Its not the brain that is slow.  It is retinal persistence that causes
images to merge.  I recently made a light listner converting light to
sound.  The ear can hear 50Hz mains hum for example and much above.  I have
a 50Hz monitor and it flickers if I do not directly view it.  Does the
retina respond slower in the center?


Tim

At 15:41 10/02/97 +0800, you wrote:
>At 07:34 AM 10/02/97 +0000, you wrote:
>>Hi
>>The television uses a refresh of 25 frames per second.  Does your tv
flicker?
>>
>>Tim
>
>All TV's flicker.
>
>Some people notice this flicker - others do not. Depends on a whole range of
>factors. I believe every persons brain has a built in clock rate of around
>20 to 40 cycles per second. There is a basic minimum response time which
>is considered to be a certain multiple of the human clock rate. Thats one
>reason that sprinters (in the olympics) are considered to have a false
>start if there response rate is less than 75mS AFTER the gun !
>
>There seems to be some correlation between metabolic rate and a persons
>likelihood to notice flicker. My girlfriend was diagnosed with a thyroid
>condition that has kept her metabolic rate slow for years - since she
>has been on medication she notices flicker on some SVGA monitors where she
>would'nt notice it before...
>
>Personally I can't stand anything below about 60Hz on a SVGA but put up with
>a TV at 25 since its a smallish screen and the intensity is downand I think
>the phosphor persistence is a bit longer ?
>
>Rgds
>
>Mike
>


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