| 摘要 |
PURPOSE: A clock regenerating device is provided to stably follow up an inputted digital signal even when the digital signal is disturbed. CONSTITUTION: The clock regenerating device comprises: an oscillating element for generating a clock signal having a frequency according to an inputted first or second signal; a first generating element for comparing a frequency of an inputted reference signal with a frequency of the clock signal and generating a first comparing signal according to a frequency difference between the inputted reference signal and the clock signal; a second generating element for comparing a phase of the digital input data with a phase of the clock signal and generating a first comparing signal according to a phase difference between the digital input data and the clock signal; a first transfer element for selecting one of the first comparing signal supplied from the first generating element and the second comparing signal supplied from the second generating element, and for outputting the selected signal to the oscillating element; and a control element for examining if the frequency difference between the reference signal and the clock signal falls within a predetermined range, controlling the first transfer element so that the first comparing signal generated by the first generating element is selected when the frequency difference is out of the predetermined range, and for controlling the first transfer element so that the second comparing signal generated by the second generating element is selected when the frequency difference falls within the predetermined range.
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