Flat screen monitors and refresh rates (Hz)
- Thread starter SheepCow
- Start date
- Joined
- Dec 22, 2003
- Messages
- 3,351
I believed this was exactly the same as on the CRT's - the refresh rate is the number of times the image is drawn on the display every second. It certainly wouldn't make sense for a very exact term to have it's meaning changed.
I've had a hunt around and even spoke to a friend at CTX UK (chuntex, local folks who manufacture a lot of OEM displays, mostly budget makes like Belinea, CTX and Proview). Apparently the refresh rate certainly isn't the same thing as on the CRT's - as indeed the pixels are in a fixed state until changed otherwise.
I was introduced to some mathematics though : apparently the fastest "refresh rate" you will get out of a TFT is "1000(ms)/response" - my TFT's response time is 8ms, meaning it effectively has a refresh rate of 125hz - although it's only capable of 75hz according to control panel and a few tests
That would mean that the fastest my panel should be able to display a picture is 75 frames per second - (one frame every 13.3ms).
I'm not sure if that's entirely helpful or easy to understand, it has actually confuse me a little too. It could just be me misunderstanding the mathematics or it's just marketing bollocks - people giving "best case scenario" numbers instead of actual.
If theres any more info someone can shed I'm sure it would be useful
I've had a hunt around and even spoke to a friend at CTX UK (chuntex, local folks who manufacture a lot of OEM displays, mostly budget makes like Belinea, CTX and Proview). Apparently the refresh rate certainly isn't the same thing as on the CRT's - as indeed the pixels are in a fixed state until changed otherwise.
I was introduced to some mathematics though : apparently the fastest "refresh rate" you will get out of a TFT is "1000(ms)/response" - my TFT's response time is 8ms, meaning it effectively has a refresh rate of 125hz - although it's only capable of 75hz according to control panel and a few tests
That would mean that the fastest my panel should be able to display a picture is 75 frames per second - (one frame every 13.3ms).
I'm not sure if that's entirely helpful or easy to understand, it has actually confuse me a little too. It could just be me misunderstanding the mathematics or it's just marketing bollocks - people giving "best case scenario" numbers instead of actual.
If theres any more info someone can shed I'm sure it would be useful
Shovel
Can't get enough of FH
- Joined
- Dec 22, 2003
- Messages
- 1,350
I can't say I know what difference it makes with just one screen, but I have 2: One connected via VGA and one by DVI.
If I have both outputs set to the same Refresh Rate, I get ghosting of one screen on to the other (I think the VGA screen is the one displaying the ghost). Changing one to 60Hz and the other to 75Hz fixes the problem.
I don't notice any difference between the two screens by eye (they're identical Fujitsu Siemens P19-2 screens).
Doesn't answer your question, but seemed related enough to be useful.
If I have both outputs set to the same Refresh Rate, I get ghosting of one screen on to the other (I think the VGA screen is the one displaying the ghost). Changing one to 60Hz and the other to 75Hz fixes the problem.
I don't notice any difference between the two screens by eye (they're identical Fujitsu Siemens P19-2 screens).
Doesn't answer your question, but seemed related enough to be useful.
Bonelamencer
One of Freddy's beloved
- Joined
- Jan 17, 2005
- Messages
- 1,060
The main difference between TFT and CRT monitors is that TFT don't flick regarding to its thin film tranzistors,that "hold on" signal till it gets refreshed.8ms doesn't show refresh time,it's response of active matrix(e.g. physical responce of liquid crystals).70Hz for TFT is more then enough for refreshing picture constantly.
Sends the lot.TdC said:
Also the reason you only get 60 or 70Hz offered is that the screen doesn't have enough bandwidth to process faster signals. This is especially true with DVI (unless you're running dual-link) as it has limited bandwidth also.
SheepCow
Bringer of Code
- Joined
- Dec 22, 2003
- Messages
- 1,365
- Thread starter
- #8
So in effect, if something changes you won't see it until:
1. One of the refrehes (done 60 or 70 times per second) occurs and
2. The monitor changes the voltage on the lcd to make the change visible,
3. The LCD actually changes
Whereas on a CRT you have
1. One of the refrehes (done 60 or 70 times per second) occurs and
2. Electron hits surface, but the entire screen is redrawn every refresh anyway
1. One of the refrehes (done 60 or 70 times per second) occurs and
2. The monitor changes the voltage on the lcd to make the change visible,
3. The LCD actually changes
Whereas on a CRT you have
1. One of the refrehes (done 60 or 70 times per second) occurs and
2. Electron hits surface, but the entire screen is redrawn every refresh anyway
- Joined
- Dec 22, 2003
- Messages
- 3,351
Isn't it annoying how people can't just get their heads together and agree on a standard - which will only help the end consumers. The numbers and facts and technical details are all well and good to those who understand them, but at the end of the day the average Joe in the street is just getting conned. The trouble is, it's been happening for years and is just an accepted way of life
