We’ve had a few emails to GadgetGuy lately regarding disappointing results with the picture quality of some no-name LCD televisions. In industry-speak, they’re what’s known as ‘yum cha’ brands – basically you get in touch with someone in China, choose from a shopping list of panel sizes and resolutions, components and cases, and slap your own badge on it.
Not all of them are bad, some provide decent results for a very modest price. But there are pitfalls.
The one coming to our attention involves the frequency at which the TV natively operates, its associated term of measurement – hertz – and its application in the world’s two major video systems, PAL and NTSC.
Now, to some broad definitions of these terms.
PAL (Phase Alternating Line) is the television coding system used in Australia and Europe, while NTSC (National Television System Committee) is used by much of the rest of the world, with the USA being the biggest member of the NTSC club. Hertz, as applies to TVs, is the frequency with which the video frames – and half frames – that comprise an image are presented to the screen.
The difference between these two technologies, and the focus of this article, is that the NTSC system updates the onscreen image 30 times per second, or at frequency of 60Hz, while PAL updates at 25 times per second, or at 50Hz. In short, NTSC video is made to display optimally on 60Hz screen, and PAL video on a 50Hz screen.
To press the point, you’ll notice that when big companies extol the virtues of ‘hertz’ technology in Australia that it’s always a multiple of fifty -100Hz was once the buzz, now 200Hz is the cutting edge of LCD TV tech. These TVs are optimised for the Australian market and its PAL video system.