixer circuit for frequency-converting a television signal to an intermediate-frequency signal, a local oscillation circuit for inputting a local oscillation signal to the mixer circuit, an intermediate-frequency amplifier circuit for amplifying the intermediate-frequency signal, and a PLL circuit for controlling the oscillating frequency of the local oscillation circuit, the television tuner further comprising switch means for supplying a power supply voltage to the mixer circuit, the local oscillation circuit, the intermediate-frequency amplifier circuit, and the PLL circuit, wherein when the television signal is received, the switch means is turned on, and when the television signal is not received, the switch means is turned off.
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