how does super-hires work technically on 640 display?

I realize super-hires mode halves the pixel timing to 35ns, but the rgb pixel elements of a tv or 1080/1084 are arranged basically to support 640 pixels across (plus overscan), not 1280, so how exactly does super-hires display work?

Thanks!

[Michael]

Works perfectly on HD displays, they have more pixels. Also classic large CRT screens don't have pixels as such, so a beam can hit the dot twice while scanning the lines (left half and then right half)

Originally Posted by Michael

Works perfectly on HD displays, they have more pixels. Also classic large CRT screens don't have pixels as such, so a beam can hit the dot twice while scanning the lines (left half and then right half)

color tv and analog rgb monitors basically have shadow masks and 3 vertically striped electron-catching "boxes" per pixel, so they do have pixels. are you saying super-hires works by hitting the phosphor at different angles left and right while hires only fires electrons in one direction of the raster?

[demolition]

The dots or stripes in the shadow mask are not syncronized with the screen resolution like the pixels on an LCD, so the electron beam can easily project more pixels than there are holes in the mask, although a high dot pitch (fewer holes) in the mask will lower the effective resolution, causing blurring of the picture. Thus it might not be possible to distinguish individual pixels on a low quality display.

demolition,
yes i know what you mean about the shadowmask, but it has openings onto the dots/stripes in which RGB phosphors are located. so the electron gun "missing" these phosphors would either strike the mask or create bizarre color confusion (like the way subpixel displays can appear awful).

so are these phosphors being hit twice in super-hires? i.e. for example, first, the left half of each RGB phosphor is hit in 35ns then the right half of each RGB phosphor is hit in 35ns?

[demolition]

Some might get hit twice, but there are also gaps between them, so some pixels might not be seen at all. And yes, does create an interference effect, called Moiré.

[pandy71]

shires works same as hires - it is analog, continuing signal - as there is no direct pixel addressing (as in LCD or PDP) devices, if signal is beyond display capabilities it will be blurred (bandwidth limited by series low pass filters i.e. video amplifier, mask, phosphor)

So it will look more or less as "Gaussian" (bandwidth limited) pulse than rectangular pulse i.e. _/¯\_ than _|¯|_ .

But it is important to realize that anyway such information is not totally lost and can be partially recovered.