| 摘要 |
A sensor for detecting a rotation speed outputs a detecting signal d expressing a speed superposed with an actual rotation speed d d and a variation amount d n based on whirling. By an adaptive filter 28 constituting a reference signal x by a signal generated by itself from a signal of the sensor, a cancel signal y for canceling the variation amount d n is calculated and the cancel signal is subtracted from the detecting signal d. As a result, a signal e expressing substantially the rotation speed d d is provided and therefore, based on the signal e, the rotation speed of the rotating member is calculated. |
