Colour purity circuit for TV sets - prevents wrong colours under high illumination and removes red and blue difference signals to eliminate green tinge

摘要

The colour purity circuit, for colour television cameras, prevents wrong colours arising under high illumination - ie prevents the strong green difference signal due to the red and green colour components having no effect. When the luminance signal (W) exceeds a given level, the red and blue colour difference signals are blanked out. The luminance signal is applied to a threshold trigger (1) that controls two blanking switches (2, 3), one in the R W channel and the other in the B W channel. When a given luminance signal.