| 摘要 |
PURPOSE:To accurately detect the speed of a motor by measuring the speed of the motor up to the same resolving power as a quadruplex method and compensating the deterioration of the phase accuracy thereof. CONSTITUTION:The signals (phiA, phiB) shifted by 90 deg.C in phase obtained from an encoder and the reversal signals thereof are formed and signal cycles are measured by timer counters 142a-142d. At the predetermined taking-in sampling point of time, the measured values of cycles completed in measurement immediately before said point of time are discriminated by flip-flops 146-146d and the speed of a motor such as the rotational speed thereof is detected based on said values. The speed of the motor can be detected in the same resolving power as a quadruplex method and, since divided cycles are not measured but the whole of one cycle is measured, the effect of a factor deteriorating phase accuracy such as offset shift is eliminated and, since the speed of the motor is detected based on the measured data immediately before detection timing, the degree of detection delay is reduced. |
