Analog high-definition television

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Analog high-definition television has referred to a variety of analog video broadcast television systems with various display resolutions throughout history.

Contents

Before 1940

On 2 November 1936 the BBC began transmitting the world's first public regular analog "high definition" television service from the Victorian Alexandra Palace in north London. [1] It therefore claims to be the birthplace of television broadcasting as we know it today. The UK's 405-line system introduced in 1936 was described as "high definition"; however, this was in comparison with the early 30-line (largely) experimental system from the 1920s, and would not be considered high definition by modern standards.

John Logie Baird, Philo T. Farnsworth, and Vladimir Zworykin had each developed competing TV systems, but resolution was not the issue that separated their substantially different technologies, it was patent interference lawsuits and deployment issues given the tumultuous financial climate of the late 1920s and 1930s. Most patents were expiring by the end of World War II leaving no worldwide standard for television. The standards introduced in the early 1950s stayed for over half a century.

French 819-line system

819-line was a monochrome TV system developed and used in France [2] [3] as television broadcast resumed after World War II. Transmissions started in 1949 and were active up to 1985, although limited to France, Belgium and Luxembourg. [4] It is associated with CCIR System E and F. [4]

Despite some attempts to create a color SECAM version of the 819-line system, [2] France gradually abandoned the system in favor of the Europe-wide standard of 625-lines with the final 819-line transmissions taking place in Paris from the Eiffel Tower on 19 July 1983. [5] Tele Monte Carlo in Monaco were the last broadcasters to transmit 819-line television, closing down their transmitter in 1985.

Multiple sub-nyquist sampling Encoding system (MUSE)

Japan had the earliest working HDTV system, with design efforts going back to 1979. The country began broadcasting wideband analog high-definition video signals in the late 1980s using an interlaced resolution of 1035 or 1080-lines active (1035i) and 1125-lines total supported by the Sony HDVS line of equipment.

The Japanese system, developed by NHK Science & Technology Research Laboratories in the 1980s, employed filtering tricks to reduce the original source signal to decrease bandwidth utilization. MUSE was marketed as "Hi-Vision" by NHK. Japanese broadcast engineers rejected conventional vestigial sideband broadcasting to allow transmitting a HD signal on a tighter bandwidth. It was decided early on that MUSE would be a satellite broadcast format as Japan economically supports satellite broadcasting.

In the typical setup, three picture elements on a line were actually derived from three separate scans. Stationary images were transmitted at full resolution. However, as MUSE lowers the horizontal and vertical resolution of material that varies greatly from frame to frame, moving images were blurred in a manner similar to using 16 mm movie film for HDTV projection. In fact, whole-camera pans would result in a loss of 50% of horizontal resolution. Shadows and multipath still plague this analog frequency modulated transmission mode.

MUSE's "1125-lines" are an analog measurement, which includes non-video "scan lines" during which a CRT's electron beam returns to the top of the screen to begin scanning the next field. Only 1035-lines have picture information. [6] Digital signals count only the lines (rows of pixels) of the picture makeup as there are no other scanning lines (though conversion to an analogue format will introduce them), so NTSC's 525-lines become 480i, and MUSE would be 1035i.

Japan has since switched to a digital HDTV system based on ISDB; the original MUSE-based BS Satellite channel 9 (NHK BS Hi-vision) ended transmitting on November 30, 2007, [7] moving to BS-digital channel 103.

Subsampling lives on in modern MPEG systems based on JPEG coding, as JPEG offers Chroma sub-sampling. High quality HD television has a sampling structure approximating 4:2:1 (Luma : Chroma : Saturation) for reference images (I-Frames), though 4:0.75:0.65 is probably typical for multi-channel delivery.

HD-MAC

HD-MAC was a proposed television standard by the European Commission in 1986 (MAC standard). It was an early attempt by the EEC to provide HDTV in Europe. It was a complex mix of analog signal (Multiplexed Analog Components) multiplexed with digital sound. The video signal (1,250 (1,152 visible) lines/50 frames in 16:9 aspect ratio) was encoded with a modified D2-MAC encoder.

HD-MAC test pattern similar to the B-MAC test pattern Multiplexed Analogue Components transmission (simulation).jpg
HD-MAC test pattern similar to the B-MAC test pattern

For the 1992 Summer Olympics, experimental HD-MAC broadcasting took place. 100 HD-MAC receivers (in that time, retroprojectors) in Europe were used to test the capabilities of the standard. This project was financed by the European Union (EU). The PAL-converted signal was used by mainstream broadcasters such as SWR, BR and 3Sat.

The HD-MAC standard was abandoned in 1993, and since then all EU and EBU efforts have focused on the DVB system (Digital Video Broadcasting), which allows both SDTV and HDTV.

See also

The analog TV systems these systems were meant to replace

Related standards

Electronovision, a video tape movie production technique based on the 819-line system.

Related Research Articles

<span class="mw-page-title-main">Digital television</span> Television transmission using digital encoding

Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative advancement and represented the first significant evolution in television technology since color television in the 1950s. Modern digital television is transmitted in high-definition television (HDTV) with greater resolution than analog TV. It typically uses a widescreen aspect ratio in contrast to the narrower format (4:3) of analog TV. It makes more economical use of scarce radio spectrum space; it can transmit up to seven channels in the same bandwidth as a single analog channel, and provides many new features that analog television cannot. A transition from analog to digital broadcasting began around 2000. Different digital television broadcasting standards have been adopted in different parts of the world; below are the more widely used standards:

<span class="mw-page-title-main">NTSC</span> Analog television system

NTSC is the first American standard for analog television, published and adopted in 1941. In 1961, it was assigned the designation System M. It is also known as EIA standard 170.

<span class="mw-page-title-main">Interlaced video</span> Technique for doubling the perceived frame rate of a video display

Interlaced video is a technique for doubling the perceived frame rate of a video display without consuming extra bandwidth. The interlaced signal contains two fields of a video frame captured consecutively. This enhances motion perception to the viewer, and reduces flicker by taking advantage of the characteristics of the human visual system.

<span class="mw-page-title-main">Chroma subsampling</span> Practice of encoding color images

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.

Broadcasttelevision systems are the encoding or formatting systems for the transmission and reception of terrestrial television signals.

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.

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.

<span class="mw-page-title-main">720p</span> Video resolution

720p is a progressive HD signal format with 720 horizontal lines/1280 columns and an aspect ratio (AR) of 16:9, normally known as widescreen HD (1.78:1). All major HD broadcasting standards include a 720p format, which has a resolution of 1280×720p.

1080i is a term used in high-definition television (HDTV) and video display technology. It means a video mode with 1080 lines of vertical resolution. The "i" stands for interlaced scanning method. This format was once a standard in HDTV. It was particularly used for broadcast television. This is because it can deliver high-resolution images without needing excessive bandwidth. This format is used in the SMPTE 292M standard.

High-definition video is video of higher resolution and quality than standard-definition. While there is no standardized meaning for high-definition, generally any video image with considerably more than 480 vertical scan lines or 576 vertical lines (Europe) is considered high-definition. 480 scan lines is generally the minimum even though the majority of systems greatly exceed that. Images of standard resolution captured at rates faster than normal, by a high-speed camera may be considered high-definition in some contexts. Some television series shot on high-definition video are made to look as if they have been shot on film, a technique which is often known as filmizing.

<span class="mw-page-title-main">1080p</span> Video mode

1080p is a set of HDTV high-definition video modes characterized by 1,920 pixels displayed across the screen horizontally and 1,080 pixels down the screen vertically; the p stands for progressive scan, i.e. non-interlaced. The term usually assumes a widescreen aspect ratio of 16:9, implying a resolution of 2.1 megapixels. It is often marketed as Full HD or FHD, to contrast 1080p with 720p resolution screens. Although 1080p is sometimes referred to as 2K resolution, other sources differentiate between 1080p and (true) 2K resolution.

<span class="mw-page-title-main">Multiplexed Analogue Components</span> 1980s analog television standard

Multiplexed Analogue Components (MAC) was an analog television standard where luminance and chrominance components were transmitted separately. This was an evolution from older color TV systems where there was interference between chrominance and luminance.

MUSE, commercially known as Hi-Vision was a Japanese analog high-definition television system, with design efforts going back to 1979.

<span class="mw-page-title-main">819 line</span> 1940s French analogue high-definition television system

819-line was an analog monochrome TV system developed and used in France as television broadcast resumed after World War II. Transmissions started in 1949 and were active up to 1985, although limited to France, Belgium and Luxembourg. It is associated with CCIR System E and F.

Television standards conversion is the process of changing a television transmission or recording from one video system to another. Converting video between different numbers of lines, frame rates, and color models in video pictures is a complex technical problem. However, the international exchange of television programming makes standards conversion necessary so that video may be viewed in another nation with a differing standard. Typically video is fed into video standards converter which produces a copy according to a different video standard. One of the most common conversions is between the NTSC and PAL standards.

High-definition television (HDTV) describes a television or video system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since at least 1933; in more recent times, it refers to the generation following standard-definition television (SDTV). It is the standard video format used in most broadcasts: terrestrial broadcast television, cable television, satellite television.

<span class="mw-page-title-main">525 lines</span> 1940s American analog standard-definition television resolution standard

525-line is an American standard-definition television resolution used since July 1, 1941, mainly in the context of analog TV broadcast systems. It consists of a 525-line raster, with 480 lines carrying the visible image at 30 interlaced frames per second. It was eventually adopted by countries using 60 Hz utility frequency as TV broadcasts resumed after World War II. With the introduction of color television in the 1950s, it became associated with the NTSC analog color standard.

<span class="mw-page-title-main">Ultra-high-definition television</span> Television formats beyond HDTV

Ultra-high-definition television today includes 4K UHD and 8K UHD, which are two digital video formats with an aspect ratio of 16:9. These were first proposed by NHK Science & Technology Research Laboratories and later defined and approved by the International Telecommunication Union (ITU).

Clear-Vision is a Japanese EDTV television system introduced in the 1990s, that improves audio and video quality while remaining compatible with the existing broadcast standard. Developed to improve analog NTSC, it adds features like progressive scan, ghost cancellation and widescreen image format. A similar system named PALPlus was developed in Europe with the goal of improving analog PAL broadcasts.

References

  1. ↑ http://www.teletronic.co.uk/tvera.htm Archived 2011-08-13 at the Wayback Machine Teletronic – The Television History Site
  2. 1 2 Stout, Andy. "France had a national HD TV system as far back as 1949". www.redsharknews.com.
  3. ↑ Worswick, T. (March 11, 1959). "The B.B.C. Television Standards Converter". Journal of the SMPTE. 68 (3): 130–135. doi:10.5594/J14437. Archived from the original on June 16, 2018 – via IEEE Xplore.
  4. 1 2 Birkinshaw, AUTHOR: Douglas C. "New television standards: effect on British television". Transdiffusion.
  5. ↑ "Histoire de la télévision : une exception française ?". La Revue des Médias.
  6. ↑ Lewis, Geoff (1996). Communications Technology Handbook. CRC Press. ISBN   0-240-51461-0.
  7. ↑ "MIC(Press Release-Telecom)". www.soumu.go.jp. Retrieved 18 April 2018.


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