From: "Michael Rigby-Jones" <Michael.Rigby-Jones@BOOKHAM.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Thursday, February 20, 2003 5:47 AM
Subject: Re: [PIC]: How would I build a reflectometer?


> > There might be some way the pulse transit time on the cable might be
made
> > into a sort of oscillator circuit.
> >
> That's basicaly what Wagner suggested a few posts back.  I was
thinking you
> could perhaps do away with pulse reflections all together and just use
cable
> capacitance with some calibrations for cable type.  It might be able
to be
> made accurate enough for some applications, but TDR is the way to go
for
> real accuracy.

I was thinking about this approach.  I've seen it referred to as a
"gimmick" capacitor.  I didn't know how much effect the "real world"
might have on it though (fluorescent lights, noise, etc..).  I will do
some experiments at various customer sites that are wired using the same
cable type.  I already know the lengths there as well.

michael

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