Save and Recall a File

You can save and recall files to and from an internal or external storage device in a variety of file formats.

• How to Save Instrument State

• How to Save Measurement Data

• How to Recall a File

• About Instrument State and Calibration Data ( .csa, .cst, .sta, .cal)

• About Measurement Data Files (.prn, .snp, .cti, .csv, .mdf)

• Managing Files without a Mouse

Other Data Outputting topics

Save VNA Measurement Data

Note: Before saving measurement data, always trigger a single measurement, and then allow the channel to go into Hold.  This ensures that the entire measurement trace is saved.

Note: Memory traces  can only be saved in select file types (CTI, CSV, MDF) when the “Scope” data setting is set to “Displayed Traces”.

Save in Allows you to navigate to the directory where you want to save the file.

File name  Displays the filename that you either typed in or clicked on in the directory contents box.

To select a file type and change data settings, press File Type… to launch the File Type dialog:

File Type  Choose from: (click each to learn more about each file type):  *.prn, *.SNP, *.SNPX. *.cti (citifile), *.csv, *.mdf.

• FCA, GCA, Swept IMD, and Swept IMDx data can be saved to a special csv format. Learn how (FCA, GCA - Swept IMD)

• S2P Noise Parameters (*.s2p) Trace and Noise Parameters (*.snp) - Save the noise figure parameters and S-parameters. Learn more.

• To save the screen as .bmp, .jpg, or .png graphics file types, click File / Print / Print to File.  Learn more.

Data Settings

This selection refers to the data processing stage of the data flow diagram:

1. Post-processing: Includes equation editor, trace math, gating, phase correction, magnitude offset, and smoothing.

2. Legacy gating issue: When saving SnP files with correction enabled and with gated S-Parameters, but not all S-Parameters are displayed on the channel, the gating applied to the saved S-Parameters may be unpredictable.

3. SnP Equation Cached Parameters: When no correction is applied, S-Parameter(s) present in any equations on the channel will have their uncorrected data cached in memory. These cached S-Parameters exist and are used to save SnP files, even if they are not displayed on a trace. The parameters in the equation overwrite the underlying parameter (the original measurement parameter before the equation was applied), meaning the underlying parameter’s uncorrected data is no longer in memory. However, if there are no parameters in the equation, the underlying parameter will not be overwritten. If a correction is applied, all the S-Parameter data will exist in memory, regardless of whether it is displayed or not.

Example: User saves S2P with ports 1,2 selected with no correction applied 

Note: The user may independently select the format of the data saved, so the data may not match the format of the displayed trace.

Recall a file

Instrument State / Calibration Files

You can save, and later recall, instrument settings and calibration data for all channels currently in use on the analyzer.

An Instrument State contains almost every analyzer setting. The following settings are NOT saved and recalled with Instrument State:

• GPIB address

• RF power ON/OFF (depends on current setting)

The following file types are used to save and recall instrument states and Cal Set information:

File Type Descriptions and Recall

The following describes each file type, and what occurs when the file type is recalled.

Instrument states can have the following suffixes: .sta, .cst, and .csa.

Common to all of the instrument state files is the state of the instrument including the quantity and content of channels, traces, windows, markers, limit lines, etc.

What is different about the instrument state files is the way they handle the calset - a calset is the set of data that results from having executed a calibration on a channel.

Compatibility of Files

• There is no compatibility among the VNA family products. For example, ENA cannot recall the state file which is saved by PNA and PXI/USB VNAs.

• The analyzers cannot recall file saved by that with the smaller number of port. For example, 2 port VNAs cannot recall the files saved by 4 port VNAs.

• When the installed option is different, recalling the file may fail.

• Files that are saved with later firmware revisions may not be recalled by prior firmware revisions.

*.sta files

• Contain ONLY instrument state information - NOT Cal data.

• When recalled, they always replace the current instrument state immediately.

This instrument state file is saved without any calset data. You might choose to use this type of save file if you are concerned about disk space or specifically do not want to store calibration data that tends to have a shelf life. That is, calibrations become less accurate as cables move and temperature changes. Perhaps you want to force a new calibration when the instrument state is used.

*.cst files

• Contain BOTH instrument state and a LINK to the Cal Sets. Learn more about Cal Sets.

• The quickest and most flexible method of saving and recalling a calibrated instrument state.

• Channels need not have cal data to save as .cst file.

• When recalled, the state information is loaded first. Then the analyzer attempts to apply a Cal Set as you would do manually. If the stimulus settings are different between the instrument state and the linked Cal Set, the usual choice is presented (see Cal Sets). If the linked Cal Set has been deleted, a message is displayed, but the state information remains in place.

• Because only a link to the Cal Set is saved, the Cal Set can be shared with other measurements.

• If you perform a calibration and save the result to a calset called “MyCalSet”, then save  a .cst file (for example, MyState.cst), then that file will have a reference to the name of the calset (“MyCalSet”).  

  • If you redo the calibration and store the data again in MyCalset, then the next time you recall MyState.cst, your instrument state will use the new calibration data.

  • If you subsequently delete MyCalset, and then recall the  MyState.cst, the resulting instrument state will not be calibrated as the calset no longer exists.

Note: Before saving a .cst file, be sure that a User Cal Set (NOT a Cal Register) is being used for the calibration. Cal Registers are overwritten with new data whenever a calibration is performed, and may not be accurate cal data when the .cst file is recalled. Learn more about Cal Sets.

*.cal files

• Contain ONLY Cal Set information.

• When recalled, the Cal Set is NOT automatically applied. Apply the calibration data to a channel as you would apply any Cal Set.

*.csa files

• Contain ALL instrument state and the actual Cal Set; not a link to the Cal Set.

• The safest method of saving and recalling a calibrated instrument state. However, the file size is larger than a *cst file, and the save and recall times are longer.

• Channels need not be calibrated to save as .cst file.

• The Cal Set that is saved could be a Cal Register or a User Cal Set.

A .csa file is an instrument state and a collection of calset data. Every channel that has an active calibration (that is, has a calset selected and applied to the channel) stores its calibration data into the .csa file. For example, let's say you have a calset called “mycalset” and you are using that calset on channel 1. You save a .csa file called MyState. If you then perform another calibration and save that calibration to “mycalset”, the data in “mycalset” will not be the same as the calibration data in the MyState file. Consequently, when you recall MyState the old calset called “mycalset” will overwrite the new calset “mycalset”. When this is about to occur, you are given a warning. If this is  a problem for you, you might prefer to use a .cst file.

Note: *.pcs files are the internal file format used for storing cal sets. These files should never be accessed or copied by the user.

Measurement Data Files

Measurement data is saved as ASCII file types for use in a spreadsheet or CAE programs.

Note: Before saving measurement data, always trigger a single measurement, and then allow the channel to go into Hold.  This ensures that the entire measurement trace is saved.

Note: Memory traces can only be saved in select file types (CTI, CSV, MDF) when the “Scope” data setting is set to “Displayed Traces”.

The following file types can be saved by the analyzer:

• *.prn files

• *.SNP (Touchstone)

• *.cti (Citifile)

• *.csv

• *.mdf (MDIF)

*.prn Files

Prn files have the following attributes:

• Comma-separated data which can be read into rows and columns by spreadsheet software, such as Microsoft Excel. To avoid the "delimiting" dialog boxes, change the filename extension from .prn to .csv. Then open directly into Microsoft Excel.

• Contain formatted and corrected stimulus and response data for the current active trace ONLY.

• Are Output only - they cannot be read by the analyzer.

• Does not save memory traces.

• Cal Set Viewer data can be saved to *.prn files

Example:

.SNP Format (*.s1p, *.s2p, *.s3p. *.s4p, and so forth)

• *.SNP file format, also known as Touchstone format, is specified by IBIS. See the Touchstone specification. The VNA supports Version 1.0 of the Touchstone format.

• *.SNP file format is used by CAE programs such as Keysight's Microwave Design System (MDS) and Advanced Design System (ADS).

• *.SNP data is saved using the File, Save Data As dialog.

Before saving measurement data, always trigger a single measurement, and then allow the channel to go into Hold.  This ensures that the entire measurement trace is saved.

*.SNP files and other analyzer settings

• .SNP data can be recalled and viewed on the analyzer, or read by the embed/de-embed functions.

• To save SNP data with an external test set enabled, at the File, "Save Data As" dialog, select SnP Network File(*.s*p), then complete the "Select Ports for SnP file" dialog.

• When Fixturing is enabled, all of the enabled data transforms (De-embedding, Port Z Conversion, and so forth) are applied to saved SNP files.

• When the Data Type = “Formatted” (Learn more about Data Types):

  • Smoothing is NOT saved when the format is Real, Imaginary (RI). Select a different format to save the smoothed data.

  • Gating is applied on a per-trace basis.

• Segmented FCA data is saved to *.S2PX files. Scroll down or click here to learn more.

• Learn about FCA parameters that are saved to an S2P file.

• Balanced parameters can be saved to *.SNP files. See the "Select Ports for SnP file" dialog.

What is Saved

*.SNP data is generally used to gather all S-parameters for a fully corrected measurement.

The analyzer saves the data that is available on the channel of the active measurement.

• If correction for a Full N-port cal is applied, then valid data is returned for all corrected s-parameters. Response cals will save uncorrected data.

• If correction is NOT applied, the analyzer returns as much applicable raw data as possible using S-parameter measurements on the selected channel. Data that is not available is zero-filled. For example, if correction is NOT applied and the active measurement is S11, and an S21 measurement also exists on the channel, then data is returned for the S11 and S21 measurements. Data for S12 and S22 is not available and therefore returned as zeros in Real/Imaginary format. In Log Mag/Phase format, this appears as -200 dB and 45 degrees. See “Data Type” in Save Data As dialog help.

SNP Data Output

.SNP files contain header information, stimulus data, a response data pair for EACH S-parameter measurement. The only difference between .s1p, s2p, and so forth, is the number of S-parameters that are saved.

The following is a sample of Header information:

!Keysight Technologies,E8362B,US42340026,Q.03.54

!Keysight E8362B: Q.03.54

!Date: Friday, April 25, 2003 13:46:41

!Correction: S11(Full 2 Port SOLT,1,2) S21(Full 2 Port SOLT,1,2) S12(Full 2 Port SOLT,1,2) S22(Full 2 Port SOLT,1,2)

!S2P File: Measurements:S11,S21,S12,S22:  

# Hz  S RI R 50

Note: Although the following shows Real / Imag pairs, the format could also be LogMag / Phase or LinMag / Phase

*.s1p Files

Each record contains 1 stimulus value and 1 S-parameter (total of 3 values)

Stim  Real (Sxx)  Imag(Sxx)

Example:

*.s2p Files

Each record contains 1 stimulus value and 4 S-parameters (total of 9 values)

Stim  Real (S11)  Imag(S11)  Real(S21)  Imag(S21)  Real(S12)  Imag(S12)  Real(S22)  Imag(S22)

Example:

*.s3p Files

Each record contains 1 stimulus value and 9 S-parameters (total of 19 values)

Stim   Real (S11)  Imag(S11)  Real(S12)  Imag(S12)  Real(S13)  Imag(S13)

          Real (S21)  Imag(S21)  Real(S22)  Imag(S22)  Real(S23)  Imag(S23)

          Real (S31)  Imag(S31)  Real(S32)  Imag(S32)  Real(S33)  Imag(S33)

Example:

*.s4p Files (and so forth...)

Each record contains 1 stimulus value and 16 S-parameters (total of 33 values)

Stim   Real (S11)  Imag(S11)  Real(S12)  Imag(S12)  Real(S13)  Imag(S13)  Real(S14)  Imag(S14)

          Real (S21)  Imag(S21)  Real(S22)  Imag(S22)  Real(S23)  Imag(S23)  Real(S24)  Imag(S24)

          Real (S31)  Imag(S31)  Real(S32)  Imag(S32)  Real(S33)  Imag(S33)  Real(S34)  Imag(S34)

          Real (S41)  Imag(S41)  Real(S42)  Imag(S42)  Real(S43)  Imag(S43)  Real(S44)  Imag(S44)

Example:

.S2PX Data Output

*.S2PX files are used for Segmented Mixer Data. Learn more.

The following ADDITIONAL columns precede parameter data:

SegIndex,InputFreq,OutputFreq,LO1Freq,InputPower,LO1Power, <parameter data>

.cti CitiFiles

Citifile format is compatible with the Keysight 8510 Network Analyzer and Keysight's Microwave Design System (MDS).

You can do the following using citifiles :

• save the active trace, or all traces.

*.cti files contain:

• Header information

• Stimulus data

• Data pairs for EACH S-parameter measurement

*.csv Files

CSV files are read by spreadsheet programs such as Microsoft Excel.

*.csv files contain: header information and the following Comma-Separated Values.

• Stimulus data

• Data pairs for EACH S-parameter

*.mdf Files

MDIF files are compatible with Keysight ADS (Advanced Design System). Learn more at the Keysight website.

*.mdf files contain: header information and space-separated data:

1. • Stimulus data

   • Real and Imaginary data pair for EACH S-parameter measurement

Manage Files without a Mouse