video combiner

• PAL (Phase Alternation Line) is a colour TV system developed in Germany and generally adopted in Europe. In France, however, the SECAM (SEquential Couleur A Memoire) system is used. The colour burst signal is a phase and amplitude reference signal which is used to demodulate the chrominance signal. The luminance signal con- tains brightness information; it is obtained by combining the outputs of the three colour channels and then used for amplitude modula- tion of the main picture car- rier frequency. The chrominance signal is obtained by combining, in the logic decoder and chroma encoder, portions of the separate colour logic levels into sum and dif- ference signals. Two quadrature components of the chrominance signal are produced and used for amplitude modulation of the chrominance subcarriers. Figure 1. This block schematic of the TEA 1002 clearly shows the complexity of the cir- cuitry required to pro- duce a composite colour video signal. The video combiner is a circuit w...