Before discussing what a plasma display 600Hz sub-field drive is it’s necessary to point out that it is not the same thing as the 120Hz and 240Hz frame rates mentioned in LCD HDTV advertising literature. While the 120Hz and 240Hz are a direct measure of the frame rate per second the 600Hz figure for sub-field drives is not.

Unlike LCD displays which have backlighting, plasma display pixels generate their own illumination within a box like cell structure. Because they can only maintain illumination for milliseconds pixels/cells have to be pulsed rapidly to maintain the illusion of continuous illumination. The advantage high speed sub-field drives is higher pulse rate which can be achieved while maintaining panel/picture brightness. For a 600Hz sub-field drive (Panasonic and Samsung) pixels are pulsed 10 times while each frame is shown. As the frame rate is 60Hz (frames per second) there are 600 pulses per second which is a frequency of 600Hz.
The higher pulsing frequency achieved by 600Hz sub-field drives produces a sharper images, especially for fast on-screen motion) than previous, slower (480Hz) sub-field drives. Plasma HDTVs have a significant advantage in the sharpness with which fast on-screen motion can be rendered.

Full 1080 Lines of Motion Resolution

Marketing for 600Hz sub-field drive plasma HDTVs refers to their ability to display a full 1080 lines of resolution. This statement is inferring that, unlike other (LCD), displays 600Hz sub-field drive plasma display can clearly display 1080 lines of motion resolution. Displaying 1080 lines of static resolution is a far easier achievement than clearly displaying 1080 lines of motion resolution (resolution while displaying on-screen motion). Below is a graphic showing the effect of on-screen motion on resolution.

Motion resolution is not mentioned in marketing documents and it is a point of contention that a test developed to measure it, the http://www.advanced-pdp.jp/news/e_01.html Moving Picture Resolution Measurement System (APDC method), was developed by the Advanced PDP Development Center Corporation which is funded by two plasma HDTV manufacturers, Hitachi and Panasonic. A Hi-Definition Reference Disc by Qtec containing the text pattern for motion resolution testing (and much more ) is available.

Despite the contention about the measurement of motion resolution it is well established that plasma displays handle on-screen motion far better than LCD displays.