Method and apparatus for calculating a divider in a digital phase lock loop

摘要

The method involves comparing (12) a reference oscillation (26) with a feedback oscillation (28), at a triggering event, to produce an error signal (30,32). The error signal is compared with a coarse threshold (36) and, if it compares unfavourably, a coarse divisor adjustment (40,18) is provided to a feedback divider (20). If the error signal compares favourably with the coarse threshold, it is compared with a fine threshold (38). If it compares unfavourably with the fine threshold, a fine divisor adjustment (42,18) is provided to the feedback divider.