Abstract: A method and apparatus for providing very small changes in the output oscillation of a controlled oscillation circuit, which may be used in a phase locked loop circuit, is accomplished by a phase-shifting controlled oscillator that includes an oscillation circuit and a selection circuit. The oscillation circuit generates a plurality of oscillations that are of approximately the same frequency and are approximately equally phase shifted from one another. The selection circuit is operably coupled to receive the plurality of oscillations and selects one of them to be the output oscillation based on a control signal. The very small change in the output oscillation occurs when the selection circuit, based on the control signal, selects another one of the oscillations to be the output oscillation. When the change happens, a single pulse is stretched by the phase difference between the “old” output oscillation and the “new” output oscillation.

Abstract: A method and apparatus for detecting differences between an image update rate and a display update rate and to provide a viable solution that produces minimal adverse visual effects is achieved by first detecting an image delineation from a stream of images. The image delineation is then used to determine the image update rate which is compared to the display update rate to produce a relationship between the two update rates. The relationship is then compared to a plurality of desired relationships to determine if it is sufficiently similar to one or more of the desired relationships. If it is, an image display pattern associated with the desired relationship is used. For example, if the relationship is sufficiently similar to the desired relationship of 1:1, then the image display pattern will be 1111 . . . In other words, the image display pattern would display each received image once.

Abstract: A method and apparatus for controlling an output frequency of a phase locked loop is accomplished by determining a plurality of divider ratios which are based on an input frequency, parameters, and a desired output frequency. Each of the divider ratios is representative of a ratio between the output frequency and input frequency of the phase locked loop. Having determined the plurality of divider ratios, another determination is subsequently made to determine whether the plurality of divider ratios enable the phase locked loop to produce the output frequency within a given frequency tolerance, i.e., within an allowable error. The determination is based on whether changing the divider ratio from the one of the plurality of ratios to an adjacent ratio causes the output frequency to change more than the allowable error. If so, the plurality of ratios needs to be recalculated based on a change in the input frequency and/or one of the parameters.