AMPLITUDE LIMIT METHOD FOR DIGITAL COLOR VIDEO SIGNAL AND AMPLITUDE LIMIT DEVICE

摘要

PURPOSE: To limit the amplitude of a color video signal with a small circuit scale by replacing a main digital luminance signal and a sub digital luminance signal resulting from amplitude-limiting 1st and 2nd main digital color difference signals respectively with 1st and 2nd sub digital color difference signals. ;CONSTITUTION: A digital D₂ composite color video signal from an input terminal T₁ is separated into a digital luminance signal Y and a digital chrominance signal C at a Y/C separation circuit 1. The signal C is inputted to a decoder 2 to obtain digital color difference signals U:2, V:2 whose frequency ratio is 2:2. The signal Y, the signals U, V are inputted to a delay circuit 23 and a changeover circuit 24. On the other hand, the signal Y and the signals U:2, V:2 are converted into signals Y, U', V' whose sampling frequency ratio is 4:14:4 via a circuit 13, given to a matrix circuit 14, in which three primary color signals R:4, G:4, B:4 are obtained and the amplitude is limited by a limiter 15, the signal is processed by a matrix circuit 17 to obtain amplitude limit luminance signals Y₁, UL', VL', the circuit 18 halves the frequency to use the circuit 24 to replace the signal from the delay circuit 23 and it is outputted via the circuit 9.;COPYRIGHT: (C)1994,JPO&Japio