Refresh rate question

[adge666]

Hi I'm new around here, I hope you can help, this is for my dissertation.

If I send a timed image to a (common or garden Dell or laptop) 60Hz LCD monitor, of say 15ms, will it display for the full screen refresh of 17ms? What would happen if I send a 25ms timed image? Will it display for 2 x 17ms = 34ms? I also read somewhere that even if I send a 17ms image, it may be displayed up to 1.5 screen refreshes.

What I really need to know how long a 25ms image is likely to remain on the screen. Hope you can help! I'm writing about subliminal exposures by the way.

Thanks Adge

 

[Schmide]

Making this up as I go along.

viewed refresh rate = actual refresh rate * ( (desired refresh rate / actual refresh rate) + ( 1 if (desired refresh rate modulus actual refresh rate) > 0))

or

vrr = arr * ( (int) ( drr / arr)) + ( drr % arr ? 1 : 0) )

for 25ms on a 17ms monitor

17 * (( (int) ( 25 / 17 )) + ( 25 % 17 ? 1 : 0) )
17 * ( 1 + 1)
34ms

You really need to watch the vertical blanking to perform discrete updates like you desire, but I think what you are desiring is. If you update the image between refreshes, it will only display after the next refresh.

There is no such thing as a 1.5 screen refresh, if you miss the last refresh the visual update will happen during the next refresh. This is why PAL sucks.