Analog television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by amplitude, phase and frequency of an analog signal.
Phase Alternating Line (PAL) is a colour encoding system for analog television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields per second, and associated with CCIR analogue broadcast television systems B, D, G, H, I or K. The articles on analog broadcast television systems further describe frame rates, image resolution, and audio modulation.
SECAM, also written SÉCAM, is an analog color television system that was used in France, Russia and some other countries or territories of Europe and Africa. It was one of three major analog color television standards, the others being PAL and NTSC. Like PAL, a SECAM picture is also made up of 625 interlaced lines and is displayed at a rate of 25 frames per second. However, due to the way SECAM processes color information, it is not compatible with the German PAL video format standard. This page primarily discusses the SECAM colour encoding system. The articles on broadcast television systems and analog television further describe frame rates, image resolution, and audio modulation. SECAM video is composite video because the luminance and chrominance are transmitted together as one signal.
Y′UV, also written YUV, is the color model found in the PAL analogue color TV standard. A color is described as a Y′ component (luma) and two chroma components U and V. The prime symbol (') denotes that the luma is calculated from gamma-corrected RGB input and that it is different from true luminance. Today, the term YUV is commonly used in the computer industry to describe colorspaces that are encoded using YCbCr.
Chroma subsampling is the practice of encoding images by implementing less resolution for chroma information than for luma information, taking advantage of the human visual system's lower acuity for color differences than for luminance.
ITU-R Recommendation BT.601, more commonly known by the abbreviations Rec. 601 or BT.601, is a standard originally issued in 1982 by the CCIR for encoding interlaced analog video signals in digital video form. It includes methods of encoding 525-line 60 Hz and 625-line 50 Hz signals, both with an active region covering 720 luminance samples and 360 chrominance samples per line. The color encoding system is known as YCbCr 4:2:2.
YIQ is the color space used by the analog NTSC color TV system. The name Color Space stands for the following aliases suite or set & pool of reduced number of different colors selected thoroughly for sustaining quality of image above basic need & - simultaneously - for distributing limited spectre economical way. I stands for in-phase, while Q stands for quadrature, referring to the components used in quadrature amplitude modulation. Other TV systems used different color spaces, such as YUV for PAL or YDbDr for SECAM. Later digital standards use the YCbCr color space. These color spaces are all broadly related, and work based on the principle of adding a color component named chrominance, to a black and white image named luma.
PALplus is an analogue television broadcasting system aimed to improve and enhance the PAL format by allowing 16:9 aspect ratio broadcasts, while remaining compatible with existing television receivers, defined by International Telecommunication Union (ITU) recommendation BT.1197-1. Introduced in 1993, it followed experiences with the HD-MAC and D2-MAC, hybrid analogue-digital widescreen formats that were incompatible with PAL receivers. It was developed at the University of Dortmund in Germany, in cooperation with German terrestrial broadcasters and European and Japanese manufacturers. The system had some adoption across Europe during the late 1990s and helped introduce widescreen TVs in the market, but never became mainstream.
YDbDr, sometimes written , is the colour space used in the SECAM analog colour television broadcasting standard. It is very close to YUV and its related colour spaces such as YIQ, YPbPr and YCbCr.
HD-MAC was a broadcast television standard proposed by the European Commission in 1986, as part of Eureka 95 project. It belongs to the MAC - Multiplexed Analogue Components standard family. It is an early attempt by the EEC to provide High-definition television (HDTV) in Europe. It is a complex mix of analogue signal, multiplexed with digital sound, and assistance data for decoding (DATV). The video signal was encoded with a modified D2-MAC encoder.
Analog high-definition television has referred to a variety of analog video broadcast television systems with various display resolutions throughout history.
In video, luma represents the brightness in an image. Luma is typically paired with chrominance. Luma represents the achromatic image, while the chroma components represent the color information. Converting R′G′B′ sources into luma and chroma allows for chroma subsampling: because human vision has finer spatial sensitivity to luminance differences than chromatic differences, video systems can store and transmit chromatic information at lower resolution, optimizing perceived detail at a particular bandwidth.
MUSE, commercially known as Hi-Vision was a Japanese analog high-definition television system, with design efforts going back to 1979.
In television electronics, A-MAC carries digital information: sound, and data-teletext on an FM subcarrier at 7 MHz. Since the vision bandwidth of a standard MAC signal is 8.4 MHz, the horizontal resolution on A-MAC has to be reduced to make room for the 7 MHz carrier. A-MAC has not been used in service.
B-MAC is a form of analog video encoding, specifically a type of Multiplexed Analogue Components (MAC) encoding. MAC encoding was designed in the mid 80s for use with Direct Broadcast Satellite systems. Other analog video encoding systems include NTSC, PAL and SECAM. Unlike the FDM method used in those, MAC encoding uses a TDM method. B-MAC was a proprietary MAC encoding used by Scientific-Atlanta for encrypting broadcast video services; the full name was "Multiple Analogue Component, Type B".
C-MAC is the television technology variant approved by the European Broadcasting Union (EBU) for satellite transmissions. The digital information is modulated using 2-4PSK, a variation of quadrature PSK where only two of the phaser angles (±90°) are used.
Among the family of MAC or Multiplexed Analogue Components systems for television broadcasting, D-MAC is a reduced bandwidth variant designed for transmission down cable.
D2-MAC is a satellite television transmission standard, a member of Multiplexed Analogue Components family. It was created to solve D-MAC's bandwidth usage by further reducing it, allowing usage of the system on cable and satellite broadcast. It could carry four high quality sound channels or eight lower quality audio channels. It was adopted by Scandinavian, German and French satellite broadcasts. The system was used until July 2006 in Scandinavia and until the mid-1990s for German and French sound channels.
The color killer is an electronic stage in color TV receiver sets which acts as a cutting circuit to cut off color processing when the TV set receives a monochrome signal.
The EBU colour bars are a television test card used to check if a video signal has been altered by recording or transmission, and what adjustments must be made to bring it back to specification. It is also used for setting a television monitor or receiver to reproduce chrominance and luminance information correctly. The EBU bars are most commonly shown arranged side-by-side in a vertical manner, though some broadcasters – such as TVP in Poland, and Gabon Télévision in Gabon – were known to have aired a horizontal version of the EBU bars.
