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Old 09-06-2014, 03:20 AM
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ppppenguin ppppenguin is offline
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I hope we can take it as true that with reasonably modern broadcast kit and reasonable engineering standards both PAL and NTSC will give good results.

There are artefacts with both systems. Some relate to the udnerlying scan rates, others, such as lurid patterns on fine detail, are a side effect of the NTSC and PAL systems. These cross colour and cross luminance effects can be minimised by comb filter decoders which were much simpler on NTSC than PAL. Hence they were much more common in NTSC TVs. NTSC has lower chroma bandwidth so transitions between highly saturated colours are a little worse in NTSC. Readily seen on the green/magenta transition on colour bars.

PAL and NTSC have different dot crawl effects. These are primarily visible on monochrome sets. Since PAL subcarrier is a higher frequency they are probably less visible in PAL.

Phase errors should be minimal with decent kit and reasonable engineering.

Now wind the clock back to the early 1960s o even to the 1950s. It is obvious from the work at Hazeltine labs, Telefunken and others that colour phase problems were of great concern. NTSC broadcast kit needed a lot of engineering attention to give consistent colour and the TVs weren't much better. You needed a hue control which can readily be misadjusted by viewers. The idea of colour phase alternation as a solution to this was first raised at Hazeltine labs (c1955?) but was judged impractical then. CPA could be done on dot, line or field basis. The latter 2 were totally out of reach back then. Bruch picked up the CPA idea, did on a line by line basis and invented PAL.

At the time (late 1950s to mid 1960s) BBC engineers wanted to use NTSC and tried both 405and 625 NTSC systems. They reckoned they could wok to high enough standards to keep phase errors acecptable. Aided of course by much more modern kit than was available in the US in 1954. At the same time the french were pushing SECAM as a solution. Totally hideous in the studio and not really capable of being improved by better comb filters and suchlike. PAL was seen as the best answer AT THE TIME. Looking back, 625 NTSC would likely have worked perfectly well.

Hindsight is gloriously 20:20 vision. In the US the coming of NTSC brought the decision to offset the line and frame rates by a harmless fraction of a percent. To avoid moving the sound subcarrier by a similar amount. Who was to know back then the sheer amount of grief that would cause for broadcasters when timecode was invented. Grief that continues to this day as all the 1080 and 720 systems have widely used options for 59.94Hz and other field rates with a 1000/1001 offset.

The whole PAL/NTSC debate is now well behind us. For some years nobody (I'm sure somebody will find me an example of a small station in Africa that still uses PAL) has been producing new material in a composite format. High quality decoders are available to decode PAL and NTSC to their components with excellent results. Almost nobody is even radiating PAL or NTSC now.
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