| 摘要 |
PURPOSE:To attain miniaturization of the titled device and to enhance accuracy, by obtaining a static pressure signal using the modulation cycle obtained at the output terminal of a counter and correcting static pressure using a difference pressure signal obtained in an integrating condenser. CONSTITUTION:Either one of a first and a second amplifying means Q1, Q2 is selected by a selector 22 and variable voltage is amplified on the basis of the capacity ratio of sensor capacity and fixed capacity. The amplified voltage is returned to reference voltage by the discharge current from a discharger 24 but the time required in this returning determines the half-cycle of oscillation. After oscillation was repeated the predetermined number of times, either one of said amplifying means Q1, Q2 is changed over to the other through a counter means. Variable voltage is controlled so that the average voltage of the outputs of the counter means CT comes to zero by both oscillations. Because this variable a voltage is proportional to difference pressure and the cycle of the output pulse of the counter means CT is proportional to the dielectric constant of a seal liquid, predetermined operation is applied to the variable voltage using the cycle and temp. signal of the counter means to obtain a difference pressure signal compensated in static pressure.
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