| 摘要 |
PURPOSE:To improve the AGC characteristic at a low level region of an input signal with the same loop gain as that of a conventional AGC circuit by adding an offset level to an AGC pilot signal level at the input point of the AGC circuit. CONSTITUTION:In adding the offset level DELTAep to the pilot signal of a level ep included in the input signal in a form of subtraction in an offset addition circuit 4, the level of the pilot signal inputted to a gain control circuit 1 is ep-DELTAep, the effect of the level DELTAep is neglected in the range of a large input signal and the AGC characteristic as that of a conventional system is obtained. When the input signal level is lowered and the level ep approaches the level DELTAep, the AGC circuit 1 discriminates that a level lower than the actual input level by the DELTAep is inputted and the circuit 1 is controlled so as to increase the gain by the share. |
