| 摘要 |
<p>PURPOSE:To remove a servo error by storing the size of a phase error, determining a correcting variable and the direction of a residual error and automatically adjusting a phase locking position. CONSTITUTION:In an automatic residual error correcting circuit for a servo circuit, a correcting variable is determined on the basis of the contents of a phase detecting counter 120 at the input of a reference signal S (at the end of a phase detecting time) and stored in a moving variable counter 145. The direction of a residual error is transferred to a moving direction flip-flop (FF) 146, and at a time T1, the moving variable is added/subtracted by a correcting counter 147. At a time T2, the counted result (phase information) of the counter 120 is added/subtracted to/from the contents (residual error information) of the counter 147 to obtain feedback information MFD to be fed back to a speed loop. Even if the locking position is shifted due to the change of a load or the like, the shift can be turned to zero without fail and operation expanding DC gain to an infinite level can be expected at the time of sudden phase shift.</p> |
