| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit which corrects a reference frequency error and errors for every facet by using a phase-locked loop. SOLUTION: The phase-locked loop includes a digital phase detector whish measures the time differences between the ends of scanning of each facet and the ends of counting and stores them in a look-up table. The phase-locked loop generates a mean time value continuously from the time differences of all the faucets of a polygon. Further, the phase-locked loop adds errors of each facet to the mean time value and uses the result to correct the frequency of a pixel clock generator for both the reference frequency error and the errors for every facets. |
