servo system for a rotan you comprising a detector of the difference of phase between a signal and a reference signal to measure

摘要

A control circuit for a rotating object, such as is found in a tape recorder, has two control loops. The first takes the output signal of a phase detector, which is dependent upon a phase difference, between a reference source and the rotating object, and applies it to a speed control means. The second loop converts the phase detector output signal into a signal that is dependent upon a frequency difference and the duration of the frequency difference and applies it to the speed control means.