Talk:Philips circle pattern

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using the correct or best image

when i found this page it was showing a rather ugly hand drawn version of the PM5544 so i uploaded and used my own version. it is also drawn, but it is very accurate due to following the technical specification of the PM5544 as close as possible. then someone called RTFMASAP comes and reverts it *and* changes the correct, screencapped, PM5644 (widescreen) with another drawn, and wrong, one.

some examples of differences:

- the color bars and yellow at the bottom are really 75%, not 100%. this is because (modulated) composite video cannot show fully saturated colors at 100% brightness. this is also used for "blue only" mode, where they have the same brightness as the grey block pattern right above it.

- the resolution pattern below the centre is a sine wave pattern, not a square wave pattern, hence it looks blurry.

- the colors in the [ ] aren't chosen at random, they are special YUV colors and can be accurately calculated.

- the horizontal grid lines are all 2 scanlines thick. the horizontal convergence test line in the center is also 2 scanlines thick, and at an odd number of scanlines difference from the grid lines to allow for an interlaced line pairing test.Bewareircd (talk) 17:42, 13 July 2008 (UTC)[reply]

- the grid squares are 42 scanlines high.

- also, PM5644, widescreen, is *not* HDTV. it is standard definition PAL, but simply stretched out to 16:9 aspect ratio. —Preceding unsigned comment added by Bewareircd (talk • contribs) 22:26, 12 July 2008 (UTC)[reply]

the other testcard: [1]

my testcard: [2]

reference page: [3] you can read the full specs, and also make visual comparisons between my and the other test card here, and the numerous test card pictures on that page - scroll down on it. Bewareircd (talk) 22:14, 12 July 2008 (UTC)[reply]

Equipment vs. Test Pattern

The article doesn't make a clear distinction between the PM5544 test pattern generator (the equipment) and the PM5544 test card (the output signal) that it generates. In the opening sentence the PM5544 is described as a "test pattern generator", later the article talks about "this test pattern", and later again about "the unit", suggesting equipment again. I believe this should be solved. Note that the Philips PM5544 is not the only equipment used to generate PM5544 test patterns. Jaho 07:06, 1 December 2007 (UTC)[reply]

By the way, does someone have a picture of an original Philips PM5544 unit (the equipment)? Jaho 07:12, 1 December 2007 (UTC)[reply]

I have rewritten the article somewhat to emphasize the differences between the original PM5544 generator, and the test card produced (Philips Pattern). The article still needs some polish and references, and I'll try to amend it as I find good resources. Zacabeb (talk) 20:16, 22 May 2009 (UTC)[reply]

PM5544 test pattern technical questions

Which tests and checks can be done with this test card? Abdull 13:27, 17 April 2006 (UTC)[reply]

An answer to your question can be found here: [4]. Jaho 03:26, 1 December 2007 (UTC)[reply]

Don't know how much this explains, but in the Swedish version, there was a small line moving, and the correct time was given digitally. 惑乱分からん 19:12, 28 September 2006 (UTC)[reply]

Apparently you're talking about the animated digital version. Info about that moving line can be found on the same article as above (here: [5]; scroll down a bit). Jaho 06:25, 1 December 2007 (UTC)[reply]

Test Pattern used in Australia

This Test Pattern was also used by ABC Television Australia. Kathleen.wright5 11:30, 15 September 2007 (UTC)[reply]

Actually a huge number of broadcasters around the world are using this test pattern in some form, I believe it wouldn't be a good idea to mention them all here on wikipedia. I've removed your remark from the article. Jaho 03:18, 1 December 2007 (UTC)[reply]

SABC in South Africa

SABC in South Africa used a variation of the Philips PM5544 Test Card in the 1980s. -- Firefishy (talk) 10:33, 3 March 2009 (UTC)[reply]

Better version of the 16x9 (PM5644) test pattern added

The existing screen captured version was small and very jagged, so I uploaded a full resolution version I have created in graphics software to match specifications as closely as possible. It reveals the small circles with definition lines, as well as the non-switched carriers in the outermost columns which were used in analog broadcasts to reveal phase errors in the color decoding.

Zacabeb (talk) 22:27, 13 May 2009 (UTC)[reply]

reversed image to previous version

I've replaced the newly (dd. 30 aug 2009) linked svg image by the old png version, because the new image contains several issues:

Colour bars 100% and not 75%.
Block pattern in stead of sine waves.
Lines in centre too thin and inaccurate.
Circle not in the middle (or background displaced?).
More issues, but I didn't investigate further.

An svg image is of course preferred over a png, but this isn't anywhere near the specs. The old png image is pixel accurate, as far as I can tell. Jaho (talk) 07:18, 8 September 2009 (UTC)[reply]

File:Philips PM5544.svgI repair some bugs.Tucvbif (talk) 20:47, 9 September 2009 (UTC)[reply]

does the image even *need* to be a svg? the original image is discrete in the vertical axis (it is made of scanlines), it is arguably continuous on the horizontal axis because it's analog video. i'd only prefer the SVG if it can, atleast, obtain pixel precision (for example, sine wave pattern is really a sine wave, and so on)Bewareircd (talk) 16:11, 12 November 2009 (UTC)[reply]

i've looked at the "bug fixed" SVG, as of now, it still has lots of problems. such as:

grid size seems to be 43, should be 42 pixels
the horizontal lines are 3 pixels high, should be 2 pixels
the vertical lines are, however, wider than 2 pixels (their real width is defined in the time domain)
the frequency patterns are triangle patterns, should be sine patterns. also the frequencies seem to be inaccurate.
the rightmost two squares of the bandwidth patterns are not precisely squares - the rightmost is less wide. in reality they're squares.
colors change on grid lines, and the white lines are *centered* on the grid lines. this is done wrong (see the [ ] pattern)
the 250 kHz pattern looks inaccurate. it's dark parts are wider than it's light parts. also in reality it does not neatly align on pixels (if you display it as pixels)

Bewareircd (talk) 16:34, 12 November 2009 (UTC)[reply]