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 by engineer Finn Hendil (; 1939–2011) in the Philips TV laboratory in Copenhagen under supervision of chief engineer Erik Helmer Nielsen in 1966–67. The equipment, the PM5544 Test Pattern Generator, which generates the pattern, was made by engineer Finn Hendil and his group in 1968–69. The same team would also develop the Spanish TVE colour test card in  1973. Since the introduction of the PM5544 in the early 1970s, the Philips Pattern has become one of the most commonly used test cards, with only the SMPTE bars and the BBC's Test Card F coming close to its usage. The Philips PM5544 pattern was later incorporated into other test pattern generators from Philips itself, as well as test pattern generators from various other manufacturers. Various configurations and modifications exist. Other related test card generators and patterns by Philips are the PM5400 family (with support for widescreen and PALplus), PM5515/16/18, PM5519, PM5520 (monochrome), PM5522 (PAL), PM5534, PM5538 (see section  below), PM5540 (monochrome), PM5543, PM5547, PM5552, PM5643, PM5644 (widescreen, see section below) and PM5572/73/74. Operation. Rather than previous test card approaches that worked by a camera or monoscope filming a printed card, the Philips PM5544 generates the test patterns fully using electronic circuits, with separate paths for Y, R-Y and B-Y colour components (Y′UV), 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. Displayed  image geometry (image centering, correct proportions of the circle, etc.) can also be corrected. More technical adjustments are also possible. Main technical features of the test card: Variations. While the basic specifications of PM5544 normally remain consistent, there are often small variations to the Philips Pattern depending on the brand and type of generator used to produce it, as well as how the broadcaster has chosen to configure it. NTSC and SECAM. The Philips PM5544 pattern is geared towards the PAL colour-coding system, but NTSC and SECAM versions exist. The most obvious difference is the absence of PAL specific  test features (to two normally invisible outmost vertical bars). The 512-lines NTSC versions use different spatial frequencies. One of the NTSC variants, used in Philippines, Taiwan and Japan (multiburst portion slightly modified for NTSC-J), has the checkerboard pattern near the top of the circle at 300 kHz and the multiburst gratings at 0.5, 1.0, 2.0, 3.0 and 4.0 MHz. A second variation, used by CBC Montreal in Canada, had different gratings and added extra colour bars. PM5644 (widescreen). A widescreen-capable Philips Pattern generator, the PM5644 PALplus test pattern generator, was introduced by Philips in the 1990s and  featured support for the emerging PALplus widescreen standard. This version of the test card retains the signals present in the original, and features additional signals to test signal and picture quality, including Television lines resolution and correct overscan and image centering. As with PM5544, the widescreen Philips Pattern was adopted by various other manufacturers of test pattern generators (ex: Fluke PM5420). It was used by broadcasters such as RAI (Italy), BRT (Belgium), RTL-TVI (Belgium/Luxembourg), Ned3 (Netherlands), TVE (Spain), 2RN (Ireland) and El Trece (Argentina). PM5538. A squared version of the Philips PM5544 test pattern, called PM5538, was used  by some stations in some parts of the Middle East like Dubai 33 and Jordan Radio and Television Corporation (JRTV) in Jordan. GB2097 inspection chart. China Central Television used a heavily modified version of the PM5544 called the GB2097 inspection chart. Wordwide usage. PAL broadcasts. Many broadcasters using a 625-line PAL system used some form of the Philips PM5544 pattern. The BBC occasionally used a slightly modified version called Test Card G from 1971 until the late-1990s, in conjunction with Test Card F. The Independent Broadcasting Authority (IBA) initially used this card in the 1970s, also in conjunction with  Test Card F, but eventually abandoned Test Card G and developed a unique test card called the ETP-1, which was brought into use on ITV from 1979 onwards. However, London Weekend Television (LWT) and ITV Channel Television, two constituent franchisee companies in the ITV network structure, continued to use Test Card G well into the 1980s and 1990s. The PM5544 was also used by Raidió Teilifís Éireann (RTÉ) in the Republic of Ireland (in conjunction with the EBU colour bars shown after the Irish national anthem was played at closedown) from the start of its regular colour broadcasts in 1972 . The PM5544 was also in widespread use in Australia for many years, most notably with the Australian Broadcasting Corporation (ABC) from its launch of colour broadcasts in 1974–75 and Special Broadcasting Service (SBS) from its launch of television services in 1980. Some commercial stations also used it. In New Zealand, it was used by TVNZ from its launch of colour broadcasting in 1973. In Southeast Asia, the PM5544 test card was first introduced by Radio Television Singapore (RTS; now Mediacorp) (in conjunction with a modified version of Test Card F) upon the start of regular colour broadcasts in Singapore in  1974. The PM5544 was later introduced in Malaysia by its public broadcaster Radio Televisyen Malaysia (RTM) during its introduction of regular colour broadcasts in 1978–1980, replacing the monochrome Pye Test Card G, and was also used by said country's first commercial station TV3 from the launch of its television service in 1984 until it switched to a 24/7 schedule in 2014. The PM5544 was also used by the Indonesian national TV broadcaster TVRI from its launch of colour broadcasts in 1979–1982 until it switched to a 24/7 schedule in 2021. In Hong Kong, the PM5544 was used by RTV /ATV and TVB from the 1970s (replacing the RMA 1946 Resolution Chart and EIA 1956 resolution chart) until approximately 2007–2009. TVB then switched to its own test card designs incorporating elements of the PM5544, PM5644 and Snell & Wilcox SW2 designs. In the People's Republic of China, the PM5544 was used by its national broadcaster CCTV as well as some provincial/regional broadcasters such as Shenzhen Media Group and Television Southern in Guangdong Province, Xizang STV in Tibet Autonomous Region, Yuyao TV in Zhejiang Province and Ningxia Television in Ningxia Hui Autonomous Region. CCTV also later used a heavily modified  version of the PM5544 called the GB2097 inspection chart. Nowadays, many modern Mainland Chinese test card designs, like in Hong Kong, incorporate elements of the PM5544, PM5644 and Snell & Wilcox test card designs. In the DACH countries, the PM5544 test card was used by the German commercial terrestrial channel RTL and the German public-service channel Phoenix. The Austrian public broadcaster ORF used a slightly modified version of the PM5544. Use of the PM5544 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 Italy, its national broadcaster RAI introduced the PM5544 test card in 1977 at the same time as it launched its first regular colour broadcasts, replacing heavily modified versions of the Indian-head test pattern. Later on, RAI then used the PM5644 widescreen variation for PALplus broadcasts. Telefriuli also used a heavily modified version of the PM5544 in the 1980s. In Spain, the PM5544 was introduced by the various autonomous and private channels in the early-1980s notably by TV3, El 33, Telemadrid, Antena 3, and Canal+ Spain, as well as on point-to-point terrestrial and  satellite links operated by Retevisión and Telefónica Sistemas de Satélites. Spain's national public broadcaster TVE however instead used its own TVE test card card from 1975 until the mid-2000s. In South Africa, the South African Broadcasting Corporation (SABC) made use of the PM5544 pattern since they started testing their first television system in 1975, but independent broadcasters M-Net, which launched in 1986, and e.tv, which launched in 1998, opted to use Telefunken FuBK instead. In Argentina, the PM5544 was used by América TV and El Nueve. in Niger PM5544 was used by Télé Sahel In Israel, the PM5544  was used by Israel Broadcasting Authority (IBA) 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 the former SFR Yugoslavia, the PM5544 was used by its national broadcaster Yugoslav Radio Television (JRT) in conjunction with the Telefunken FuBK test card. Use of the PM5544 continued for some time afterwards in some of its constituent successor countries. In Qatar the testcard was used by Qatar TV. The PM5544 was also  used in Algeria, Kuwait, Hungary, Belgium, Netherlands, Denmark, Norway, and Sweden. Saudi Broadcasting Authority (SBA) in Saudi Arabia used a heavily modified version of the Philips PM5544 pattern from 1982 until 2009, with the side "brackets" removed and 1/4 of the top half of the PM5544 "circle" replaced with a white and black background and colour bars. Some television stations have also been seen to have included a digital clock and/or date, as well as the station logo or ID, inside the "circle" of the PM5544 test card. This practice is common in Asia and in some parts of Europe , as well as in South Africa. SECAM and NTSC broadcasts. Since the Philips PM5544 pattern is geared towards the PAL colour-coding system, this test pattern is uncommon, though still used among NTSC and SECAM broadcasters. NTSC users of the Philips PM5544 test card included CBFT and CBMT in Quebec, Canada, WBOY-TV and WNYW in the United States, DZBB-TV in the Philippines, Myawaddy TV in Myanmar, KBS and MBC in South Korea and TTV Main Channel, CTV Main Channel and CTS Main Channel in Taiwan and RTNH in Haiti. The Japanese national broadcaster, NHK, also used a 525 -line version of the test card, albeit with slight technical differences as compared to those used by the American and Canadian broadcasters so as to conform with the NTSC-J system. SECAM users of the Philips PM5544 test card included TDF (TF1, Antenne 2, FR3, Canal+, La Cinquième and M6) in France, Iraqi TV in Iraq, VTV in Vietnam, bTV in Bulgaria and SNRT in Morocco. TVP in Poland started using the PM5544 for SECAM transmissions since the 1970s and continued using it after switching to PAL in the 1990s.