On Sat, 19 Apr 2014 20:38:37 +0100, Vir Campestris wrote:

On 18/04/2014 13:39, Uncle Peter wrote:
On Fri, 18 Apr 2014 10:32:34 +0100, charles
wrote:

In article ,
Vir Campestris wrote:
On 16/04/2014 19:17, Uncle Peter wrote:

But the frequency we choose will have an effect on the number of
frames
a second on TV, the speed of motors, etc, etc. And those things we
like
to be metric.

This is obviously why NTSC TV uses 29.97 frames per second.


It was 29.94 in my day. Inflation affects everything.

AFAIK the Hz ain't that accurate, it fluctuates. But the electric board
are supposed to maintain a precise average for things like clocks that
are based on it (although I don't think anything is nowadays).

NTSC is that accurate. It's the mains that isn't.

And, yes, the mains is accurate over 24 hours.

So how did TVs work properly when they used the mains as a guide to frequency?

--
One of the first things you learn on your honeymoon is,
when you're carrying your bride over the threshold, always go in sideways,
unless of course two broken ankles and a concussion turn you on.