Hi Tom,
The reason I mentioned terminating each end of the victim line is that if
the
victim line lacks proper termination, it can cause the crosstalk signal at
one
end of the line to get reflected (either completely or partially) and travel
to the other end of the line.
This can lead to undesirable effects.
For instance, in case of stripline, FEXT can be almost zero, if the line is
properly terminated. However, in case of poor termination, the NEXT noise
can get reflected back from the near end of the line and result in
far-end crosstalk.
Thank you,
Abe
On Mon, Jun 19, 2017 at 3:14 PM, Tom Dagostino <tom@xxxxxxxxxxxxxxxxx>
wrote:
Abe
Your comment : " A crosstalk simulation of a topology consisting of an
aggressor line and a victim, usually requires terminating both ends of the
victim line."
I think should read more along the lines of "any simulation should have the
ends of the nets terminated as they are on the DUT of interest." If the
victim is a source only terminated line there is no reason to terminate the
victim in the simulation.
Thoughts?
Tom Dagostino
971-279-5325
tom@xxxxxxxxxxxxxxxxx
Teraspeed Labs
9999 SW Wilshire Street
Suite 102
Portland, OR 97225
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On
Behalf Of Abe Riazi
Sent: Monday, June 19, 2017 2:48 PM
To: Hermann.Ruckerbauer@xxxxxxxxxxxxx
Cc: aakash6164@xxxxxxxxx; si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: NEXT and FEXT Profile for a Pulse
Hi,
Since crosstalk is such an important topic in field of signal integrity,
numerous tools and methodologies have been developed for analysis of
crosstalk effects.
For instance, there exist rules of thumb, mathematical equations and
calculators for obtaining a first order estimate of crosstalk noise.
There are also tools such as HSPICE, Ansys/Ansoft Designer, HyperLynx,
MATLAB/Simulink, etc., which allow a more accurate simulation of FEXT and
NEXT, both in time and frequency domains.
A crosstalk simulation of a topology consisting of an aggressor line and a
victim, usually requires terminating both ends of the victim line.
Furthermore, in order to ensure validity of the simulation setup and
results, it is recommended that:
I. Vary the coupling length. As the coupled length is increased, crosstalk
noise should also increase.
ii. Vary separation between the aggressor and victim lines. As separation
is
increased crosstalk noise should diminish (and vice versa).
iii. Evaluate effectiveness of trace terminations.
Frequently, the ultimate test for assessing the accuracy of a simulation
outcome is to correlate it with measurement results. A discrepancy between
simulated and measured data usually indicates that an improvement is
required in the modeling or simulation setup (assuming that the measurement
result is reliable/accurate).
Kind regards,
Abe
On Sun, Jun 18, 2017 at 1:45 AM, Hermann Ruckerbauer <
Hermann.Ruckerbauer@xxxxxxxxxxxxx> wrote:
Hello,helpful.
I guess there is no need for expensive Tools, I guess QUCS should do
the job, and most likely LTspice as well.
Please correct me if I'm wrong in the assumption that these tools can
handle the job.
I would also assume, that you can check FEXT/NEXT with imperfect
termination e. g. on the Victim line where you would see reflected
crosstalk waves.
Hermann
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Am 16.06.2017 um 02:33 schrieb Aakash Gupta:
Hello Experts,to
I am studying cross talk and I see many resources online showing the
profile of NEXT and FEXT for a step signal (rising edge only). I
totally get that.
I want to know what is the cross talk profile for a pulse (rising
and falling edge). I have some picture in my mind but I cannot
afford tools
simulate and verify my intuition.
If some has them simulated or could explain me. It will be very
Thanks
Aakash.
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