Colour TV signals processing system - uses modified signal derived from chrominance frequency band of adjacent lines

摘要

The system is designed to separate the luminance component of a composite PAL colour television input signal. The systems has a circuit which provides a modified line signal with each line of an input signal. The modified line signal is derived from the chrominance frequency band of one of the adjacent lines of input or both of them. The signal is modified by reversing the phase of the component. A subtractor subtracts from the input signal and modified signal or from a signal derived from the latter, with the same instantaneous phase of the instantaneous colour sub carrier. The subtraction produces an output luminance signal.