Talk:Philips circle pattern

Example pictures may go if we don't sort out their licensing, due to possible copyright violation
It seems that anything previously issued as Public Domain is now under scrutiny of Wikimedia Commons and may get deleted unless the uploader verifies they have the right to publish those works. I've sent an inquiry to ProTelevision who owns what's left of Philips' labs in Denmark to check if they can help. So, we need to double check if this test card has ended up in the public domain, or get a license to publish them on Wikipedia.

But be prepared that this might soon become an artcle with text only and no pictures. Zacabeb (talk) 01:12, 3 February 2013 (UTC)

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)

- 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)

the other testcard:

my testcard:

reference page:  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)

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)

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


 * 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)

PM5544 test pattern technical questions
Which tests and checks can be done with this test card? Abdull 13:27, 17 April 2006 (UTC)
 * An answer to your question can be found here: . Jaho 03:26, 1 December 2007 (UTC)

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

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

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)

PM5538 doubts
I have not been able to find any credible materials that confirm that there was any such thing as a PM5538. Everything on the internet references back to this page, which references nothing. Looking at it, it doesn't even make sense. The square is overwriting part of the sidebars. Seems a bit broken and unlikely Philips would offer this officially not least because the circle is such a valuable part of the pattern. It's hard to know why anyone would want to do away with it. What I did find is that both the PM5544 and PM5534 internally generate the central part of the pattern as a square in the exact dimensions seen in the only recording of this pattern I could find (UAE TV), however it is normally cropped to a circle by its "circle generator" module.

Interestingly this is an actual known fault mode in the PM5544 and PM5534. When the circle generator fails, in some cases it can show this exact pattern. Alternatively if it is removed or disconnected from the unit, once again it will output this pattern. I am slightly concerned this page has spread a lot of myth about a non-existent variation which in reality may have been a recording of a 5544/34 which went bad, and perhaps the broadcaster just couldn't be bothered getting it fixed. If anyone knows of anything that can support the current theory of a PM5538 please add a reference! Inaxeon (talk) 16:22, 27 December 2022 (UTC)


 * I think the current version mentioning fault modes and the way they might be mistaken for a pattern variations is a good solution.4throck (talk) 18:26, 30 December 2022 (UTC)

PM5538 & PM5549
There has been a further development regarding the PM5538 (and PM5549). I recently obtained a paper copy of the comprehensive PTV catalogue from 1982. There are some interesting points contained within it (I am yet to scan all of it) regarding this page:

PM5538
This was a product from Philips, however it is not a pattern generator, it is in fact a teletext generator:

Details here: https://xpander.mattmillman.com/files/linked/PM5538.pdf

I suggest that all references to PM5538 be removed, however there is the question of existing folklore originating from this page. Should this be preserved/mentioned in any way?

PM5549
Another product referenced on this page I've been a bit sceptical about but I have left this alone because there are references to it around the internet specifically being a video generator.

Details: https://xpander.mattmillman.com/files/linked/PM5549.pdf

It does not look like something that is going to be generating any Chinese test cards I would say. I think the references to PM5549 also need to be removed. I can't see any other references to anywhere else on the internet.

PM5644 section re-written

 * I have removed the "(widescreen)" text after the title. I'm concerned that this is spreading widespread assumptions that the PM5644 is solely for generating widescreen patterns when this has now been demonstrated not to be the case.
 * PM5420 is noted to use a visually similar pattern to the PM5644 widescreen variation, not the exact pattern. The manual referenced by that assertion clearly shows this.
 * This section is now suffering from a familiar tug-of-war between those who want to talk about equipment and those who want to talk about patterns. Open to suggestions as to how to improve.
 * I notice that elsewhere on the page there are several patterns displayed which are stated to be "PM5544" but actually they look more likely to be generated by a PM5644. The "CTV Main Channel" and "TTV Main Channel" patterns are blatant examples of this but I cannot actually prove it. Just noting it.
 * I'm a bit wary of mentioning the 2RN Ireland testcard in the PM5644 section. As I understand this is still used even today over digital broadcasts. I think it is unlikely that an analogue pattern generator would still be being used in the present day instead more likely this is just a piece of software unless anyone has any specific information on this? — Preceding unsigned comment added by Inaxeon (talk • contribs) 20:26, 1 November 2022 (UTC)


 * Thanks for your improvements. I don't see any problem with discussing hardware or related patterns, they show the evolution of equipment and TV standards. 4throck (talk) 18:16, 1 November 2022 (UTC)

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)

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: 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)
 * 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.

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

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)

i've looked at the "bug fixed" SVG, as of now, it still has lots of problems. such as: Bewareircd (talk) 16:34, 12 November 2009 (UTC)
 * 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)

Finn Hendil died
84.129.190.114 (talk) 23:05, 4 February 2011 (UTC)
 * born 23 February 1939
 * died 30 January 2011
 * "Finn Hendil : Dødsfald" see http://www.navne.dk/8133188
 * Info in Danish on Finn Hendil see http://www.recordere.dk/indhold/templates/design.aspx?articleid=4723&zoneid=5 (3 February 2011)

Regarding rasterized (PNG) vs vectorized (SVG) renditions of the test pattern
On Wikimedia there are renditions of the PM5544 and PM5644 test patterns in both rasterized and vectorized forms.

While in many cases it is preferable to use a vectorized image since it can be scaled to any resolution, in the case of test patterns it depends on how the test pattern functioned. Many traditional test patterns that were originally produced by a monoscope are resolution agnostic and may be rendered in vector form. Electronic test patterns like the PM5544 and PM5644 however, were generated directly around the television raster and have properties that are tied in with that. For instance, the horizontal lines in the grid are two lines tall (one line per field). Maintaining those properties in vector form so that the image is rendered correctly in its native resolution is very difficult.

In addition, there are many signals which cannot be represented correctly in SVG. Sine waves cannot be described easily in SVG since it only supports linear gradients.

This means that the SVG versions found contain a lot of inaccuracies. While some of those issues could be worked around, it would take a lot of effort to ensure that the result still adheres to the original properties and renders correctly at its native resolution.

I think it is important that the examples displayed on Wikipedia are as accurate as possible to the patterns produced by actual generators and not just arbitrary renditions.

Therefore, I consider it preferable to use PNG versions created to closely adhere to the specifications of those test patterns, unless there are SVG versions made that still adhere to the correct properties of the test patterns if rendered at their native resolution.

Zacabeb (talk) 13:46, 9 June 2021 (UTC)