[SI-LIST] : RE: [SI-LIST]: Long bus or star?

Bob Perlman (bobperl@best.com)
Mon, 05 Apr 1999 12:53:44 -0700

Hi -

> It seems that the rise time would be that of the incident wave until the
>reflection hits (almost immediately as mentioned), then be doubled as the
>two waves converge and sum, then be that of the incident wave again as the
>residue reflection completes.

In the ideal case, where we discount the effects of any capacitance at
the
end of the line, the risetime at the end of the line is the same as the
risetime of the incident signal, but the amplitude, and therefore the
edge
rate, are doubled. The reflected wavefront is launched as the incident
wavefront arrives, effectively doubling the amplitude without affecting
the
risetime.

Add capacitance and the risetime will be degraded.

We (this writer included) tend to use the terms "risetime" and "edge
rate"
interchangeably, but they're two different animals.

Bob Perlman Cambrian Design Works =========== Bob Perlman Cambrian
Design Works
Digital design and signal integrity consulting
http://www.best.com/~bobperl/cdw.htm

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