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PicoVNA5 SDK S21 Parameters
PicoVNA5 SDK S21 Parameters
Hello, I am trying to control PicoVNA108 over python using pico5sdk. I want to measure only s21 parameters. While I was using Pico3 software I was able to load only thru calibration file and I could measure only s21s.
However, if I try to load only thru cal file python script crashes with "Process finished with exit code -1073740791 (0xC0000409)" this error. I can only load SOLT calx files via python. Is there any options to measure only s21s?
However, if I try to load only thru cal file python script crashes with "Process finished with exit code -1073740791 (0xC0000409)" this error. I can only load SOLT calx files via python. Is there any options to measure only s21s?
Re: PicoVNA5 SDK S21 Parameters
Hello,
The S21-only correction method has not been implemented in PicoVNA 5 because it is only a simple correction based on normalisation that can be easily implemented in user code.
To implement an S21-only correction:
1. Load the factory calibration
2. Measure a zero-length through
3. Record the measurements
4. Measure the DUT
5. At each frequency, divide the DUT's S-parameters by the measurement at the same frequency for the zero-length through. Note that a complex division must be used.
The S21-only correction method has not been implemented in PicoVNA 5 because it is only a simple correction based on normalisation that can be easily implemented in user code.
To implement an S21-only correction:
1. Load the factory calibration
2. Measure a zero-length through
3. Record the measurements
4. Measure the DUT
5. At each frequency, divide the DUT's S-parameters by the measurement at the same frequency for the zero-length through. Note that a complex division must be used.
Re: PicoVNA5 SDK S21 Parameters
Hi, thank you but that is not the main problem here. I want only to measure s21 parameters, to do that I was loading thru cal. If there is any control for choosing the measurement parameters that would also work too.
In the default case, if I load SOLT calibration it measures all s parameters.
In the default case, if I load SOLT calibration it measures all s parameters.
Re: PicoVNA5 SDK S21 Parameters
Hi,
It would be good to understand what the underlying reason for only wanting to measure S21 is:
1. Is the reason for only wanting S21 for faster measurement speed?
2. Is the reason for only wanting S21 so that no stimulus is applied to Port 2 of the DUT?
In terms of measurement, the PicoVNA 108 instrument supports two modes:
1. Measure S11+S21+S12+S22 (default for SOLT and SOLU calibrations)
2. Measure S11+S21 (default for S11-only calibrations)
In VNA3, when an S21 calibration was loaded, the instrument measured both S11 and S21, but discarded S11 in software.
In VNA5, the same could be achieved by loading an S11+S21 calibration and discarding the S11 measurements. (The S11+S21 calibration type is only available via the UI software and SCPI currently, and will be released for the Python API soon.)
It would be good to understand what the underlying reason for only wanting to measure S21 is:
1. Is the reason for only wanting S21 for faster measurement speed?
2. Is the reason for only wanting S21 so that no stimulus is applied to Port 2 of the DUT?
In terms of measurement, the PicoVNA 108 instrument supports two modes:
1. Measure S11+S21+S12+S22 (default for SOLT and SOLU calibrations)
2. Measure S11+S21 (default for S11-only calibrations)
In VNA3, when an S21 calibration was loaded, the instrument measured both S11 and S21, but discarded S11 in software.
In VNA5, the same could be achieved by loading an S11+S21 calibration and discarding the S11 measurements. (The S11+S21 calibration type is only available via the UI software and SCPI currently, and will be released for the Python API soon.)
Re: PicoVNA5 SDK S21 Parameters
Both of your assumptions on the reasons are valid for our case. I only want to measure s21s in the system and it must be fast as possible