Talk:RadiMation Application Note 104
Isn't the performing of a current sensor calibration, not simply performing a cable calibration using the attenuation/gain calibration module? The determined attenuation is a little bit higher than a standard cable, but the principle is the same.
Joro 09:13, 6 October 2015 (UTC)
Another idea: What does Google say on: "how to calibrate RF Current sensor"?
Joro 09:14, 6 October 2015 (UTC)
See: http://fischercc.com/productfiles/Current_Probe_Calibration_Rev_A_001c.pdf It is a very good description on how the current sensor can be calibrated. In RadiMation this is a cable attenuation test. Then the result is a positive cable loss. The sign of that cable loss should be inverted (-), and +34 dB should be added. This results in a dBOhm transfer impedance, which can be specified in the 'Resistance' column in a Correction file.
As a verification a Fixed signal power test at 0 dBm can be performed, while the current is also measured with the current sensor and the sensor powermeter. The measured current should be 4.4 mA. Psg == 0 dBm = I*I * R. I = sqrt(P/R) = sqrt( 1 mW / 50) = 4.4 mA.
Sast 12:51, 6 October 2015 (UTC)
The link to the fishercc.com document is not present anymore. Probably we can still find it, but we have to search it again. JORO should determine the correct procedure on how to do this current sensor calibration. Based on that we can explain how to do it with RadiMation. The correct link to Fischer CC document is: https://www.fischercc.com/wp-content/uploads/2016/07/Current_Probe_Calibration_PGD_2014_02_06_2.pdf
Another good page is: https://design-4-emc.com/2013/01/22/question-on-current-probe-calibrations/
The good procedure is probably:
- use a signal generator and powermeter (preferrable a powermeter driver that is using a spectrum analyzer)
- perform an attenuation/gain system calibration
- Attach the signal generator to the calibration jig
- position the current sensor in the calibration jig
- Attach the powermeter to the current sensor => Include a schematic drawing.
- Perform the attenuation/gain EUT calibration
- The result is the dB loss for the current sensor, however it should be converted to dB Ohm.
- Show the formula to perform the conversion => Convert the sign and Add 34 dB to get dBOhm
- Export the attenuation to excel, add 34 and paste back into correction file, which uses dBOhm resistance unit.
- Connect the correction file to the current sensor
Validation can be performed by doing with same setup a 0 dBm signal power test, and measure the current. The expected current should be: 4.4 mA (See formula's of SAST above).
The application note should also include the formula's to explain the idea...
We can also include the relevant links and references in a section on the bottom.
Joro (talk) 10:04, 29 January 2019 (CET)
For the validation an additional powermeter is needed, to ensure that the correct power is generated in the calibration jig. Just generating a fixed signal power level is not suitable, as the attenuator is still present, and it could have a frequency curve....
Joro (talk) 16:25, 29 January 2019 (CET)
Name of the application note[edit]
The title of the application note states that the calibration should be done using the conducted immunity fixed power method. However we are now suggesting to use the attenuation/gain calibration. Which one is better??? fixed power disadvantage:
- Have to correct for the power meter => 2 tests..
- Have to explain that the power reading should be using a coupler
- Forward power is not forward power... but sensor power
- Power reading should be converted to loss and then add more formula's
=> It is better to use the attenuation gain, so we will use that method, and then we thus also should adjust the title of the application. Better name: How to determine the current sensor transfer impedance
Joro (talk) 11:17, 29 January 2019 (CET)
Minimum number of changes between System and EUT calibration[edit]
It probably is even better to also have the current sensor mounted in the calibration jig during the system calibration. Not because it is necessary for the system calibration, but that it is even more closely to the situation of the EUT calibration. For the same reason it probably is also better to have the 50 Ω load present on the current sensor during the system Calibration, so all the impedances during the system calibration are as similar as possible as during the EUT calibration.
Review Status[edit]
JORO: Not yet reviewed. Joro (talk) 13:17, 31 January 2019 (CET)
Possible duplicated page[edit]
Also see the page: Current sensor transfer impedance determination method. It seems to describe the same method. It probably is better to merge the information from Current sensor transfer impedance determination method into this page, and redirect the other page to RadiMation Application Note 104.