nanog mailing list archives
Re: Net Neutrality...
From: William Herrin <bill () herrin us>
Date: Fri, 18 Jul 2014 19:22:04 -0400
On Fri, Jul 18, 2014 at 6:48 PM, Owen DeLong <owen () delong com> wrote:
On Jul 18, 2014, at 11:35 , William Herrin <bill () herrin us> wrote:An LED screen doesn't refresh the way a CRT does, right? The light doesn't flash and fade, it stays constant until the next change. So why would a 30 hz refresh rate make any difference at all for tasks which update the screen less often than 30 times a second? Mike did say he used it for doing software development.However, the brightness of any particular color of any particular pixel in any LED screen is usually controlled by a process known as Pulse Width Modulation (PWM) where the LED actually turns on and off several thousand times per second and modifications of the ratio between the on-time and off-time in those cycles are used to control the apparent brightness. However, most "LED Screens" aren't actually LED screens, most of them are LED backlit CRT Screens. (I didn't look at the specs on this one in detail, so I don't actually know which type it is).
Hi Owen, You probably meant LED backlit LCD (liquid crystal display) screens, yes? As opposed to an LCD panel backlit with fluorescent tubes? LCDs don't have a flicker rate either, unless they're particularly badly implemented. http://en.wikipedia.org/wiki/LED-backlit_LCD_display Interesting point about PWM controlling the LED brightness, although that won't be tied to screen's overall refresh rate either. The pulse timing will be the same whether your overall refresh rate is 30 fps or 300. (And for those of you who don't bother turning off your flat panel monitors at night because what the heck, they won't burn in right?... That's a mistake. You won't hurt the LCD but the cold cathode fluorescent tube backlights are wearing out.) Regards, Bill Herrin -- William Herrin ................ herrin () dirtside com bill () herrin us Owner, Dirtside Systems ......... Web: <http://www.dirtside.com/> Can I solve your unusual networking challenges?
Current thread:
- Re: Net Neutrality..., (continued)
- Re: Net Neutrality... Graham Donaldson (Jul 16)
- Re: Net Neutrality... Barry Shein (Jul 16)
- Re: Net Neutrality... Valdis . Kletnieks (Jul 17)
- Re: Net Neutrality... Michael Thomas (Jul 17)
- Re: Net Neutrality... Rob Seastrom (Jul 18)
- Re: Net Neutrality... Michael Thomas (Jul 18)
- Re: Net Neutrality... William Herrin (Jul 18)
- Re: Net Neutrality... Paul S. (Jul 18)
- Re: Net Neutrality... Gary Buhrmaster (Jul 18)
- Re: Net Neutrality... Owen DeLong (Jul 18)
- Re: Net Neutrality... William Herrin (Jul 18)
- RE: Net Neutrality... Keith Medcalf (Jul 20)
- Re: Net Neutrality... Fred Baker (fred) (Jul 16)
- Re: Net Neutrality... Eric Brunner-Williams (Jul 16)
- Re: Net Neutrality... Doug Barton (Jul 16)
- Re: Net Neutrality... Collin Anderson (Jul 16)
- Re: Net Neutrality... Doug Barton (Jul 16)
- Re: Net Neutrality... Michael Hallgren (Jul 16)
- Message not available
- Re: Net Neutrality... Larry Sheldon (Jul 17)
- Re: Net Neutrality... Randy Bush (Jul 16)
- Re: Net Neutrality... joel jaeggli (Jul 16)