| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable attenuation circuit suitable for high frequency signals, which can be fabricated into IC and can set a big signal attenuation ratio by turning on/off of a switch using transistors. SOLUTION: The circuit comprises a first resistance connected between an input terminal and an output terminal, a second resistance with one end connected to the output terminal and the other and grounded to the earth, a base-biased transistor equipped with a collector connected to a power supply terminal and an emitter connected to the output terminal via capacitance and is connected to the input terminal, and a power supply with one end connected to the emitter via the switch and the other end grounded to the earth.
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