Composite-Component Transformation and Predictive Coding of the Component Color TV Signal

Component coding of the NTSC color TV signal is investigated. This coding involves digital demodulation of the composite signal sampled at three times the color subcarrier frequency, the implementation of the compression algorithms on the subsampled component signal, and digital reconstruction of the processed NTSC color signal. The comb filter, bandpass filter, and Hilbert transformer are used for the demodulation of the luminance and the and chrominance signals. The reconstructed components at the receiver are interpolated and modulated to obtain the composite signal. Different combinations of comb filters, bandpass filters and Hilbert transformers are used to investigate their effect on compositecomponent separation and reconstruction. Because of their reduced bandwidths, the chrominance signals are subsampled both horizontally and vertically. Several intrafield and intraline predictors are simulated. Of these, three predictors with small variances of the prediction error are combined with 4 and 3 bit Max quantizers for further processing and transmission in a TDM format. The data compression algorithms have been applied to color test pictures and their effectiveness is compared on the basis of quantitative criteria. The bandwidth reduction technique results in digital transmission of a single color TV signal at 32-43 Mbits/s.