| 摘要 |
A measurement head particularly for borehole use can measure multiple parameters with no electronics in the head and only a single conductor cable. Double-ended tuning forks ( 26, 28 and 38, 40 ) in the head are arranged to respond to different parameters such as temperature and pressure by adjusting their resonant frequencies. A drive signal on the conductor ( 50 ) is applied to transducers ( 30, 32, 42, 44 ) on all the tuning forks and those whose instantaneous resonant frequency is close will resonate. The signal is removed and the transducers return a decaying signal at the resonant frequency along the conductor. Other drive frequencies are tried, to locate the other sensors whose frequency ranges are separate.
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