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 Network Analyzers using PXI software

The Analyzer allows to save S-parameters to a Touchstone file. Files in this format are typical for most circuit simulator programs. The Touchstone file contains frequency values and S-parameters.

The Touchstone file saving function is applied to individual channels. Activate the channel to use this function (See Selection of Active Trace/Channel).

The *.S1P files are used for saving S11 and S22 parameters of a one-port device.

The *.S2P files are used for saving all four S-parameters of a two-port device.


note

If a channel does not have all the S-parameter traces, only available S-parameter responses will be represented. For example, if one S11 trace is enabled, the S21 response will be represented, and the S12 and S22 responses will not be represented. The missing S-parameters are displayed as zeroes in the file.

If full two-port calibration is active, all four S-parameters in a channel are measured, independently of the number of the traces.


The Touchstone file contains comments, header, and trace data lines. The header starts from the «#» symbol. Comments start from the «!» symbol. Comment contains following strings:

Model, serial number, software version.

Save date (in dd.mm.yyyy hh:mm:ss format).

The name of the saved parameters and their units.

The *.S1P Touchstone file for one-port measurements:

! Comments

# Hz S FMT R Z0

F[0]

{S11}’

{S11}”

F[1]

{S11}’

{S11}”

 

. . .

 

F[N]

{S11}’

{S11}”

The *.S2P Touchstone file for two-port measurements:

! Comments

# Hz S FMT R Z0

F[0]

{S11}’

{S11}”

{S21}’

{S21}”

{S12}’

{S12}”

{S22}’

{S22}”

F[1]

{S11}’

{S11}”

{S21}’

{S21}”

{S12}’

{S12}”

{S22}’

{S22}”

. . .

F[N]

{S11}’

{S11}”

{S21}’

{S21}”

{S12}’

{S12}”

{S22}’

{S22}”

Hz frequency measurement units (kHz, MHz, GHz);

FMT — data format:

RI real and imaginary parts;

MA — linear magnitude and phase in degrees;

DB — logarithmic magnitude in dB and phase in degrees;

Z0 — reference impedance value;

F[n] — frequency at measurement point n;

{…}’ — {real part (RI) | linear magnitude (MA) | logarithmic magnitude (DB)};

{…}” — {imaginary part (RI) | phase in degrees (MA) | phase in degrees (DB)}.

Touchstone File Saving

Touchstone typeTouchstone Type options

To select the saving type, use the following softkeys:

Save/Recall > Save Data To Touchstone File > Type

Then select the required Touchstone type:

1-Port (s1p)

2-Port (s2p)

 

Save Data to touchstone fileSelect Port (s1p)

To select the port number for one-port saving type, use the following softkeys:

Save/Recall > Save Data To Touchstone File > Select Port (s1p).

Touchstone format

Touchstone format options

To select the data format, use the following softkeys:

Save/Recall > Save Data To Touchstone File > Format

Then select the required Touchstone format:

Real-Imaginary

Magnitude-Angle

dB-Angle

 

Touchstone separator tab

To select the Touchstone separator type, use the following softkeys:

Save/Recall > Save Data To Touchstone File > Separator

Then select the required Touchstone separator:

Tab

Space

 

Including Trace Transform

If various transformations are applied to the active trace (for example, time domain gating, S-Parameter conversion, etc.), use the following softkeys to enable/disable the inclusion of trace transform:

Save/Recall > Save Data To Touchstone File > Including Trace Transform

NOTE: If the function is not enabled, the data is written to the file without conversion.

 

Save Data to touchstone file

Save file...

To save file to the hard disk, use the following softkeys:

Save/Recall > Save Data To Touchstone File > Save File…

Enter the file name in the dialog that appears.

 

 

 

Touchstone File Recalling

The Analyzer allows to recall data from the Touchstone files. Data can be loaded to memory traces or to data traces. When loading data to data traces, the Analyzer switches to  hold mode to avoid writing  over the recalled data with current data. When loading data to the memory traces, the sweep hold does not occur.

If the frequency scale of the Touchstone file does not correspond with the current Analyzer frequency settings, the user is prompted to choose between interpolating the data on recall or changing the Analyzer settings. The following message appears:

Warning_Touchstone_Recall

Load Data from Touchstone File blue

To Active Trace Memory

To All Traces Memory

To S-parameters

To load the data from the Touchstone file, use one of the softkeys:

Save/Recall > Load Data From Touchstone File

Then select the required data loading method:

To Active Trace Memory loading data to the active trace memory.

To All Traces Memory loading data to the memory of all traces.

To S-parameters loading data to all data traces of the channel.

 

 

 

 

Rev.:  22.3