| 摘要 |
PURPOSE:To continue to adjust automatically a tracking constantly during the operation of a tuner by detecting a carrier level for adjusting the tracking and controlling a gain of an RF amplifier or an IF amplifier or the like at the same time. CONSTITUTION:The video carrier level detected in a tracking detecting part 18 is supplied to a microcomputer 26 through the output of a comparator 25 and the sound carrier level detected in the tracking detecting part 18 is supplied to the microcomputer 26 through an A/D converter 30 and a bus interface 31, respectively. Based on the supplied data, data for changing a voltage impressed to a preselector 1 and a flash cap diode of a band filter 3 is supplied to D/A converters 33, 34, 35 through a bus interface 32 and similarly, data for controlling the respective gains of the RF amplifier 2, the IF amplifier 19 and a DC amplifier 24 is supplied to a D/A converter 36 through the bus interface 32.
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