What does this mean in ADS --> stoy(S[1：：2，1：：2])

Hi everyone,

I am trying to study about S parameters in ADS. I have seen from a file that in the "stoy" function, there is a variable defined in Mea Eqn as follows:

Param_y = stoy(S[1::2,1::2]).

In the schematic, there is an element called "S2P" driven by two ports Port 1 and Port 2. I guess that this is to transform S paramters to Y parameters. But, what does the syntax

S[1::2, 1::2] mean ?

Could someone explain to me please ?

Thank you very much,

DYL

"::" works as followings in Agilent ADS Measurement Expression.

(1) Sequence Operator
(2) Wildcard Operator

See http://edocs.soco.agilent.com/displa...nt+Expressions

In your case, "::" works as Sequence Operator.

Don't you have typo ?
If this is not typo, this means {S11, S12, S21, S22}.
http://edocs.soco.agilent.com/displa...duction+to+AEL

Measurement Expression is a subset or special version of AEL.
This relation is similar to a relation between Ocean and Skill in Cadence DFII.

Where do you refer this equation from ?

http://edocs.soco.agilent.com/displa...009/stoy%28%29

S parameters to Y parameters conversion function..

Hi pancho_hideboo and BigBoss,

Thank you very much for your answers. It helped me a lot. Actually, I saw this example from an ADS file existing in my group. For the moment I don't have chance to contact the author, that's why I posted my question here.

However, in case that I would like to see the details of the "stoy" function, how could I open it from the link below ?

================================

Defined in

SHPEESOF_DIR/expressions/ael/network_fun.ael

================================

Can I open the "network_fun.ael" with a text editor ?

Thank you very much,

DYL

You must not write "S[1::2,1::2]".

S parameters are matrix, here you have to use "()" not "[]".
Does "Param_y=stoy(S[1::2,1::2])" truely work correctly ?

Write "Param_y=stoy(S)" not "Param_y=stoy(S[1::2,1::2])".

Again see http://www.designers-guide.org/Forum...66403928/30#30

Yes.

Hi pancho_hideboo,

Ahh, yes, you are right. I actually use "S(1::2,1::2)" in my ADS, not S[1::2,1::2]. Thank you very much for your comment and explanation.

DYL

Even if so, you must not use "S(1::2,1::2)".

Again answer my question.
Does "Param_y=stoy(S(1::2,1::2))" truely work correctly ?

Again write "Param_y=stoy(S)" not "Param_y=stoy(S(1::2,1::2))".

Hi pancho_hideboo,

Yes, using "Param_y=stoy(S(1::2,1::2))" is working correctly. Here I compared the answer I got from ADS with a calculation I wrote in Mathcad to perform S-to-Y conversion. The answers are the same.

In the schematic, there are two networks, i.e., one being connected to Port 1 and Port 2 and the other one being connected to Port 3 and Port 4.

I think that to convert the S parameters of the network connected to Port 1 and Port 2 to Y parameter, we need to specify the ports, so that we use S(1::2,1::2).

Is my reason correct ?

DYL

I don't think your 2x2 Y-matrix is appropriate.
Consider termination conditions of ports for Y-parameters.
Y-Parameres are defined as short termination at ports.

Your 2x2 Y-matrix is under condition of port3 and port4 as not shorted.

You can apply stoy() for N ports.

So even if there are four ports in your schematic, Y=stoy(S) is valid.

If you have interest in any two port Y-parameters, you can extract and build new 2x2 Y-matrix.

For example, assume port-1 and port-3 as ports which you have interest in.

Ynew={Y(1,1), Y(1,3), Y(3,1), Y(3,3)}.

Here Y ; 4x4, Ynew ; 2x2

In your case, renumbering of Y-parameters is not required, so you can use 4x4 Y directly.

He wrote that there are two independent 2-port networks on ports 1,2 and ports 3,4

May be my explanation was not clear enough. Yes, I have two independent 2-port networks, one being connected to Term 1 and Term 2 and the other one being connected to Term 3 and Term 4.

DYL

See http://www.designers-guide.org/Forum...1279385505/3#3

Thanks, pancho_hideboo,

I have followed the link.

DYL

申明：网友回复良莠不齐，仅供参考。如需专业帮助，请学习易迪拓培训专家讲授的ADS视频培训课程。