[SI-LIST] S-Parameter view for multiDrop bus
- From: Hermann Ruckerbauer <Hermann.Ruckerbauer@xxxxxxxxxxxxx>
- Date: Thu, 11 Dec 2014 10:45:48 +0100
Hello Experts,
I struggeled with this one several times in the past and maybe somebody
has some answers ..
Even with todays standards that go P2P serial there are still some
multidrop things out there.
The flyby bus of DDR3/4 is one example.
I often use S-Parameter e. g. in order to check behavior of a
transmission path, but for multidrop configuration this is difficult.
Generated are these S-parameters usually having a port on each position
of the DRAMs. This allows to use the model for simulation.
But when looking to the S-parameters in a viewer they are diffictult to
interprete, as these multiple terminations are not the normal usage case.
In the real application you have a driver where you can place a port,
but the termination is at the end of the bus.
So the closest I can get there is to re-simulate have in a port at the
driver and one DRAM. But these S-parameters do have still 3 terminations
in and so if I view them they are still different to the real world
application.
And i need to generate data for each of the DRAM positions separately
what I don't like.
Does anybody have a nice solution how to display/transform the data in
order to get a reasonable view of the transmition behavior to each of
the DRAMS ?
Maybe Touchstone 2.0 would be an option ..
This allows multiple Reference Resistance values, so placing a 10k port
at each of the DRAM positions looks like a possible solution.
But my first trials with different port impdeances did not result in
reasonable results .. (not sure why) ...
Any idea on this one ?
thanks and regards
Hermann
EKH - EyeKnowHow
Hermann Ruckerbauer
www.EyeKnowHow.de
Hermann.Ruckerbauer@xxxxxxxxxxxxx
Itzlinger Strasse 21a
94469 Deggendorf
Tel.: +49 (0)991 / 29 69 29 05
Mobile: +49 (0)176 / 787 787 77
Fax: +49 (0)3212 / 121 9008
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