| 摘要 |
PURPOSE:To prevent the occurrence of waveform distortion and aging by constituting a feedback group with a subtractor, mean value circuit and integrator and providing a level decision circuit which controls the feedback group from the outside. CONSTITUTION:The signal entering from an input signal 100 is fed to a subtractor 2 and level decision circuit 1. The subtractor 2, mean value circuit 3 and integrator 4 constitute a feedback group and when the output of the integrator 4 becomes equal to DC offset voltage, it converges. The mean value circuit 3 averages the output of the subtractor 2 and feeds only the code of the mean value to the integrator 4. In the integrator 4, micro-voltage is integrated by the code of the mean value and the integrated value thereof is fed as DC offset voltage to the subtractor. On the other hand, if the input level is large to a certain extent, there is possibility that the mean value has been disturbed by the input signal and therefore the level decision circuit 1 so controls the integrator 4 as to stop its operation. The output of the subtractor 2 is fetched from output terminal 200. |
