| 摘要 |
PURPOSE:To always enable the holding of the base line stably at the correct position by controlling the amplification output so that the difference becomes zero between the sum of time ranges of noise voltages distributing on the positive side and the sum of time ranges of noise voltages distributing on the negative side with respect to the zero voltage. CONSTITUTION:A noise voltage N at the output of an operational amplifier OPA is compared with the zero voltage by a comparator COM and when the voltage N is larger than it, the ouput of the COM gives a positive voltage while when the voltage is smaller than it, the output does the negative voltage. The output voltage of the COM is controlled so as to be equal in the positive and negative voltage with a limiter LIM and fed to the OPA through an LPF. Thus, the base line can be automatically held stably at the correct position. |
