[ntp:questions] Visual clock display?

Chris Albertson albertson.chris at gmail.com
Sat Aug 25 18:34:08 UTC 2012

The limit of accuracy of the visual clock is the refresh rate of the
monitor.   One the old CRT monitors there was a vertical sync that ran at
about 60 to 100 Hz.  I think LCDs have something like this too.   You can
do better than 100 mSec using your method.  In fact it can approach the
vertical sync limit.

The system can do better timing but the 100 Hz (or so) screen refresh is
the limit.  Actully you eyes can't see a change that is faster than about
maybe about 30 mSec.  But you CAN see 100 mSec ticks.  Run your update loop
at 100Hz and you will be fine

On Sat, Aug 25, 2012 at 10:56 AM, Ralph Aichinger <ralph at pangea.at> wrote:

> This might be a stupid question:
> What is the best way to visually display the current time of
> the local ntp server? Currently I am using a small program that
> uses gettimeofday on my Linux host. As I only want about 100
> milliseconds precision, I should be fine.
> But is there a "proper" way to display the time of a ntp server
> continuously on the screen (for timing a clock via photo/video)?
> /ralph
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Chris Albertson
Redondo Beach, California

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