| 摘要 |
In an automatic tuning system for a loop antenna having a single electronically variable reactance element, the reactive component sense of the antenna impedance is determined over a wide range of frequency. The electronically variable reactance component of the antenna is automatically minimized by a feedback loop driving a voltage variable capacitance until the reactive component of the antenna impedance is virtually zero and the antenna impedance is hence resistive. The adjustment of the electronically variable capacitance is by a variable high voltage power supply controlled by a feedback amplifier or by a high voltage feedback amplifier.
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