Philips circle pattern

The content and layout of the original colour circle pattern was designed by Danish engineer Finn Hendil [da] (1939–2011)[1] in the Philips TV & Test Equipment laboratory in Amager (moved to Brøndby Municipality in 1989) near Copenhagen under supervision of chief engineer Erik Helmer Nielsen in 1966–67, largely building on their previous work with the monochrome PM5540 pattern.

), allowing engineers to reliably test and adjust transmitters and receivers for signal disturbances and colour separation, for instance for PAL broadcasts.

In simple terms, the displayed pattern provides reference levels of black, white and colour saturation, to which a receiver can be set.

Main technical features of the test card: While the basic specifications of the pattern normally remain consistent, there are often small variations depending on the brand and type of generator used to produce it, as well as how the broadcaster has chosen to configure it.

Although no public transmissions are known to exist as of February 2025, the pattern is identical to NTSC but also includes achromatic fields adjacent to the side bars.

The original 1991 pattern contains high frequency components which were useful for testing widescreen televisions in factories, specifically 450/400 TVL diagonal lines and a sixth 5.8 MHz grating.

Widescreen circle patterns were used by broadcasters such as RAI (Italy),[20] BRT (Belgium),[21][20][22] RTL-TVI (Belgium/Luxembourg),[23] Ned3 (Netherlands),[24] TVE (Spain) and KNR TV (Greenland).

[32] Starting from the 1980s, China Central Television and some provincial mainland Chinese broadcasters began using a heavily modified version of the PM5544 called the GB2097 inspection chart.

[33][34][35][36][37][38] Later, another modification, anecdotally called PM5549 (the Philips PM5549 was an unrelated product)[39] began to be used at the headends of some mainland Chinese cable television providers.

The last known design has controls and a display on the front panel and is labelled PM5644 PALplus test pattern generator and bears the model number PM5644/85.

This design also generates the well known 16:9 colour circle pattern but unlike the previously mentioned G/90 and G/924 models, it is capable of encoding a PALplus signal.

Appearance of text is significantly different to the PM5644 and from experimentation with physical equipment it is considered likely to be responsible for at least one public transmission (from Nederland 3 in the Netherlands), which was able to be exactly recreated.

[59][60] Around this time Philips exited the TV test equipment business, with the lab that developed these products independently incorporated as ProTeleVision Technologies A/S.

Other pattern generator products not included in the sale, but still under warranty or with active support plans such as the PM5644 and PM5534 were abandoned by ProTeleVision to be fulfilled by Arepa Test & Calibration.

[72] Due to hardware limitations, it was not possible to enable both text in the bottom box and a moving bar with the sole exception of a workaround developed for SVT.

The Philips circle pattern was later introduced in Malaysia by its public broadcaster Radio Televisyen Malaysia (RTM)[96][97] from its introduction of regular colour broadcasts in 1978–80 (replacing its previous monochrome Pye Test Card G) until it switched to a 24/7 schedule in 2012;[citation needed] and was also used by said country's first commercial station TV3 from the launch of its television service in 1984 until it adopted a 24/7 schedule in 2014.

[98] The Philips circle pattern was also used by the Indonesian national TV broadcaster TVRI, replacing its previous Telefunken FuBK test card,[99] from the mid-1980s until it switched to a 24/7 schedule in 2021.

In the People's Republic of China, the Philips circle pattern was used by its national broadcaster CCTV[111] as well as some provincial/regional broadcasters such as Shenzhen Media Group[citation needed] and Television Southern[112] in Guangdong Province, Xizang STV[113] in Tibet Autonomous Region, Yuyao TV in Zhejiang Province and Ningxia Television[114] in Ningxia Hui Autonomous Region.

In Israel, the Philips circle pattern was used by Israel Broadcasting Authority (IBA)[120] and Israeli Educational Television (IETV) from their launch of colour broadcasts in the early-1980s, replacing its previous monochrome Philips PM5540 test card after a nearly decade-long delay in introducing colour television to said country for various sociopolitical reasons.

In Greenland, the standard and widescreen Philips circle pattern are used by its public broadcaster Kalaallit Nunaata Radioa (KNR) from its launch of television services in 1982.

[25] A modified variant of the widescreen Philips circle pattern is used by the Faroese public broadcaster Kringvarp Føroya (KvF) alongside the EBU colour bars during off-air hours.

Nozema [nl], the operator of all national radio and television broadcasting infrastructure in the Netherlands, also used the Philips circle pattern.

However, Ziggo, the largest cable television provider in the Netherlands, still offers the widescreen Philips circle pattern on channel 997.

[147] The Philips circle pattern was also used by Raidió Teilifís Éireann (RTÉ)[148] in the Republic of Ireland (in conjunction with a modified version of the EBU colour bars shown after the Irish national anthem was played at closedown) from the start of its regular colour broadcasts in 1972 until they were replaced by RTÉ Aertel overnight in-vision teletext in mid-1996.

[153] Use of the Philips circle pattern in the DACH was solely confined to these broadcasters, as most TV stations in these areas instead preferred to use the Telefunken FuBK test card when they adopted colour television.

In the former SFR Yugoslavia, the Philips circle pattern was used by its national broadcaster Yugoslav Radio Television (JRT)[159] in conjunction with the Telefunken FuBK test card.

In Bulgaria, the privately owned nationwide broadcaster bTV[160] introduced the Philips circle pattern in November 2000 with the start of its new program schedules, replacing the EBU colour bars, used from its launch on 1 June 2000.

Use of the Philips circle pattern was in its test card broadcasts until 17 February 2001 between 12:00 AM and 06:00 AM (the next day, bTV started 24-hour transmissions), and 2 times a year during transmitter maintenance until 2013.

SECAM users of the Philips circle pattern included TDF (TF1, Antenne 2, FR3,[169] Canal+,[170] La Cinquième and M6[171]) in France, Télé Sahel in Niger,[172] Iraqi TV[173] in Iraq, VTV[174][175] in Vietnam and SNRT[citation needed] in Morocco.

[178] NTSC users of the Philips circle pattern included CBFT[179] and CBMT[180][181] in Quebec, Canada, WBOY-TV and WNYW[182] in the United States, DZBB-TV in the Philippines, Myawaddy TV in Myanmar, KBS and MBC[183] in South Korea, TTV,[184] CTV,[185] CTS[186] and FTV[187] in Taiwan and RTNH in Haiti.