| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce costs by using Walsh-Hadamard transformation(WHT) for plural sample values in the digital decoding of composite video signal CVBS at a decoder to simplify calculation and a circuit. SOLUTION: The CVBS is inputted to an input sample rate converter 32 and a video signal digitized at a prescribed clock frequency by a line and phase locked loop 33 is converted to the four-times sampling frequency value of color subcarrier frequency. After a vertical WHT circuit respectively adds and subtracts samples corresponding to two video image lines, a horizontal WHT circuit 35 alternately transforms the low-passed and high-passed sample values for each line to WHT areas while using WHT. A color difference component is separated from a provided WHT matrix by a control and setting circuit 36, transformed to original pixel areas while using respective horizontal and vertical inverse WHT 39 and 40 and outputted through sample rate conversion. Thus, setting and control can be executed as a whole by multiplying the WHT areas while using only one multiplying step.</p> |
