| 摘要 |
An acoustic thermometer of the resonant sensor type relies for its operation on variations in the resonant frequency of an acoustic resonator with temperature. Pulses of ultrasound are supplied over an acoustic resonator with temperature. Pulses of ultrasound are supplied over an acoustic transmission line to the acoustic resonator and an automatically operating electronic arrangement varies the frequency of the ultrasound to maintain the acoustic resonator in resonance as the temperature varies. The echo signals returned down the transmission line each include a crossover in their waveform, and the electronic arrangement operates by maintaining the echo signal before crossover precisely in antiphase with the echo signal after crossover.
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