| 摘要 |
PURPOSE:To obtain high operation stability, and to simplify LSI-implementation by linearly converting the output of a companding type A/D converter for AGC operation on a data transmission system. CONSTITUTION:Analog input signals are supplied to companding type A/D converter 31, whose outputs are supplied to nonlinear-to-linear converter 32, so that its digital outputs will be made to correspond to analog input signals of converter 31 respectively. By being multiplied by the output signal from multiplier generating circuit 26 at multiplier 23, the linear digital signal is sent to the next stage as an automatically-gain-controlled digital output. In this case, some of the output of multiplier 23 is lead into level supervisory circuit 25, the output equivalent to the detected level variation is supplied to circuit 26, and the corresponding multiplier is given to multiplier 23 from circuit 26, thereby attaining the AGC operation. |
