[ibis-interconn] Re: Noise parameter usage consistency
- From: <radek_biernacki@xxxxxxxxxxx>
- To: <ibis-interconn@xxxxxxxxxxxxx>
- Date: Thu, 14 Feb 2008 19:31:25 -0700
Hi Michael,
Starting with the last question - the answer is no. The theory for more than
two ports is still evolving, and in the future the syntax may have to be
extended to cover the general n-port noise data, but for now we should be ok
with 2-port data.
As far as my understanding of the existing statements is concerned, I do not
see any ambiguity in there. Nothing that is implied can overrule explicit
statements. The statement "before any noise parameters begin" is thus
applicable to the cases (and only to the cases) where such noise parameters are
permitted.
The proposed extension is ok, but it is just a restatement of an already
established rule. Furthermore the phrase "must also contain a [Number of Ports]
keyword" may actually be somewhat confusing - the [Number of Ports] keyword is
required in Version 2.0 files.
If we want, we may strengthen the Page 16 statement by saying that the noise
parameters are not permitted if the specified number of ports is different from
2 instead of "may only be included in 2-port network descriptions". Basically,
you can move the second sentence of your new text and merge it with the
statement on page 16.
Another solution: just remove [Number of Ports] from the statement on page 17.
Radek
________________________________
From: ibis-interconn-bounce@xxxxxxxxxxxxx
[mailto:ibis-interconn-bounce@xxxxxxxxxxxxx] On Behalf Of Mirmak, Michael
Sent: Wednesday, February 13, 2008 9:15 PM
To: ibis-interconn@xxxxxxxxxxxxx
Subject: [ibis-interconn] Noise parameter usage consistency
In the last Open Forum meeting, an inconsistency regarding Noise Parameters in
Touchstone 2.0's current draft was noted.
Page 16 of the PDF states:
"Noise parameters may be included in Touchstone(r) data files. However, they
may only be included in 2-port network descriptions."
Page 17 of the PDF implies that files containing network data for more than 2
ports can contain noise parameters:
"For Version 2.0 files, the [Number of Frequencies] and [Number of Ports]
keywords specify the size of the network parameter data expected before any
noise parameters begin."
As pointed out by Bob Ross, permitting noise parameter data in files containing
3, 4, etc. port network data would make the association of the noise data to
particular ports ambiguous.
To address this, I would like to strictly limit the use of noise parameter data
to 2-port Touchstone 2.0 files. Under this proposal, the text on page 17 as
noted above would therefore be changed to:
"For Version 2.0 files, the [Number of Frequencies] keyword specifies the size
of the network parameter data block expected before any noise parameters begin.
Version 2.0 files containing noise parameters must also contain a [Number of
Ports] keyword with '2' as its argument. Use of noise parameters in files
containing other arguments for [Number of Ports] is prohibited."
Comments?
Finally, could those with knowledge of Touchstone 1.0 tools answer the
following: did they ever permit noise parameter data to be used in 3-port
files? 4-port files? Etc.
- MM
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