Multisystem TVs and different vertical resolutions

[hadiceberg]

Hi
as you know, NTSC uses 486 visible lines and PAL has 576, therefor these two have different vertical resolutions.

I wonder how TVs can display both on the same CRT?

Does their CRT actually have higher vertical resolution? (as in CRT PC monitors that have much higher resolution than used which enables them to support multiple resolutions - unlike LCDs)

[jagabo]

The TV simply sprays a beam of electrons onto the phosphors on the front of the CRT. The size (pitch) of the phosphors is small enough that it can accommodate the required resolutions.

Sony Trinitron tubes have phosphors in vertical stripes so they can accommodate any vertical resolution. http://www.meko.co.uk/aperturegrille.shtml

[edDV]

..Does their CRT actually have higher vertical resolution? (as in CRT PC monitors that have much higher resolution than used which enables them to support multiple resolutions - unlike LCDs)[/size]

The phosphor density (dot pitch) varies TV to TV. Since a CRT TV scans behind the aperture grill or shadow mask a full 480, 486, 576, 720, 1080 lines are scanned but the resolution detail seen from the front is limited by the dot pitch.

Many HD CRT TV sets scan 1080i (540 lines at a time) but actual screen resolution is often less than 800x600.

[hadiceberg]

jagabo, edDV
Thank you for the valuable information.