[LAU] hardware - Intel CPUs

[Simon Wise]

On 16/04/14 17:19, david wrote:

>
> Interesting. What is the difference between speed of sound in air and the speed
> of electricity through a cable?

sound is about 3ms per metre (330 m/s) in air

  ... in a room, talking about sound, there is no significant delay for the 
signal in the cable ... from Sydney to Hawaii via copper or fibre yes, 
considering phase differences for RGB video signals in a building yes, talking 
about timing on a circuit board or a bus while syncing gigahertz clocks yes, but 
for sound within a building the speed over copper may as well be infinite.


I was shown a rather nice artwork that used high resolution radar (resolutions 
around 1 centimetre I think) to get positions (it was made in a university 
robotics department that had such things!). The way those work is very 
interesting ... the frequencies are way to high to digitise, so the electronics 
has to be all analogue ... the 'circuitry' is basically plumbing ... gold lined 
tubes and chambers using resonances and such to measure delays and phase 
differences. At those frequencies the speed of light becomes a dominant 
consideration.


Simon