| 摘要 |
A graphic system may include a pixel synthesizing device that uses two or more phase-locked loops (PLL's) in tandem in order to achieve a better M/N ratio. The two PLL's connected in tandem have an effective M/N ratio of (M 1 *M 2 )/(N 1 *N 2 ). The pixel synthesizing device is operable to synthesize free-running (non-genlocked, or sync-master) pixel clock frequencies using a much greater variety of M and N. As a result, greater precision in specification of the pixel clock frequency is achieved, yielding greater precision in a frame rate of a particular video format. As a result, the allowable channel spacing is greatly increased, and the graphic system can select from a wide range of ultradense spaced pixel clocks.
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