| 摘要 |
PURPOSE:To easily and accurately set the range of an output voltage and follow-up speed with simple constitution, by performing automatic gain control synchronizing with a synchronizing signal based on the output signal of a voltage comparator which compares the output voltage with a reference voltage. CONSTITUTION:The titled circuit is equipped with an amplifier circuit 10 which amplifies an analog signal, the voltage comparators 12a and 12b which compare the output voltage of the amplifier 10 with a prescribed level of reference voltage, and storage circuits 13a and 13b which store the output signals of the voltage comparators 12a and 12b as logical values. And also it is equipped with selection circuits 14 and 15 which output a selection signal that selects the prescribed gain resistance of the amplifier circuit 10 synchronizing with the synchronizing signal based on the output signals of the storage circuits 13a and 13b, and a switching circuit 16 which switches the prescribed gain resistance of the comparator 10 based on the output signals of the selection circuits 14 and 15. The magnitude relation of the output voltage and the reference voltage is stored in the storage circuits 13a and 13b as the logical values, and the gain resistance of the amplifier is switched synchronizing with the synchronizing signal based on the above storage information. In such a way, it is possible to change an amplification factor and to keep the amplitude of the output voltage in spite of the value of the amplitude of an input signal.
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