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****************** TSCHK TOUCHSTONE PARSER BUG REPORT FORM ****************
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INSTRUCTIONS

To report a bug in the TSCHK Touchstone Parser.  Please fill out the top part
of the following form and send the complete form to info@ibis.org.

A list of reported bugs is maintained at http://ibis.org/bugs/tschk.

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PARSER VERSION NUMBER: 2.0.0

PLATFORM (SPARC, HP700, PC, etc.): PC

OS AND VERSION: Windows 10

REPORTED BY: Randy Wolff, Micron Technology

DATE: January 15, 2021

DESCRIPTION OF BUG:

TSCHK2 was used to attempt conversion of a Touchstone 2 file to a
Touchstone 1 file with the following command:

tschk2.exe -canonical-v1 bug4.ts > bug4.s2p

and the output was:

tschk2: failed to write Touchstone v1 file: Touchstone v1 only supports a 
single reference impedance

It looks like the conversion routine doesn’t recognize that this line in
the Touchstone 2 file:

[Reference]    50.0   50.0

is still a single reference impedance.  I think any use of the [Reference] 
keyword breaks the conversion, as it assumes it is being used to show
different per-port impedances.  For this file example, adding a “!” comment
to the [Reference] line allows for a successful file conversion.

A simple enhancement would check the [Reference] line to see if all values 
are the same, in which case it could go forward with the conversion. 

Comment, the check would be only for exact numerical matching. So 50.0 is
different than 49.99999999.

INSERT TOUCHSTONE FILE DEMONSTRATING THE BUG:

*******
bug4.ts
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! NPort=2 DATA=1 NOISE=0 GROUPDELAY=0 COMPLEX_DATAFORMAT=DB
! Ports List
! Port#  Port Name
! 1      IN
! 2      OUT
!
[Version] 2.0
# Hz S DB R    50.0
[Number of Ports] 2
[Two-Port Data Order] 12_21
[Number of Frequencies] 3
[Reference]    50.0   50.0
[Matrix Format] Lower
[Network Data]
1   -27.78  0.161  -0.397  -0.007   -27.63   0.157
5   -27.73  0.270  -0.399  -0.030   -27.59   0.248
10  -27.72  0.253  -0.400  -0.048   -27.58   0.216
[End]

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******************** BELOW FOR ADMINISTRATION AND TRACKING ***************
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BUG NUMBER:  4

SEVERITY: [FATAL, SEVERE, MODERATE, ANNOYING, ENHANCEMENT]  ENHANCEMENT

PRIORITY: [HIGH, MEDIUM, LOW]                               LOW

STATUS: [OPEN, CLOSED, WILL NOT FIX, NOT A BUG]             CLOSED

FIXED VERSION:  2.0.1

FIXED DATE:     August 12, 2021

NOTES ON BUG FIX:
Classified at the January 29, 2021 IBIS Open Forum.  To be fixed in a
later release

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