US Patent 7460113 Digital pixel clock generation circuit and method employing independent clock

A digital pixel clock generation circuit receives image data and corresponding image presentation time information from at least one external image source. The digital pixel clock generation circuit includes an image presentation timing error determination circuit that produces desired pixel clock frequency control information, such as pixel output clock adjustment control information, based on a difference between an expected presentation time and an actual presentation image time information. A programmable digital waveform generation circuit is programmed based on the produced desired pixel clock frequency and has an input that is responsive to an independent clock source, that is independent from the clock source of the external image source. The programmable digital waveform generation circuit provides a digital representation of an independently generated desired pixel clock which is then output to a digital to analog converter (DAC).