摘要 |
A digital servo circuit which comprises a first N-bit counter for counting clock pulses at a recurrence frequency corresponding to error data and a second N-bit counter for counting divided recurrence frequency clock pulses at 1/M times the aforementioned recurrence frequency. The digital servo circuit controls the pull-in operation of a servo system with the count output of the second N-bit counter as control data, while it controls the operation of the servo system in the normal phase-locked state thereof with the count outputs of the first and second N-bit counters as control data with the count output of the second N-bit counter changed according to the amount of external disturbance caused to the servo system. |