| 摘要 |
PURPOSE:To decrease the return time at steady-state, by limiting the amplitude from the limiter when an input signal is rapidly increased from the limiter and a surge is input to the input. CONSTITUTION:The input signal from the line (a) is amplified by the gain determined with the level of the line (d) with a variable gain control amplifier 1 and becomes the output signal of (b). When the output signal level of (b) is increased than the level of the line (c), a current flows to a resistor 2 and a diode 3, a capacitor 4 is charged with the time constant determined with the resistor 2, and the level of the line (c) is increased, the output (d) of an amplifier 7 is increased and the gain of the amplifier 1 is decreased. In this case, a limiter 8 is provided which makes limit with a slightly higher level than the reference voltage, allowing the limiter 8 to limit the amplitude, if the input signal is rapidly increased and a surge is input to the input. Thus, the capacitor 4 is charged to a slightly higher value than the reference voltage, allowing to reduce the time returned at the steady-state. |
