| 摘要 |
PURPOSE:To properly select a signal level performing an AGC operation when an input signal having plural levels is received. CONSTITUTION:An input signal having plural levels is amplified to an amplification signal by an amplifier. This amplification signal is compared with a target level in a level comparison part and the time ratio of the time when the target level is exceeded and the time when it is below the target level is determined. In a time ratio comparison part, the setting time ratio and the calculating time ratio are compared and a level selection signal is outputted. In a gain control part, a level to which a gain control is aimed is selected from the level selection signal and the selected level is adjusted to the target level. |
