| 摘要 |
<p>A television receiver is provided with an input terminal (12), and an input signal of a predetermined electric field strength inputted from the input terminal is converted to a video intermediate-frequency signal and an audio intermediate-frequency signal by a tuner (14). The video intermediate-frequency signal is amplified by a video intermediate-frequency amplifying circuit (16), and on the basis of the frequency, a detection signal (Va) is outputted from a filter (26). A reference voltage (Vref) is outputted from an RF-AGC circuit (32), and an RF-AGC circuit (30) generates a control voltage (Vb) in accordance with the difference between the detection signal and the reference voltage. The gain of the tuner is controlled by this control voltage. The reference voltage is changed by a microcomputer (36) in response to the control voltage. Therefore, the control voltage is adjusted to a desired voltage value.</p> |
