OSCILLATOR FREE-RUNNING FREQUENCY ALIGNMENT METHOD USING DATA BUS CONTROL

摘要

PROBLEM TO BE SOLVED: To provide an alignment method of a free-running frequency of a synchronizing signal pulse generator in which the same setup and alignment performance is held and simplified.

SOLUTION: In the free-running frequency alignment method of a first oscillator of a video display including the synchronizing signal generator, the synchronizing signal generator is composed of the first oscillator having a first frequency and a second oscillator having a second frequency. The first oscillator is phase-modulated by the second oscillator having a free-running frequency different from a reference frequency. The free-running frequency of the first oscillator should be aligned controllably to the reference frequency by the method of applying a frequency determination initial control value to the first oscillator and measuring an average free-running frequency in accordance with the initial control value. A difference frequency between the absolute values of the average frequency and the reference frequency is calculated, and a new control value is generated in accordance with the difference. The new control value is applied to the first oscillator for adjustment into the reference frequency.

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