The module NetworkAnalyzuer is used to retrieve S-parameters from PNA or VNA instruments. At each measurement point created in the sequencer, a full frequency scan of S-parameters is returned by the driver. The module is not part of the standard installation of SweepMe! and can be downloaded if needed using the Version manager.
Select the driver.
Select the communication port. Use 'Find ports' to refresh the list of ports.
Select the calibration. Use 'Find calibrations' to refresh the list of calibrations. Which calibrations are presented depends on the driver and you can find further details in the description of the driver. In general, all calibration files must be saved to the public SweepMe! folder "CalibrationFiles".
Select the measurement ports that are connected to the device under test, e.g. "1,2" to retrieve S11, S12, S21, and S22. You can also use "1,3,4" to retrieve all 9 S-parameters between these ports or "1,2,3,4" to get all 16 S-parameters. If your instrument only has two ports, you can only use "1,2" or one of the two ports.
Optionally, enter individual S-parameters, e.g. "S13, S31" if you don't want to measure all S-parameters as otherwise created by the selection of the terminals. The numbers in the field "Terminals" will have no effect on the measured S-paraemter but could still be needed, depending on the driver, to set terminal properties.
Insert over how many numbers the measurement should be averaged.
Select the source power in dbm. This value is applied to all ports.
Select the source attenuation in dB. This value is applied to all ports.
Select the IF bandwithh in Hz
Switch the correction on or off.
Select whether an internal or external trigger is used and whether a trigger delay should be used.
Define the list of frequency. Insert a start and end freuqency. Depending on the driver you can have different options to create linearly or logarithmicly spaced frequencies. For compatibility between all drivers, the options should be "Linear (points)", "Linear (steps in Hz)", and "Logarithmic (points)".
Select whether the display is updated or not. This can increase the measurement speed as no plots are updated if the display is switched off.
Touchstone format export
When selecting the touchstone export, the module will automatically save the measured data in .sNp data files where N is the number of ports involved. The export is done using the library scikit-rf with the following modifications:
- The versions of SweepMe! and scikit-rf are added to the header of the file
- The date and time is added to the header
- The values of several parameters are added to the header
- The labels of the S-parameters are replaced with the ones that have been used during the measurment. Normally, the S-parameters have the name S11, S21, S12, S22 independent from the physical ports that have been used. Now, if one is doing a 2-port measurement between port 2 and 4, the S-parameters in the file are called S22, S42, S24, S44. When reading in the touchstone file, the most software tools will still identify the values as S11, S21, S12, S22 but the labels of the S-parameters in the header of the file allow to see the originally used ports.
- If a user only measures a fraction of all possible S-parameters, the touchstone file will automatically expanded to the lowest dimension that still covers all measured S-parameters. All missing S-parameters will be filled with zeros and the labeled with None. For example, if one measures S24 and S42 of ports 2 and 4, a .s2p file will be generated where the S22 and S44 positions will be filled with zeros and labeled with None, while the measured S-parameters are at the positions in the file that are related to S12 and S21 of a 2-port network.