| 摘要 |
PURPOSE:To provide an AGC circuit for audio apparatus which realizes quick AGC response without the silent state or the occurrence of cracking sounds at the time of the amplitude change of an input signal. CONSTITUTION:This AGC circuit consists of a first AGC circuit 1, which is provided with a first audio signal level control means 5 to which first AGC feedback loops 6 to 12 are connected and has a slow AGC control response characteristic, and a second AGC circuit 2 which is provided with a second audio signal level control means 13 to which second AGC feedback loops 14 to 20 are connected and has a quick AGC control response characteristic, and first and second AGC circuits 1 and 2 are cascaded to an audio signal line. When the input signal whose amplitude is quickly increased is supplied to an input terminal 3, the first AGC circuit 1 converts it to a signal whose amplitude is temporarily increased and is fixed after a long time, and the second AGC circuit 2 converts it to a signal whose amplitude is temporarily slightly increased and is fixed after a short time. |
