Arpad,
Here is an example. I have tools that read and write Touchstone I files. All I
want to do is create and read Touchstone file that have the Impedance per port
record. I and just add the following two lines:
[Version] 3.0
[Reference] ...
All I need to do is modify my Touchstone reader to ignore the "[Version] 3.0"
line and parse the "[Reference] ..." line.
There is no need to add the [Number of Ports] because it is in the sNp file
extent.
There is no need to add the [Number of Frequencies] since my parser already
knows how to parse it.
There is no need to add [Network Data], since my parser already knows how to
parse it.
If, and when we add [Begin Port Data] and [End Port Data], it will be easy to
modify parsers to just skip that section, or the user can chose to delete those
lines from the file to use in their tool.
The whole idea is make it easy for people to add the additional information
that we know is desired today, which is keep sNp, add [Reference] and add
machine parsable Port information.
I personally would like to eliminate Touchstone 2 altogether, and come up with
a Touchstone Interconnect standard based on Touchstone 1.
Remove the following keywords
* [Number of Ports]
* [Number of Frequencies]
* [Number of Noise Frequencies] (No support for Noise Data)
* [Mixed-Mode Order]
Optional keywords (Sorted by most important first)
* [Reference]
* [Begin Port Data]/[End Port Data]
* [Begin Sparse Data]/[End Sparse Data]
* [Begin Information]/[End Information] (optional)
* [Two-Port Order]
* [Matrix Format]
This is what the user community wants
* They require the sNp format, so why have [Number of Ports]
* The already know how to figure out [Number of Frequencies]
* Interconnect does not use Noise Data
* No need for Mixed-Mode Order, mixed mode s-params can always be generated
from normal single ended order and [Port Data]
* The most important things that are needed over Touchstone I are:
* [Reference]
* Computer parsable Port Data
* Sparse Data
Bottom lines is we have the following options:
1. Create a Touchstone 3 based on Touchstone 2 without the upward
compatibility clause
2. Create a Touchstone 3 based on Touchstone 2 with the upward compatibility
clause
3. Throw away Touchstone 2 and create a Touchstone Interconnect as suggested
above.
Walter
Walter Katz
Work 508.647-7633
Cell 720.417-3762
[Description: Description: Visit MathWorks.com]
From: ibis-interconn-bounce@xxxxxxxxxxxxx <ibis-interconn-bounce@xxxxxxxxxxxxx>
On Behalf Of Muranyi, Arpad
Sent: Sunday, January 9, 2022 3:25 PM
To: 'IBIS-Interconnect' <ibis-interconn@xxxxxxxxxxxxx>
Subject: [ibis-interconn] Re: Touchstone 3 draft1
Walter,
I am trying to understand what this upward compatibility is really doing for us
in practice:
"Changing [Version] to any value greater or equal to the maximum value of the
current version and 3.0 is legal."
I understand that your problem with Touchstone 2 is that you can't add the
[Version] 2
keyword to a Touchstone 1 file and parse it successfully with the parser. I
also understand
that what you propose for Touchstone 3 supposed to work that way, i.e. adding
[Version] 3
to a Touchstone 1 file would parse without error with a proposed Touchstone 3
parser.
I mentioned in the Open Forum meeting last Friday that the current Touchstone 2
parser
has the ability convert Touchstone 1 files to Touchstone 2 format, and parse
them without
error. Your reply to that was that the problem is that there are a gazillion
scripts and
home-made tools out there which only work with Touchstone 1 format, and they
would
be all broken with Touchstone 2 files, and that's why we need to retain the
Touchstone 1
format.
Now, having said all that, let me ask what happens when someone adds [Version] 3
to a Touchstone 1 file. I understand that it will parser without errors in the
Touchstone 3
parser. But will they still work with all those scripts and home-made programs
you want
to support? I think the presence of the [Version] keyword will kill them.
Then what is the
advantage of this upward compatibility for those scripts and tools?
If you say, those scripts and tools will continue to work in writing Touchtone
1 files and
the only thing people would have to do to the files they write is to add the
[Version] 3
keyword, then I would say with the same effort they take to add the [Version] 3
keyword,
they could also use the parser and convert the freshly created Touchstone 1
file into a
Touchstone 2 file.
In short, I don't understand yet why we need to undo everything in Touchstone 2
to go
back to the Touchstone 1 format. Please educate me on that...
Thanks,
Arpad
=========================================================================
From:
ibis-interconn-bounce@xxxxxxxxxxxxx<mailto:ibis-interconn-bounce@xxxxxxxxxxxxx>
<ibis-interconn-bounce@xxxxxxxxxxxxx<mailto:ibis-interconn-bounce@xxxxxxxxxxxxx>>
On Behalf Of Walter Katz
Sent: Friday, January 7, 2022 3:04 PM
To: 'IBIS-Interconnect'
<ibis-interconn@xxxxxxxxxxxxx<mailto:ibis-interconn@xxxxxxxxxxxxx>>
Subject: [ibis-interconn] Re: Touchstone 3 draft1
Please ignore the last version (forgot to save before e-mailing it out)
Walter
Walter Katz
Work 508.647-7633
Cell 720.417-3762
[Description: Description: Visit MathWorks.com]
From: Walter Katz
Sent: Friday, January 7, 2022 4:02 PM
To: 'IBIS-Interconnect'
<ibis-interconn@xxxxxxxxxxxxx<mailto:ibis-interconn@xxxxxxxxxxxxx>>
Subject: Touchstone 3 draft1
All,
The enclosed Touchstone 3 specifications contains changes that
1. Touchstone I files upgraded to [Version] 3.0 will be legal Touchstone 3
files with no other changes.
2. Adding [Reference] could be done without adding any other Touchstone 2
keyword.
3. I added a section that contains a detailed algorithm on how to parse
Touchstone 3 files.
4. I added a futures sections outlining
* Sparse Data implementation
* Port information
There are several issues that need to be discussed:
1. Normalizing data
2. 2-port order
3. Network Data row organization
Walter
Walter Katz
Work 508.647-7633
Cell 720.417-3762
[Description: Description: Visit MathWorks.com]