12 - Introduction to composite NTSC and PAL

Abstract

This chapter elaborates on composite National Television System Committee (NTSC) and Phase Alternate Line (PAL) encoding. Composite NTSC and PAL color coding use quadrature modulation to combine two color difference components into a modulated chroma signal. Composite encoding was invented to address three main needs. First, there was a need to limit transmission bandwidth. Second, it was necessary to enable black-and-white receivers already deployed by 1953 to receive color broadcasts with minimal degradation. Third, it was necessary for newly introduced color receivers to receive standard black-and-white broadcasts. Composite encoding was necessary in the early days of television, and it has proven highly effective for broadcast. NTSC and PAL are used in billions of consumer electronic devices. The chapter also highlights three major disadvantages related to composite NTSC or PAL. In principle, NTSC or PAL color coding could be used with any scanning standard. However, in practice, NTSC and PAL are used only with 480i and 576i scanning, and the parameters of NTSC and PAL encoding are optimized for those scanning systems.