[SI-LIST] AW: AW: Re: AW: S-parameter model from Datasheet
- From: "Havermann, Gert" <Gert.Havermann@xxxxxxxxxxx>
- To: "si-list@xxxxxxxxxxxxx" <si-list@xxxxxxxxxxxxx>
- Date: Wed, 7 Mar 2012 16:41:06 +0000
Ihsan,
your theory is correct, sorry for not beeing accurate enought in making my
point.
If you try match any model vehicle to s-parameter magnitudes, then fractions of
dB difference in RL can have huge differences in phase. That?s why I said it
can?t be done without knowing anything about phase, you will have a very hard
time to get a perfect match over wide frequency.
I?ve been down that road, and even with knowing the phase it is hard work. I
started using only magnitudes, and then I looked at the phase and I was way
off. Ever since then I check the phase too.
I have two s-parameter files of a transmission line where IL and RL are very
close, but the phase is off because the length of the traces is different while
impedance and losses were the same. If you (or others) are interested in seeing
those, I can send them privately.
BR
Gert
Von: Ihsan Erdin [mailto:erdinih@xxxxxxxxx]<mailto:[mailto:erdinih@xxxxxxxxx]>
Gesendet: Mittwoch, 7. März 2012 16:52
An: Havermann, Gert
Cc: si-list@xxxxxxxxxxxxx<mailto:si-list@xxxxxxxxxxxxx>
Betreff: Re: [SI-LIST] AW: Re: AW: S-parameter model from Datasheet
Gert,
A linear time invariant, causal and stable system needs to be minimum phase.
That means, for a realizable system, the magnitude data can't be haphazardly
associated with any phase. Indeed, the real and imaginary part of the s/z/y
whatever parameter must be the hilbert transform of each other for this system.
If you can build a stable, passive and causal model -be it a transmission line,
RC, RL or RLC network, whose s-parameters match the target data in magnitude
then the phase can't be wrong and the model is the true representation of the
system.
Regards,
Ihsan
On Wed, Mar 7, 2012 at 3:55 AM, Havermann, Gert
<Gert.Havermann@xxxxxxxxxxx<mailto:Gert.Havermann@xxxxxxxxxxx>> wrote:
Weston,
if you build a TL or RLGC model that just fits S11 and S21 magnitudes, how can
you ever be sure get the phase right, and how good is a model with wrong phase?
In addition, the curves in the datasheet don't come with a description of the
test setup they were taken with. Maybe there are some traces included, or the
solder joints and Package effects were de-embedded.
Chis' simulation would show wrong resonances of the discontinuities if the
phase is off, and if other information got wrong as well.
As I said, for good simulations results he needs either a vendor model from
omron, or he needs to measure the device by himself and then create a model
based on his measurements. For the latter, your method will work fine.
BR
Gert
----------------------------------------
Absender ist HARTING Electronics GmbH & Co. KG; Sitz der Gesellschaft:
Espelkamp; Registergericht: Bad Oeynhausen; Register-Nr.: HRA 5596; persönlich
haftende Gesellschafterin: HARTING Electronics Management GmbH; Sitz der
Komplementär-GmbH: Espelkamp; Registergericht der Komplementär-GmbH: Bad
Oeynhausen; Register-Nr. der Komplementär-GmbH: HRB 8808; Geschäftsführer:
Edgar-Peter Duening, Torsten Ratzmann, Dr. Alexander Rost
---------------------------------------------------------
Absender ist HARTING Electronics GmbH & Co. KG; Sitz der Gesellschaft:
Espelkamp; Registergericht: Bad Oeynhausen; Register-Nr.: HRA 5596; persönlich
haftende Gesellschafterin: HARTING Electronics Management GmbH; Sitz der
Komplementär-GmbH: Espelkamp; Registergericht der Komplementär-GmbH: Bad
Oeynhausen; Register-Nr. der Komplementär-GmbH: HRB 8808; Geschäftsführer:
Edgar-Peter Duening, Torsten Ratzmann, Dr. Alexander Rost
-----Ursprüngliche Nachricht-----
Von: si-list-bounce@xxxxxxxxxxxxx<mailto:si-list-bounce@xxxxxxxxxxxxx>
[mailto:si-list-bounce@xxxxxxxxxxxxx<mailto:si-list-bounce@xxxxxxxxxxxxx>] Im
Auftrag von Beal, Weston
Gesendet: Dienstag, 6. März 2012 20:40
An: si-list@xxxxxxxxxxxxx<mailto:si-list@xxxxxxxxxxxxx>
Betreff: [SI-LIST] Re: AW: S-parameter model from Datasheet
Cris,
The best option is to get a good model from the component vendor, but there are
other options. You can get a good approximation from a manually tuned circuit.
You know that the interconnect is mostly just a resistor, and the insertion
loss shows that it becomes more lossy with increased frequency. You can use a
small series inductance to model that. Start with a series resistor and
inductor. Simulate just this circuit with appropriate ports (including
impedances) and tune the resistor and inductor values to match the component
data that you have.
Another important thing to consider is the overall effect of this component on
your signal. If you change the inductor or resistor value of my suggested model
by a factor of 2 or 5, how much does that change the signal through the
complete channel? Maybe the fine accuracy of the relay model doesn't matter
much in the total model, and a good approximation gives you the information
that you need without spending a lot of time searching for or creating a super
accurate model.
Regards,
Weston
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx<mailto:si-list-bounce@xxxxxxxxxxxxx>
[mailto:si-list-bounce@xxxxxxxxxxxxx<mailto:si-list-bounce@xxxxxxxxxxxxx>] On
Behalf Of Havermann, Gert
Sent: Tuesday, March 06, 2012 7:40 AM
To: si-list@xxxxxxxxxxxxx<mailto:si-list@xxxxxxxxxxxxx>
Subject: [SI-LIST] AW: S-parameter model from Datasheet
Hi Cris,
if they can't provide you any models, you are srewed. The Plots don't show any
phase information, so you can't build your own S-Parameters. Without those it
is also impossible to create a behavioral model.
I think you have to get yourself a sample and test it if omron is not
willing/able to give you another model or at least phase information.
BR
Gert
----------------------------------------
Absender ist HARTING Electronics GmbH & Co. KG; Sitz der Gesellschaft:
Espelkamp; Registergericht: Bad Oeynhausen; Register-Nr.: HRA 5596; persönlich
haftende Gesellschafterin: HARTING Electronics Management GmbH; Sitz der
Komplementär-GmbH: Espelkamp; Registergericht der Komplementär-GmbH: Bad
Oeynhausen; Register-Nr. der Komplementär-GmbH: HRB 8808; Geschäftsführer:
Edgar-Peter Duening, Torsten Ratzmann, Dr. Alexander Rost
-----Ursprüngliche Nachricht-----
Von: si-list-bounce@xxxxxxxxxxxxx<mailto:si-list-bounce@xxxxxxxxxxxxx>
[mailto:si-list-bounce@xxxxxxxxxxxxx<mailto:si-list-bounce@xxxxxxxxxxxxx>] Im
Auftrag von Cristian Gozzi
Gesendet: Dienstag, 6. März 2012 15:39
An: si-list@xxxxxxxxxxxxx<mailto:si-list@xxxxxxxxxxxxx>
Betreff: [SI-LIST] S-parameter model from Datasheet
Hi folks
I have to use one RF-Relay for a 1.6Gbps diff.channel and I want to simulate
full path (driver + diif_pair + RF-RELAY + diff_pair + receiver)
I only got its datasheet with s-parameter plot (see link below) and I don't
have any model (neither S-parameter nor RLC model)
http://www.omron.com/ecb/products/pdf/en-g6ku-2f-rf.pdf
My question is: how can I include RF-RELAY model inside my channel?
The only thing I have in my mind is to create my own touchstone file and insert
value I can read from S-parameters plot in datasheet...
but I don't have any info about phase!
what can I do?
I appreciate your comment
Thanks
Cris
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Ihsan Erdin
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