| 摘要 |
PURPOSE:To prevent changes in the amplitude of the output signal of an encoder, by regulating the current to be supplied to a light emitting element so that a value will coincide with a reference value as obtained after a received light signal is converted into a signal oscillating centered on 0V, full-wave rectified and integrated. CONSTITUTION:In an optical type encoder having a light emitting element 2 and a light receiving element 3, a signal obtained from a light receiving element 3 is converted into a signal oscillating centered on 0V through a capacitor 6 and an amplifier 7. Then, the signal is full-wave rectified with a normal amplifier 8, an inversion amplifier 9 and diodes 10 and 11 for clip and integrated with an integrator 14. Then, the integrated value is compared with a reference value generated with a Zener diode 16 to control the value of current to be supplied to the light receiving element 2 so that the comparison output will be zero. Thus, mechanical errors of the encoder are corrected to always obtain a constant output signal. |
