| 摘要 |
PURPOSE:To stabilize temperature characteristics and to simplify IC-implementation by employing digital constitution for a TV receiver. CONSTITUTION:An IF signal obtained from tuner 2 is extracted 10 periodically within a certain time, extraction signals are counted 12, and logic circuits 13 and 14 discriminate judging from the counting output whether or not the IF frequency is within the fixed extent; when it is without the extent, a voltage equivalent to the exceeding direction is supplied to local oscillation part 5 of tuner 2, thereby controlling its frequency. Consequently, the IC-implementation can be simplified. |
