| 摘要 |
PURPOSE:To facilitate automatic compensation of an attenuator, by controlling a microprocessor. CONSTITUTION:Automatic compensation of an input attenuator 5 is accomplished by selecting the attenuation value fed from a programmable attenuator 17. So to speak, with a microprocessor 15, the voltage at the lower end of a trimmer condenser 20 is controlled to be the same supply voltage as that at the end connected to the output 6 of the attenuator 5. The effective value of the condenser 20 is changed by varying the attenuation ratio of the attenuator 17, thereby enabling automatic compensation of the attenuator 5.
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