"Phil Burns" <philNOSPAM@ics.mq.edu.au> a écrit dans le message de
news:blgnqi$8es$1@sunb.ocs.mq.edu.au...
Just a quick question... Has Mathew Orman's FTL transmission lines
revolutionised communications yet? I haven't heard anything about them
in the media.
There was a thread on FTL hoax in March. I don't retrieve the original post, so
here is a copy of Gilbert Mouget's post about Orman's measurement error :
"Gilbert Mouget" <no.spam@thank.you> wrote in message
news:MPG.18eea3489002c3af989c43@news.free.fr...
In article <MPG.18edacd1dfae53d5989c40@news.free.fr>,
dated Fri, 28 Mar 2003 00:51:04 +0100,
Gilbert Mouget, <no.spam@thank.you> says...
-A) 1 MHz sinewave, no termination :
2m of coaxial with velocity coefficient of 0.66 gives a 3.6° phase shift
at 1 MHz. Since there is no termitation we have 100% reflexion in phase
at probe 2.
So, if the signal output of the generator is sinA, the signal at probe 2
is sin(A+3.6°) + sin(A+3.6°) = 2sin(A+3.6°) . This means that if a 50ohms
generator is set at 1 volt pp we have 2 volts pp at probe 2.
At probe 1 we have the sum of the incident and delayed reflected signal
sinA + sin[A+(3.6°x2)] = sinA + sin(A+7.2°)
sinA + sinB = 2 cos[(A-B)/2] sin[(A+B)/2] hence,
sinA + sin(A+7.2°) = 2 cos [-7.2°)/2] sin[(A+A+7.2°)/2] =
1.996 sin (A+3.6°) , slightly lower but exactly in phase with the
voltage at probe 2 which is 2sin(A+3.6°).
Quoting Mathew Orman's website :"There delay now should be from
400ps to 800ps dependent of quality of coax that you have."
I have clearly shown that there should be no delay at all.
There is no delay between probe 1 and probe 2, but, since the
reference is the generator, sinA, the signal at the probes is
retarded 3.6° or 10ns.
Someone marcketting "10 GBit/sec UFTL Data Transmission Cable"
should have been able to notice this 10ns delay betwen the
generator reference trigger and the signal at the probes.
FG
.
