Chrominance-luminance separator

摘要

An arrangement for the elimination of spurious chrominance component in the main luminance output signal from a chrominance-luminance separator of the comb filter type. The full band luminance signal from the comb filter is applied as one input to a switching circuit and the luminance component is also filtered by a low pass filter having a characteristic to roll off at the chrominance subcarrier frequency and applied as a second input to the switching circuit. The switching circuit is arranged to normally transmit the full band luminance component and to be switched to couple the filtered luminance signal only upon occurrence of spurious chrominance components in the luminance signal. The switching circuit is actuated by a control signal derived by comparing the top and bottom line signals in the comb filter and producing a gating signal for the switching circuit when there is a difference in the chrominance in the top and bottom lines.