| 摘要 |
PURPOSE:To obtain a sinusoidal wave output or a pseudo-sinusoidal wave output having a constant amplitude, by arranging two sets of light emitting elements and light receiving elements on both sides of a rotary disk in-between. CONSTITUTION:On both sides of a rotary disk 1, two sets of light emitting elements 3 and 6, fixed disks 4 and 7 and light receiving elements 5 and 8 are provided, so that they are symmetrical with respect to a rotary shaft 2 as a center and the phases of the AC components of the outputs of the elements 5 and 8 become equal. The outputs of the light receiving elements 5 and 8 become waveforms A1 and A2 and include a ripple frequency, whose one period is one rotation of the disk 1. The waveforms A1 and A2 are amplified, and A'1 and A'2 are obtained. The wavelforms A'1 and A'2 have the same phase and have the phase difference of 180 deg. with respect to the ripple frequency having an amplitude, whose one period is one rotation (a) of the disk 1. When the waveforms A'1 and A'2 are added and amplified, the ripple frequency having the amplitude, whose one period is one rotation of the disk 1, is cancelled. Then, a sinusoidal wave output or a pseudo-sinusoidal wave output having a constant amplitude such as a waveform As can be obtained. |
