| 摘要 |
A variable attenuation circuit includes an attenuation circuit which has a first semiconductor variable impedance element, and an attenuation control circuit of which the impedance is changed by a control voltage to be applied from the outside and which has a second semiconductor variable impedance element for controlling the impedance of the first semiconductor variable impedance element. The attenuation circuit and the attenuation control circuit are connected in cascade. Therefore, signals can be attenuated by the attenuation control circuit, in addition to the attenuation circuit.
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