From: Chris Carlen
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Subject: Re: Who thinks this?
References: <3DC1D056.email@example.com> <3DC1F632.firstname.lastname@example.org>
Date: Fri, 01 Nov 2002 05:41:29 GMT
NNTP-Posting-Date: Thu, 31 Oct 2002 21:41:29 PST
Roy McCammon wrote:
> All close enough to true if the line is unterminated
> and the driver resistance not too low. Actually a
> series of stair steps, but looks like an RC on a slow
> scope. In fact, the same C as the capacitance per
> inch times the total inches.
> You got to chase the echoes.
Ah interesting, I hadn't quite connected the two together yet. Thanks
for that. The step envelope should look like a discretized RC.
Definitely a slow scope would fool one into thinking it was an RC. But
then the question points to the risetime of the steps. Why are they as
vertical as the driver straight into a resistor?
>> Of course all of these notions are very incorrect, assuming one is
>> talking about an almost ideal line with a purely real complex
>> propagation constant, and thus a purely real characteristic impedance,
>> and a non-dispersing, non-distorting line, such as typical controlled
>> impedance cables that we use every day.
>> What do you think?
> I think you forgot to add "terminated in its
> characteristic impedance" to that list.
Yes, or back terminated, as indicated in the examples that followed.
Christopher R. Carlen
Suse 7.3 Linux 2.4.10