| 摘要 |
A variable inductor usable in a fast tuning RF network comprises a plurality of inductor switching circuits connected in series. Each inductor switching circuit includes an input terminal connected to a discrete inductor and to a PIN diode, and includes an output terminal connected to switches which are in turn connected to the parallel connected discrete inductor and PIN diode. The PIN diode operates in either the forward bias mode for switching out the respective discrete inductor, or in the reverse bias mode for switching in the respective discrete inductor. The PIN diode is forward or reverse biased by MOSFET switches one of which has a parasitic capacitor used to provide a charged rectified reverse bias voltage to the PIN diode to insure reverse bias operation during large voltage changes in the conducted RF signals. The MOSFET switches are controlled by logic signals so that rapid switching by computer or other processor control is possible. Electrical isolation of the logic control circuitry is provided by optically coupling the control signals to the MOSFET switches.
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