On 16/04/14 23:20, Gene Heskett wrote:
> On Wednesday 16 April 2014 09:09:06 Simon Wise did opine:
>> 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.
>
> We have a gismo thats basically much simpler than all that plumbing, to use
> when checking a cable for damage, called a Time Domain Reflectometer. The
> pro versions using a tunnel diode switch as a pulse generator, can tell you
> theres a bullethole in the line 883.6' out from where you are hooked up.
> I've made homemade versions using a pulse generator and a fast oscilloscope
> to measure the echo delay, punched some buttons on a good calculator and
> then told the tower crew where to open it up and replace a burned up
> connector bullet and/or the teflon disk holding it centered in the line.
> It got the job done so I figured it was good enough for the girls I go
> with. :)
not at all convinced that a fast oscilloscope, a good calculator and the
wet-ware connecting them are simpler than a bit of machined metal with gold
plating, but certainly re-using existing gadgets beats making new ones.
Simon
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Received on Thu Apr 17 08:15:02 2014
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