begin  quoting Tracy R Reed as of Fri, Nov 18, 2005 at 04:36:19PM -0800:
> Stewart Stremler wrote:
> > I thought it was jitter?  I thought the ear could handle dropouts, but 
> > time-variance turned it all into noise?
> 
> True, jitter can be a problem also. Usually you digitize and send in
> 20ms packets or 50 per second. So you may not notice a few dropped
> packets, especially if they don't all happen at once. And normally if
> packets arrive out of order they are dropped. There might be algorithms
> for trying to smooth over dropped packets, I'm not sure. But VOIP
> implementations can and often do try to measure latency and implement a
> jitter buffer. It adds a bit of latency depending on how big the buffer
> is but it works similar to a buffer on a CD player (remember CD players
> and skipping?) so that by adding a little delay the buffer can put
> packets back in order and play them at a continuous speed so the ear
> does not hear any errors. But if latency varies too widely (jitter) the
> buffer could run out or overflow and cause drops.
> 
> > Do I have that backwards?
> 
> You have it right. I just expounded a little more above for the benefit
> of others.
> 
> > /me thinks of _Ender's Game_
> 
> Oh, to have faster than light transmission capability... But I would
> settle for having a pair of entangled particles. Imagine if we could

I haven't been keeping up on my reading about entangled particles. The
"spooky" part of 'spooky action at a distance' was supposedly FTL,
wasn't it?

> construct point to point links to anywhere in the universe by just
> meeting up with a friend, exchanging entangled particles, and keeping
> our collection of entangled particles with us wherever we went. Instant
> fast, unstoppable, and unsnoopable bandwidth.  Sure, there would still be
> lightspeed latency, but you it would be one heck of a p2p network.

Much simpler to simply generate a one-time pad.  Entangled particles
have to be kept safe from the rest of the universe so they don't
decohere on you.

"What we chiefly need..."

A good source of random noise and a DVD burner... and some simple
software to keep a database of what bits you've used...  most of the
actual work would be in the management side of it.

...but then you're back to the killer problem of cryptography - key
distribution. Entangling the particles comes in here.

(This would actually be a fun project to do. Which means it's probably
already been done with someone with more spare time than I seem to have...)

-Stewart "And a good source of real randomness." Stremler


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