ETP-1
ETP-1 (or Electronic Test Pattern One)[1] was a test card designed and used by the Independent Broadcasting Authority (IBA).[2][3][4] After test transmissions[5] from the IBA's Engineering Regional Operations Centre (ROC) in Croydon from 1978 it was phased in on ITV over a period starting from 1979,[6] replacing, in different ITV regions: Test Card F,[7] Test Card G and full screen height EBU colour bars.[8][9] After ITV went 24 hours in 1988, the card ceased to be seen on the channel. It was used for both 625-line PAL and 405-line monochrome broadcasts.
It was also seen extensively on both Channel 4 and S4C during both their pre-launch tests and their downtime of those channels, due to their limited hours early on. After launch, it was alternated with in-vision teletext services[7] from ORACLE and 4-Tel on View/Sbectel. On these channels, it was captioned either IBA:CH4 or IBA:S4C,[10][11] with lines above and below this indicating the card was being generated by the channel, the absence of these lines meant it was generated at the transmitter.
After the splitting up of the IBA in 1990, the captioning was changed to NTL:CH4/NTL:S4C.[12] ETP-1 was last broadcast on 31 December 1992 after which Channel 4 showed 4-Tel on View during closedown periods as the channel gradually increased its late night programming, eventually going 24 hours a day early in 1997. After the conclusion of its late-night teleshopping block,[13] S4C shows a closedown slide promoting its S4C Clic VOD service with library music playing in the background during off-air hours.[14]
On 18 April 2012, ETP-1 made one final appearance on Channel 4 to announce the loss of analogue television services in the London region. The card was shown from the Crystal Palace transmitter only, and was the last thing broadcast by analogue Channel 4 before the signal was switched off.[15]
Operation
The test card was generated electronically by a video generator, and includes features for various adjustments and checks:[9][4][1]
- Crosshatch pattern - For CRT color convergence check
- EBU colour bars - Six colour bars at 75% amplitude and 100% saturation for colour adjustments
- Greyscale bar - Six bars at 0%, 20%, 40%, 60%, 80% and 100% amplitude. Allows checking of brightness linearity.
- Multiburst - Six bars of sine wave frequency gratings for bandwidth/resolution check (625 lines: 1.5, 2.5, 3.5, 4.0, 4.5, 5.25 MHz ; 405-line: 1.0, 1.6, 2.25, 2.6, 2.9, 3.4 MHz ).
- 150 kHz square waves - Transient response check, placed above the colour bars.
- Black rectangle within white rectangle - For low frequency response check.
- White needle pulse - Signal reflections check.
- Yellow-red-yellow rectangles - Chrominance/luminance delay check.
- Line synchronisation castellations - Pattern of rectangles in black and colours.
- Colour receiver reference oscillator castellations - Correct color decoding check (Top: cyan, Bottom: green, Left: red, blue, Right: yellow).
- Picture centering castellations - some overscan is normal, but castellations should be visible along all sides of the picture.
See also
References
- ^ a b "Radio & Electronics World, August 1982, p.99" (PDF). worldradiohistory.com.
- ^ Trundle, Eugene (January 13, 1987). Television and Video Engineer's Pocket Book. CRC Press LLC. ISBN 9780434901975 – via Google Books.
- ^ "EBU Review. A, Technical". Technical Centre of the European Broadcasting Union. January 28, 1980 – via Google Books.
- ^ a b "Television-Servicing, June 1982" (PDF). worldradiohistory.com.
- ^ "Test Card ETP1 IBA CH4 without lines". November 11, 2015 – via Flickr.
- ^ "ITA / IBA Tuning Signals". www.meldrum.co.uk.
- ^ a b "IBA Engineering Announcements - 22 October 1985 'The Test Card'" – via www.youtube.com.
- ^ Engineers, Society of Motion Picture and Television (January 28, 1978). "SMPTE Journal: Publication of the Society of Motion Picture and Television Engineers". The Society – via Google Books.
- ^ a b "Not just a pretty face..." March 4, 2016. Archived from the original on 2016-03-04.
- ^ "Test Card ETP1 IBA S4C". October 9, 2021 – via Flickr.
- ^ "Probably The Ugliest Test Card In The World, Dave Jeffery". www2.kecskebak.co.uk.
- ^ "Test Card ETP1 NTL CH4". November 11, 2015 – via Flickr.
- ^ "Press | S4C".
- ^ "S4C End of Teleshopping & Closedown Slide - Wednesday 1st December 2021". YouTube.
- ^ "U.K Crystal Palace Analogue Switch Off 2012 Forever" – via www.youtube.com.