| 摘要 |
PURPOSE:To perform the compensation of the fluctuation characteristics of the width of a rectangular wave output signal based on the temperature fluctuation of light emitting and receiving elements and the reduction in the amount of light of the light emitting element, by obtaining the average value of two detected voltages, which have 180 deg. phase difference in electric angles of A+ and A-, and making the average value a reference voltage. CONSTITUTION:A fixed slit of A+ and a fixed slit of A-, which is 180 deg. out of phase in electrical angles, are added, and the detected signal, which have 180 deg. phase difference, are obtained at the A+ and A-. In this case, voltages, which are detected by light receiving elements 2a and 2a', are applied to a two resistors R6. An average value S' is obtained at a point, where the outputs of the resistors are combined. With the voltage S' as a reference voltage, adjustment is performed by variable resistors VR7. Voltages S2' and S3' are inputted to waveform shaping circuits 5b and 5c for detected voltages B+ and Z+. Adjustment is performed so as to obtain the specified rectangular wave outputs. |
