@barrister
Sir, if you can read this I have a question for you sana, The Sammy A650 uses a so-called 120Hz LCD technology and how does that compare to the 480hz "sub field" drive ng Panny Py800? Are they the same?
No, they're definitely not the same. A 120 Hz LCD displays 120 fps (frames per second). But a 480 Hz plasma displays only 60 fps.
I'm pro-plasma, but this time I have to admit that LCD has the true spec, while plasma has a marketing gimmick.
The objective of a higher frame rate or frequency is to reduce the judder caused by the conversion of film (with 24 fps) to video (with 30 fps or 60i [NTSC] and 25 fps or 50i [PAL]).
Judder is reduced by motion interpolation, a techniqe that repeats the video frames to produce 120 fps for NTSC and 100 fps for PAL. Hence, the specs "120 Hz" and "100 Hz". Motion will be smoother, but the side-effect is an unnatural look, similar to a home video shot on a Handycam. Despite the unnatural look, many customers seem to like it.
AFAIK, plasma's highest frame rate frequency is presently only 72 Hz (by Pioneer). Nevertheless, plasma has no choice but to come up with their own high frequency spec or risk losing sales to LCD.
To compete with LCD specs, plasma divides the frame into sub-fields. If they divide the frame into 8 sub-fields, then 60Hz (frames per second) x 8 sub-fields per frame = 480 sub-fields per second; and 50Hz x 8 sub-fields = 400 sub-fields per second.
But the frame rate would still be 60Hz and 50Hz.
Similarly, Pioneer plasma can claim an 840Hz spec (14 sub-fields x 60Hz), but frame rate would still be 60Hz.
Plasma pixels are either on or off. To produce an accurate gray scale, the intensity of each pixel is varied by flickering. That's where a sub-field comes in --- it's the length of time within a frame period that a pixel emits light. If there are 8 possible sub-fields per frame, those 8 sub-fields can be used in different combinations to form the required gray scale.
Surprisingly, plasma's 480 Hz spec actually has nothing to do with judder and motion interpolation. Let's just say that it's a spec that came from the marketing department rather than the engineering department.