| 摘要 |
PURPOSE:To raise DC output voltage and to obtain a stable high sensitivity characteristic, by constituting a synchronous rectifying circuit of an analogue switch reduced in resistance in a forward direction. CONSTITUTION:Four rectifying elements of a synchronous rectifying circuit 9a are constituted of analogue switches 10-13 turned ON and OFF by predetermined voltage and the output terminals 3, 7 of a high frequency oscillation circuit 1a are respectively connected to the respective gates of opposed switches 10, 12 and 11, 13. One of the terminals 3, 7 of the circuit 1a (or the other thereof) is connected to the middle 2 of the contacts (or both terminals 8a, 8b) of differential coils L1, L2 through an amplifier 14 (or 15) and an attenuation circuit 16. The rectangular oscillation voltage of the circuit 1a is inputted to the gates of the switches 10-13 and the switches 10-13 are opened and closed in synchronous relation to the input of said voltage. By this constitution, DC currents I1, I2 flow to the coils L1, L2 corresponding to the displacement of an object 4 to be measured in the direction 5 shown by an arrow and the DC voltage corresponding to the difference between both currents is generated at terminals E1, E2. Since the output of the oscillation voltage from the circuit 1a is stabilized by the circuit 16, DC output voltage is stabilized.
|
