In televisions what does 50 hertz mean compared to 100 hertz and does this make a big difference when your going to buy it

[WesterServer]

I am just compering TVs and some have 50 hertz and some 100 hertz, what basically does this do.
Probably alot of people would not even think about this when buying a TV.

But does this make the TV any better when your watching it...

[rojash]

It doesn't make any odds on an LCD TV. With a CRT display, and an analogue signal, the picture used to be refreshed in real time as the signal arrived and was processed. The PAL system used 25 frames per second, but in fact delivered half a frame at a time (interlacing), so each half frame took 1/50 of a second to be displayed (50Hz). The electron beam would excite the dots on the screen, and as soon as it had passed, the dots would start to fade, so the screen would be flickering at 50 Hz. By storing the frames as they arrived, it was possible to double the rate at which the screen was scanned (essentially it just meant refreshing the screen with exactly the same information). The faster the flickering, the less visible it is to the eye, so this had two effects: less apparent flicker, and brighter picture.

The pixels on an LCD only change when "told to" so there is no fading between scans, consequently the only reason for refreshing the screen is to show changes in the frame. Therefore the refresh rate only needs to be as fast as the frame rate (or double the frame rate for an interlaced signal. For analogue PAL that means 50 Hz, and for HDTV, it's usually (I think) 24 or 25 fps.

[WesterServer]

Thankyou so much for that answer, very interesting.
I have just orderd a LCD TV and the specifications say 50HZ and i was a bit curious about LCDs with 100HZ.

So while i am here, this HDTV which is FULL HD 1080p is there much of a difference between an ordinary HDTV and a FULL HDTV.

I was told if you have skyHD your better of going for the fullHDTV, but i am also curious if there is any difference in this or noticable difference