NTSCfärgkodning

NTSCfärgkodning refers to a specific method of encoding color information for analog television systems, primarily used in North America and some other parts of the world by the National Television System Committee (NTSC). This system transmits a composite video signal, which combines luminance (brightness) and chrominance (color) information into a single channel. The chrominance signal is modulated onto a subcarrier frequency, typically around 3.58 MHz.

The NTSC encoding process involves separating the color information into two components, typically designated as I (in-phase) and Q (quadrature) signals, or U and V in later standards. These components represent color hue and saturation. The NTSC standard uses a specific phase and amplitude relationship for these color components on the subcarrier to represent different colors. A key feature of NTSC is the use of a color burst signal, a short sequence of the subcarrier wave transmitted after each horizontal scan line. This burst signal allows the television receiver to synchronize its demodulation of the chrominance signal, ensuring accurate color reproduction.

However, the NTSC system is known for its susceptibility to color phase errors, which can lead to shifts in hue. This is partly due to the way the color information is interleaved with the luminance signal. Variations in transmission path or receiver circuitry can cause these errors. While NTSC was a significant advancement for color television, it has largely been replaced by digital television standards like ATSC in many regions due to its limitations in color accuracy and resolution.