| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable attenuation device with a simple circuit configuration where attenuation of a widely variable range is obtained in a small step. SOLUTION: This variable attenuation device consists of a serial circuit of plural selectable fixed attenuators 6 and a variable attenuation circuit 1. The circuit 1 preferably includes a varactor diode D, selects many pieces of digital data S6 stored preliminarily in a storage circuit 4 and is controlled with a small step, for instance 0.1 dB as a control voltage S4 of a prescribed range by a control circuit 2 through a D/A converter 3.
|
