[ibis-interconn] Re: Binary Touchstone Specification

  • From: "Elliott, Robert (Server Storage)" <Elliott@xxxxxx>
  • To: Walter Katz <wkatz@xxxxxxxxxx>, IBIS-Interconnect <ibis-interconn@xxxxxxxxxxxxx>, Gregory R Edlund <gedlund@xxxxxxxxxx>
  • Date: Fri, 26 Feb 2010 23:22:16 +0000

In Touchstone 2.0 we clarified that all three common line termination sequences 
are allowed:

c) line termination sequences -- LF (0Ah), CR+LF (0Dh + 0Ah) or CR (0Dh)

Just saying "\n or \r\n" is incomplete.  Macintoshes used \r alone for many 
years.


From: ibis-interconn-bounce@xxxxxxxxxxxxx 
[mailto:ibis-interconn-bounce@xxxxxxxxxxxxx] On Behalf Of Walter Katz
Sent: Friday, February 26, 2010 4:43 PM
To: IBIS-Interconnect; Gregory R Edlund
Subject: [ibis-interconn] Binary Touchstone Specification

All,

I took a little liberty and mad some minor modifications to Greg's original 
specification


Binary format touchstone files as defined by IBIS Touchstone 2.x add the 
statement to indicate binary format, the immediately following data is in 
binary instead of ASCII.  :

       % BINARY DL
       % BINARY DB
       % BINARY FL
       % BINARY FB
       % BINARY ML
       % BINARY MB

The format specifier convention is as follows :
      D : double
      F : float
      M : double freq, float data
      L : little-endian
      B : big-endian

Thus DL is double, little-endian.

The above line can be followed by a \n or a \r\n to indicate newline. 
Immediately following the newline sequence is one pad 0 byte which indicates 
the following data is binary format numbers.



In addition to the above codes DL, DB, FL, FB, ML, MB we can add

FFL FDL SQL DFL DDL DQL QFL QDL QQL FFB FDB FQB DFB DDB DQB QSB QDB QQB

The conventions for these new codes would be
First Character Precision of Frequency
F Single Precision 32 bits
D Double Precision 62 bits
Q Quad Precision 128 bits
Second Character Precision of Data
F Single Precision 32 bits
D Double Precision 62 bits
Q Quad Precision 128 bits
Third Character Little/Big Endian
L Little Endian
B Big Endian

So QDB would be 128 bit frequency, 64 bit data, big endian.

The following cases would be identical
DL    DDL
DB    DDB
FL    FFL
FB    FFL
ML    DFL
MB    DFB

An if memory serves me correctly, the only other things were that there would 
be no [End] termination record for the Network Data, and that 2-Port Touchstone 
Files cannot have noise data when using the % BINARY option.

Walter


Walter Katz

303.449-2308

Mobile 720.333-1107

wkatz@xxxxxxxxxx

www.sisoft.com

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