Abstract: A motor control device comprises a motor speed detector, a reference signal generator and a control circuit for controlling rotation of a motor in accordance with a reference signal from the reference signal generator and a speed signal from the motor speed detector. The control circuit includes means for eliminating a phase error component during a phase synchronization pull-in period.

Abstract: A motor revolution control apparatus has a motor, a pulse generator, a control device and a microprocessor (CPU, ROM, RAM, etc). A slit disc is mounted on the shaft of the motor. The pulse generator generates pulses corresponding to the number of slits formed in the slit disc. The microprocessor controls each time interval (between the pulse corresponding to a given slit upon a first revolution of the slit disc and the pulse corresponding to the given slit upon a second revolution thereof) to be constant, thereby performing high-precision revolution control regardless of a slit interval error.