TVE test card
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The TVE colour test card (Spanish: Carta de ajuste color TVE) was an electronic analogue TV
test card A test card, also known as a test pattern or start-up/closedown test, is a television test signal, typically broadcast at times when the transmitter is active but no program is being broadcast (often at sign-on and sign-off). Used since the ear ...
adopted by
Televisión Española Televisión Española (acronym TVE, branded tve, "Spanish Television") is Spain's national state-owned public television broadcaster and the oldest regular television service in the country. It was also the first regular television service in ...
(TVE - Spanish national television) with the introduction of
PAL Phase Alternating Line (PAL) is a colour encoding system for analogue 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 (25 ...
colour broadcasts in 1975.* It is notable for its unique design, created by the Danish engineer Finn Hendil in 1973, under the supervision of Erik Helmer Nielsen at the
Philips Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters i ...
TV & Test Equipment laboratory in
Brøndby Municipality Brøndby Kommune (), a municipality ( da, kommune) in the former Copenhagen County (now Region Hovedstaden), is on the east coast of the island of Zealand (''Sjælland'') in eastern Denmark. The municipality covers an area of , and has a total p ...
near
Copenhagen Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ar ...
, the same team that developed the popular
Philips PM5544 The Philips PM5544 is a television pattern generator, most commonly used to provide a television station with a complex test card commonly referred to as a Philips Pattern or PTV Circle pattern. The content and layout of the pattern was designed b ...
test pattern. It replaced a previous black and white version developed by Eduardo Gavilán. The test card was considered to be part of the regular TV schedule, figuring among daily program listings published in newspapers and magazines. It was said to be the most viewed program in some days, because people watched the test card while waiting for broadcasts to start in the afternoon. It was also relevant in the context of general work strikes, where the test card was sometimes broadcast in place of regular programming, marking it a visible sign of the strike's success. It was used on several TVE channels, like '' La Primera'', '' La 2'', '' Canal Clásico'', ''
Teledeporte Teledeporte (TDP) is a Spanish free-to-air television channel owned and operated by Televisión Española (TVE), the television division of state-owned public broadcaster Radiotelevisión Española (RTVE). It is the corporation's sports televis ...
'' or ''
TVE Internacional TVE Internacional is a Spanish satellite free-to-air and pay television channel owned and operated by Televisión Española (TVE), the television division of state-owned public broadcaster Radiotelevisión Española (RTVE). It is the corporati ...
''. With the start of continuous 24-hour broadcasting on TVE's channels, the test card was phased out. It stopped being broadcast on ''La Primera'' in 1996 and on ''La 2'' in the early morning hours of 6 January 2001, although it continued to be broadcast sporadically on ''Teledeporte ''and ''TVE Internacional'' until 2005.


Operation and features

As Televisión Española adopted the PAL colour system in 1975, the test card has specific elements that allow proper colour adjustments. Being a creation of the same team behind the Philips PM5544 test card, it has many elements in common with it (like colour and grey bars or castellations), but introduces some differences (for example, different resolution gratings and coloured background rectangle and circle).


Castellations

The alternating white and black boxes around the perimeter are called castellations. They are used to set
overscan Overscan is a behaviour in certain television sets, in which part of the input picture is shown outside of the visible bounds of the screen. It exists because cathode-ray tube (CRT) television sets from the 1930s through to the early 2000s were h ...
(castellations should be visible) and check for low frequency response of the entire transmission chain.


Grid

The background features a grid composed of perfect squares of 100% intensity white lines. This element allows: * Verify image geometry (horizontal and vertical size and linearity,
cushion A cushion is a soft bag of some ornamental material, usually stuffed with wool, hair, feathers, polyester staple fiber, non-woven material, cotton, or even paper torn into fragments. It may be used for sitting or kneeling upon, or to soften th ...
or
barrel distortion In geometric optics, distortion is a deviation from rectilinear projection; a projection in which straight lines in a scene remain straight in an image. It is a form of aberration in optical systems, optical aberration. Radial distortion Al ...
effects); * Adjust CRT convergence (the three
electron gun An electron gun (also called electron emitter) is an electrical component in some vacuum tubes that produces a narrow, collimated electron beam that has a precise kinetic energy. The largest use is in cathode-ray tubes (CRTs), used in nearly ...
s, one for each
primary color A set (mathematics), set of primary colors or primary colours (see American and British English spelling differences#-our, -or, spelling differences) consists of colorants or colored lights that can be mixed in varying amounts to produce a gamu ...
, need to target the same place); * Adjust CRT focus; * Check CRT color purity when displaying the 50% intensity gray background.


Rectangle

This element is composed of an orange rectangle, framed with a white line and located at the image center. It allows for: * Checking proper
chrominance Chrominance (''chroma'' or ''C'' for short) is the signal used in video systems to convey the color information of the picture (see YUV color model), separately from the accompanying luma signal (or Y' for short). Chrominance is usually represente ...
delay, essential for good PAL system operation; * Visualizing low frequency image distortions; * Adjusting maximum color saturation. Signal values of this element are:


Circle

This element is composed of a light blue circle, also located at the center of the image. With a diameter of 512 lines, it overlaps the rectangle mentioned previously. The circle provides a quick overview of image geometry. Signal values of this element are:


Box

Located at the top of the circle and composed of 100% white lines, it allows to verify the low frequency response of the transmission chain.


Colour bars

Inside the circle there's a section of
colour bars SMPTE color bars are a television test pattern used where the NTSC video standard is utilized, including countries in North America. The Society of Motion Picture and Television Engineers (SMPTE) refers to the pattern as Engineering Guideline ( ...
with 75% amplitude and 100% saturation (
EBU color bars The EBU colour bars is 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 ...
), that allow checking chrominance parameters on a
vectorscope A vectorscope is a special type of oscilloscope used in both audio and video applications. Whereas an oscilloscope or waveform monitor normally displays a plot of signal vs. time, a vectorscope displays an X-Y plot of two signals, which can r ...
or
waveform monitor A waveform monitor is a special type of oscilloscope used in television production applications. It is typically used to measure and display the level, or voltage, of a video signal with respect to time. The level of a video signal usually corre ...
. The signal values of these bars are:


Centre Grid

This element is composed of 100% white lines located at the center of the image, between the colour bars and the greysscale. It helps with image centring adjustment and allow checking for CRT convergence at the centre of the screen.


Greyscale Bars

Beneath the colour bars there's a greyscale bar with six steps. This allows checking
gamma correction Gamma correction or gamma is a nonlinear operation used to encode and decode luminance or tristimulus values in video or still image systems. Gamma correction is, in the simplest cases, defined by the following power-law expression: : V_\text = ...
of the television receiver, and linearity response of the transmission chain. The brightness value of each steps varies with a ratio of 20%, as follows:


Grating Bars

Located within the circle, the gratings are composed of alternating white and black lines. Horizontal frequency response ( horizontal resolution) can be determined by five frequency gratings of 0.5, 1.25, 2.25, 4.2 and 4.8
MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...
. The last two gratings must show interference from the 4.43 MHz PAL colour carrier.


Pulse Signal

A pulse signal bar is placed under the frequency gratings, consisting of a black rectangle with a white vertical line, corresponding to a 2T pulse. This signal shows the status of the transmission chain at high frequencies, as well as ghosting due to signal echoes.


Station Identification

Other elements like TV network identification ("TVE","La Primera","TVE2","Teleporte","Canal Clásico","TVE Internacional"), specific TV channel logos or a clock were usually added to the test pattern.


See also

*
Philips PM5540 The Philips PM5540 was an early electronically-generated, monochrome test card that is considered to be a black-and-white predecessor of the widely used Philips PM5544 test pattern. The content and layout of the pattern, as well as the generator, ...
*
Telefunken FuBK The Telefunken FuBK (from the German ''Funkbetriebskommission'' for "''Television Service Commission"'') is an electronic analogue television test card developed by AEG-Telefunken and Bosch Fernseh in West Germany as the successor to the monochr ...


References

{{Standard test item Test cards Broadcast engineering