Information about Television Systems Before 1940

A number of experimental and broadcast pre World War II television systems were tested. The first ones were mechanical based (mechanical TV) and of very low resolution, sometimes with no sound. Later TV systems were electronic (electronic TV).

France

• France 1932 (mechanical): 60 lines, 12.5 fps, 3:7 vertical aspect ratio, vertical scanning ~35x60 pixels per frame, sound, live images
• France 1935: 375 lines, abandoned 1936
• France 1935 (electronic): 441 lines, 25 fps, line frequency 11025 Hz, discontinued in 1956. (Monitored in the UK during WWII to gather intelligence information from occupied France) Vision 46.0MHz Sound 42.0MHz.
• France 1937 (electronic): 455 lines, abandoned 1940
• France 1939 (electronic): 405 lines, abandoned 1940

Belgium

• Belgium 1932 (mechanical): 30 lines, 12.5 & 16.6 fps, 4:3 horizontal aspect ratio, ~40x30 pixels per frame, sound, talking movies

Germany

• Paul Gottlieb Nipkow 1884: 24 lines.
• Nipkow was granted a patent, but no practical TV transmissions came out of Nipkow's work.
• The Nipkow system may be the first system for transmitting television.

(Note that Nipkow was a German of Kashubian origin; the town in which he was born is now in Poland).

• Germany 1928: 96 lines (city experimented in not found)
• Berlin 1932 (mechanical): 30 lines, 12.5 fps, 4:3 horizontal aspect ratio, ~40x30 pixels per frame, test movies and live images
• Koningswusterhausen 1932 (mechanical): 39 lines, 12.5 fps, 4:3 horizontal aspect ratio, ~31x30 pixels per frame, movies
• Doberitz 1932 (mechanical): 48 lines, 25 fps, 4:3 horizontal aspect ratio, ~64x48 pixels per frame, sound, talking movies
• Berlin R.P.Z. 1932 (mechanical): 60 lines, 25 fps, 4:3 horizontal aspect ratio, ~83x60 pixels per frame, test movies and live images
• Germany 1932: 90 lines
• Germany 1935: 180 lines
• Germany 1939 (Einheitsempfänger E 1): 441 lines, 25 fps, line frequency 11025 Hz. Vision 46.0MHz Sound 43.2MHz.

Netherlands

• Netherlands 1930's: 441 lines, 25 fps, line frequency 11025 Hz

Poland

• Warsaw 1937 (mechanical): 120 lines, test movies and live images from a studio
• Electronic TV (between 343 and 400+ lines) was under development and was demonstrated during the Radio Exhibition in August 1939, work stopped due to outbreak of WW2

Switzerland

• Switzerland 1932 (mechanical): 30 lines, 16.6 fps, 4:3 horizontal aspect ratio, ~40x30 pixels per frame, test movies and live images

Italy

During the 1930s there were also experimental transmissions from the Vatican - further details unknown

• Italy 1932 (mechanical): 60 lines, 20 fps, 4:3 horizontal aspect ratio, ~45x60 pixels per frame, test movies and live images
• Italy 1939 (electronic): 441 lines, 21 Fps, 4:3 horizontal aspect ratio, regular service from Rome and Milan. 2kW transmission power on VHF 50MHz

UK

Mechanical

• England 1926 (Baird mechanical): 30 lines, 5 fps, black-and-white experimental transmissions
• England 1928 (Baird mechanical): 30 lines, 5 fps, first experimental color TV transmissions
• London 1932 (Baird mechanical) : 30 lines, 12.5 fps, 3:7 vertical aspect ratio, vertical scanning, ~70x30 pixels per frame, sound, live TV from studio
• England 1936 (Baird): 240 lines, 25 fps, line frequency 6000 Hz, used from November 1936 to February 1937

Electronic

• UK (1936, EMI): 405 lines / 50 Hz. Used from November 1936 to 1985.
• The EMI 405 lines system (1938-1939) was the first to have an ITU System Letter Designation.
• The EMI system is officially known as System-A. As the EMI system predates PAL, there is no PAL designator in the ITU television system table.

USSR

• USSR 1932 (mechanical): 30 lines, 12.5 fps, 4:3 horizontal aspect ratio, ~40x30 pixels per frame, test movies and live images

North America

• USA 1933: 240 lines
• USA 1936: 343 lines; limited public demonstrations in New York City (RCA) and Philadelphia (Philco). Field tests in Los Angeles used various line systems, but adopted RCA's 441-line system by 1938.
• USA 1938-9: First TV receivers sold on a very limited basis, mostly in New York. Manufactures included RCA, GE, DuMont, and Andrea.
• USA 1937-1941: 441 lines @ 30 f.p.s.(RCA) and 605 lines (Proposed by Philco), both replaced by 525 line System-M on July 1, 1941 when the FCC issued the first commercial licenses.

How and why particular line rates were chosen

Because an interlaced system requires accurate positioning of scanning lines it is important to make sure that the horizontal and vertical timebases are in a precise ratio. This is accomplished by passing the one through a series of electronic divider circuits to produce the other. Each division is by a prime number. Therefore there has to be a straightforward mathematical relationship between the line and field frequencies, the latter being derived by dividing down from the former. Technology constraints of the 1930s meant that this division process could only be done using small integers, preferably no greater than 7, for good stability. The number of lines was odd because of 2:1 interlace. The British 405 line system for example used a vertical frequency of 50 Hz (Standard AC mains supply frequency in Britain) and a horizontal one of 10,125Hz (50 × 405 ÷ 2)

• 2 × 3 × 3 × 5 Gives 90 (not interlaced)
• 2 × 2 × 2 × 2 × 2 × 3 Gives 96 (not interlaced)
• 2 × 2 × 3 × 3 × 5 Gives 180 (not interlaced)
• 2 × 2 × 2 × 2 × 3 × 5 Gives 240 (Used for the experimental Baird transmissions in England -not interlaced)
• 3 × 3 × 3 × 3 × 3 Gives 243
• 7 × 7 × 7 Gives 343 (Early North American system also used in Poland before WW2)
• 3 × 5 × 5 × 5 Gives 375
• 3 × 3 × 3 × 3 × 5 Gives 405 (Used in Britain Ireland and Hong Kong before 1985)
• 2 × 2 × 2 × 5 × 11 Gives 440 (not interlaced)
• 3 × 3 × 7 × 7 Gives 441 (Used by RCA in North America America before the 525 standard was adopted and widely used before WW2 in Continental Europe with different frame rates )
• 2 × 3 × 3 × 5 × 5 Gives 450
• 5 × 7 × 13 Gives 455 (Used in France before WW2)
• 3 × 5 × 5 × 7 Gives 525 (A compromise between the RCA and Philco systems Still used today In America and parts of Asia)
• 3 × 3 × 3 × 3 × 7 produces 567 (used for a while after WW2 in the Netherlands)
• 5 × 11 × 11 Gives 605 (Used experimentally by Philco in North America before the 525 standard was adopted)
• 5 × 5 × 5 × 5 gives 625 (Still used today in most parts of the world)
• 3 × 3 × 7 × 13 Gives 819 (Used in France from the 1950’s till the 1980's)

Even some digital TV line rates (i.e. 480 and 576) are based on the number of active lines in the 525 and 625 analogue video standards which preceded them.

How and why particular frame/field rates were chosen

Since the mid-1930s it has been standard practice to use a field frequency equal to or a submultiple of the AC mains electric supply frequency 50 Hz in most countries (60 Hz in others) because studio lighting generally uses alternating current lamps and if these were not synchronized with the field frequency, an unwelcome strobe effect could appear on TV pictures. Secondly the smoothing (filtering) of power supply circuits in early TV receivers was rather poor and ripple superimposed on the DC could cause visual interference. If the picture was locked to the mains frequency, this interference would at least be static on the screen and thus less obtrusive. By the 1930s most countries had standardized their public electricity supplies on either 50Hz or 60Hz and this heavily influenced the choice of frame rate (12.5 25 or 30 fps)

Other considerations

The bandwidth required to transmit a television signal increases as the field rate and particularly as the line rate increases. In the interests of economic use of the available radio frequency spectrum, it is important that the bandwidth of the TV signals does not become too large; a more pressing consideration in the 1930s was that given the limits of the technology of the day, wide-bandwidth signals were very difficult to handle within transmitter, receiver and antenna circuitry. Thus while it may have been desirable to maximize picture quality by using very high line and frame rates, in practice there were limits to what could be used.

The THEORETICAL bandwidth requirements of the different standards are as follows

• (number of lines * frame rate) * (number of lines * aspect ratio) /2
• 405 line (405 * 25) * (405 * 4/3) /2 = 2733750 Hz or 2.75 MHz (5:4 aspect ratio pre-1950)
• 525 line (525 * 30) * (525 * 4/3) /2 = 5512500 Hz or 5.52 MHz (29.98 Hz field rate with Colour NTSC)
• 625 line (625 * 25) * (625 * 4/3) /2 = 6510417 Hz or 6.51 MHz
• 819 line (819 * 25) * (819 * 4/3) /2 = 11179350 Hz or 11.2 MHz

In practice most broadcast TV systems use slightly less video bandwidth sacrificing some horizontal resolution in the process.

See also

• Timeline of the BBC
• History of television
• Timeline of the introduction of television in countries
• Timeline of the introduction of colour television in countries
• Geographical usage of television
• Moving image formats
• Oldest radio station
• List of experimental television stations
• Narrow-bandwidth television
• Oldest television station
• Early television stations
• Television systems before 1940

Individual television stations

• WRGB
• WNBC-TV
• WCBS-TV
• KCBS-TV
• BBC / BBC Television

Broadcast television systems

• Television systems before 1940
• NTSC
• PAL
• SECAM

Specific Television Articles

• Mechanical television
• Oldest television station
• 405 lines
• 819 lines
• NBTV
• Display resolution

[ edit ] Video formats
Analog broadcast
525 lines: NTSC | NTSC-J | PAL-M
625 lines: PAL | PAL-N | PALplus | SECAM
Defunct systems: Pre-1940 | 405 lines | 819 lines | Baird-Nipkow | MAC | MUSE
Multichannel audio: BTSC (MTS) | NICAM-728 | Zweiton (A2, IGR)
Hidden signals: Captioning | Teletext | CGMS-A | GCR | PDC | VBI | VEIL | VITC | WSS | XDS
Digital broadcast
Interlaced: SDTV (480i, 576i) | HDTV (1080i)
Progressive: LDTV (240p, 288p, 1seg) | EDTV (480p, 576p) | HDTV (720p, 1080p)
Digital TV standards: MPEG-2: ATSC, DVB, ISDB | MPEG-4: SBTVD
Multichannel audio: AAC (5.1) | Musicam | PCM | LPCM
Hidden signals: Captioning | Teletext | (CPCM/Broadcast flag) | AFD | EPG
Digital cinema: UHDV (2540p, 4320p) | DCI | 22.2 audio
Technical issues: | MPEG transport | Standards conversion | Video processing | VOD

Allied powers:
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...et al. Axis powers:
 Germany
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Television (often abbreviated to TV, T.V., or more recently, tv; sometimes called telly, the tube, boob tube, or idiot box in British English) is a widely used telecommunication system for broadcasting and receiving moving pictures
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Mechanical television was a television system that used mechanical or electromechanical devices to capture and display images. However, the images themselves were usually transmitted electronically and via radio waves.
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FPS has several meanings:

In units of measurement:

• Foot-pound-second, the imperial units system of measurement
• Feet per second, an Imperial unit for speed
• Frames per second, used for measuring the frame speed in a moving image

In media
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The aspect ratio of a two-dimensional shape is the ratio of its longer dimension to its shorter dimension. It is also applied to two characteristic dimensions of a three-dimensional shape, especially for the longest and shortest 'axes' or for symmetrical objects (e.g.
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pixel (short for picture element, using the common abbreviation "pix" for "pictures") is a single point in a graphic image. Each such information element is not really a dot, nor a square, but an abstract sample.
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Paul Julius Gottlieb Nipkow (22 August 1860, Lauenburg, Pomerania - 24 August 1940, Berlin) was a German technician and inventor.

Beginnings

While at school in Neustadt, East Pomerania, Nipkow experimented in telephony and the transmission of moving pictures.
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Anthem
Inno e Marcia Pontificale   (Italian)
Hymn and Pontifical March
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Baird may refer to:

In places:

• Baird, Texas, a US city
• Baird, a local government ward within Hastings Borough Council in the county of East Sussex, England

Other:

• Robert W. Baird & Co.

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The 405-line monochrome analogue television broadcasting system was the first electronic television system to be used in regular broadcasting. It was introduced with the BBC Television Service in 1936, suspended for the duration of World War II, and remained in operation in the UK
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The 405-line monochrome analogue television broadcasting system was the first electronic television system to be used in regular broadcasting. It was introduced with the BBC Television Service in 1936, suspended for the duration of World War II, and remained in operation in the UK
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Itu is a municipality in the state of São Paulo in Brazil. The population in 2004 is 149,758 and the area is 641.68 km². The elevation is 583 m. This place name comes from the Tupi language.
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PAL, short for Phase Alternating Line, is a colour encoding system used in broadcast television systems in large parts of the world. Other common analogue television systems are SECAM and NTSC.
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City of New York
New York City at sunset

Flag
Seal
Nickname: The Big Apple, Gotham, The City that Never Sleeps
Location in the state of New York
Coordinates:
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RCA, formerly an acronym for the Radio Corporation of America, is now a trademark owned by Thomson SA through RCA Trademark Management S.A., a company owned by Thomson.
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Nickname: "City of Brotherly Love", "The City that Loves you Back", "Cradle of Liberty", "The Quaker City", "The Birthplace of America", "Philly".
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Philco, the Philadelphia Storage Battery Company (formerly known as the Spencer Company and later the Helios Electric Company), was a pioneer in early radio and television and former employer of Philo Farnsworth, inventor of cathode ray tube television.
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City of Los Angeles

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Nickname: The City of Angels, L.A.
Location within Los Angeles County in the state of California
Coordinates:
State
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RCA, formerly an acronym for the Radio Corporation of America, is now a trademark owned by Thomson SA through RCA Trademark Management S.A., a company owned by Thomson.
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Ge (IPA: /jeː/) was the second-person, plural, personal pronoun (subject case) in Old English.

Modern scholars write this word ġē, to mark that the g
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DuMont Laboratories began in 1931, by Allen B. DuMont. The company began researching the cathode ray tubes that would be used for television.

In 1938, they began manufacturing televisions.
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Andrea is a given name common in many parts of the world:

• In the Americas, Australia, and some parts of Europe, Andrea is used as a woman's name, as the feminine form of Andrew or Andreas or Andre.

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Federal Communications Commission

Logo

The FCC's official seal
Agency overview
Formed June 19, 1934
Preceding Agencies Federal Radio Commission
 

Annual Budget

Agency Executive
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Interlace is a technique of improving the picture quality of a video signal without consuming any extra bandwidth. It was invented by RCA engineer Randall C. Ballard in the 1930s.
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In mathematics, a prime number (or a prime) is a natural number which has exactly two distinct natural number divisors: 1 and itself. An infinitude of prime numbers exists, as demonstrated by Euclid in about 300 BC.
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Hz or hz may mean:

• Herero language (ISO 639 alpha-2, hz)
• Hertz, unit of frequency

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HZ, in all capitals, can stand for:

• Hazard
• Herpes Zoster
• Horizons, a computer game

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Digital television (DTV) is a telecommunication system for broadcasting and receiving moving pictures and sound by means of digital signals, in contrast to analog signals used by analog (traditional) TV.
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Bandwidth is the difference between the upper and lower cutoff frequencies of, for example, a filter, a communication channel, or a signal spectrum, and is typically measured in hertz.
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1922

18 October - The British Broadcasting Company is formed.

14 November - First BBC broadcasts from London (station 2LO).
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The History of television technology can be divided along two lines: those developments that depended upon both mechanical and electronic principles, and those which are purely electronic.
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