[SI-LIST] Re: TDR and line losses
- From: "Dima Smolyansky" <Dima.Smolyansky@xxxxxxxxxxxxxx>
- To: <Suresh.Subramaniam@xxxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
- Date: Fri, 21 Nov 2003 14:22:19 -0800
Suresh,
The upward slope of the TDR trace is indicative of losses. However, the
losses will need to be quite substantial for the upward "creep" to be
clearly visible. In other words; your transmission trace (TDT) will show
even fairly small losses through rise time amplitude degradation; however,
when you begin to see the "creep" in the reflection (TDR), that will show up
as large rise time and amplitude degradation in TDT.
Also, Howard Johnson did an article once, where he played with skin effect
and dielectric loss, and showed how they affect different portion of the TDT
waveform. You can do the same in IConnect's lossy line model by varying the
skin effect and dielectric loss parameters independently, and evaluating
their effect on the TDT (or TDR) waveform.
Thanks,
-Dima
----- Original Message -----
From: "Suresh Subramaniam" <Suresh.Subramaniam@xxxxxxxxxx>
To: <si-list@xxxxxxxxxxxxx>
Sent: Friday, November 21, 2003 2:00 PM
Subject: [SI-LIST] TDR and line losses
>
> If I TDR (rise time 26ps) a long lossy transmission line, should I expect
> the impedance profile to gradually creep up to a higher value (assuming I
> start out with a 50 Ohm impedance?). In other words, how does the TDR
> take into account the effect of losses?
>
> Thanks
> Suresh
>
>
>
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