| 摘要 |
The condition monitor provides information as to the state of a monitored dual state device having, for example, possible satisfactory and unsatisfactory conditions. Use is made of a passive transducer element powered by a space-transmitted radio frequency signal of fundamental carrier frequency. In the unsatisfactory condition of the monitored device, the passive transducer emits a signal that is a harmonic of the carrier frequency, which signal is detected for the operation of a suitable alarm or remedial control. In the normal or satisfactory condition of the monitored device, the carrier frequency energy causes the passive transducer to inhibit production of second harmonic energy.
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