| 摘要 |
PURPOSE:To unnecessitate adjustment, compose a device of integrated circuits, stabilize the operation thereof and miniaturize the device by composing the device mainly of digital circuits on the occasion that the displacement of various process amounts is detected and transduced into electric signals. CONSTITUTION:The output of a variable-capacity type sensor SS is inputted to a switching part SW composed of FETQ1 and Q2. The output of the switching part is inputted to an exciting part EX and the oscillation of the 1st frequency is performed when FETQ1 is turned on, while the oscillation of the 2nd frequency is performed when FETQ2 is turned on. At a control part CT, the output of the exciting part EX and the output of an oscillator comprising an inverter IN2, etc. are given alternately to the clock input CL of a counter CT1 and finally control voltage is impressed on a diode D, whereby the oscillation frequency of the oscillator by the inverter IN2 is controlled. When the 2nd frequency and the oscillation frequency of the inverter IN2 are made equal to each other by such a constitution, a sampling period wherein the oscillation of the 2nd frequency is performed and a lock period wherein the oscillation of the 1st frequency is performed can be set in the same period. |
