differentially device to adjust the phase of the analog signals in a system for processing of video signals

摘要

Digital TV receivers which digitally process chroma and luma signals in different channels and convert the digital signals to analog form before matrixing will include low pass analog filters after the DAC's to remove clock switching components. The luma and chroma analog filters will impose differing group delay on their respective signals. This creates a differential phase error between the analog signals which is corrected by predictively delaying the signal which leads in phase in the DAC. This is accomplished by using clocked digital-to-analog converters forced to operate synchronously with the data stream and appropriately delaying the clock signal applied to one of the DAC's relative to the other.