| 摘要 |
<p>A digital servo system for a rotating member which detects a difference between phases of a reference signal and a signal representing the rotation phase of the rotating member thereby to control its rotation in accordance with the phase difference. Comparison is made by a digital rotation phase comparator between points of time at which first and second predetermined counts are made by a clock pulse counter which is cleared for each period of the reference signal and a point of time at which the rotation phase information signal of the rotating member is produced. When the rotation phase signal appears during an interval between the first and second counts, a latch signal is generated in synchronization with the rotation phase signal to cause an instantaneous count between the first and second counts of the counter to be loaded into a latch circuit. A pulse width modulator generates a pulse train whose width corresponds to the latched count; and the rotation of the rotation member is controlled in accordance with a DC output voltage level of a driving circuit which corresponds to the pulse width of the pulse width modulated signal.</p> |
