| 摘要 |
A simple, reliable, compact and inexpensive fluid pressure discontinuity analysis system includes a basic capacitive pressure transducer, made of two closely spaced insulating plates whose opposed faces contain conductive layers, and one of which plates is a flexible diaphragm of low mechanical hysteresis. The transducer is coupled to a variable pressure source which under normal operating conditions remains at a substantially constant pressure level. The output signal from the transducer has its high-frequency AC component attenuated by a low-pass filter, whose output in turn has its DC component substantially removed by capacitive blocking, after which the remaining AC output is then amplified by a circuit including an operational amplifier. This AC-amplified signal is then compared with a "reduced-magnitude average" reference signal (produced by an AC-to-DC conversion side-circuit followed by magnitude-level adjustment). The comparator output triggers a one-shot monostable multivibrator used to produce an on-off switching signal which operates an alarm signal.
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