| 摘要 |
A television tuner contains a mixer 4 for converting a television signal into an intermediate frequency signal and outputting it, an intermediate frequency tuning circuit 5 for tuning the intermediate frequency signal, an intermediate frequency amplifier 7 provided in an integrated circuit 10 and connected to the intermediate frequency tuning circuit 5 , and option circuits 2 and 3 provided at the side of the front stage of the mixer 4 for being switched into the operational state or non-operational state at a specific receiving band or channel. The integrated circuit 10 is provided with input terminals 10 a and 10 b for inputting the intermediate frequency signal output from the intermediate frequency tuning circuit 5 to the intermediate frequency amplifier 7 and a switch control circuit 9 for switching the operation of the option circuits 2 and 3 , where the switch voltage output from the switch control circuit 9 is supplied to the option circuits 2 and 3 through the input terminals 10 a and 10 b.
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