Spindle drive control system

摘要

Disclosed is a rotational speed control system for comparing the rotational speed of a rotating disk as indicated by index pulses occurring one or more times per revolution of the disk, with a reference time representing the desired time between successive index pulses. The system employs logic circuitry external to any microprocessor control system employed by the rotating disk system. The reference time may be supplied by counters counting externally supplied clock pulses to a fixed value. The speed control system provides a speed up command or slow down command in a manner proportional to the speed error to the disk drive motor where the time between successive index pulses is greater or less, respectively, than the reference time.