Conducted Immunity : Inconsistencies in power measurements
Posted: 25 Jun 2024, 16:32
I have an issue with the Conducted Immunity, specifically regarding my power measurements during test.
I have set up my test site with a CWS500N1, it has signal generator, amplifier and a power meter.
I have made a system calibration for this test. I am using a CDN (Luthi 801 M216) and have put a 150Ω on one side and a 100Ω on the other, going into the monitoring input of the CWS with a cable ending in a 40dB attenuator (protection for the internal power meter).
I have indeed set it up as a cable with a correction file for 40 dB in the test setup (I'm not including it as my screenshot is limited.)
Here is a handcrafted schematic.
Here is the set-up page.
Using this calibration I’ve tried testing using Substitution test and Multiband test and I’m finding different values in power for the same 10V test level. Real test using an EUT.
In addition, I’m finding different values when I set up the test using Signal Power calibration, when in my mind I should have the same values ?
Here are my tests setups:
Set up for Forward power, Ive tried with Signal power
Here are tables from beginnings of tests:
Multiband using forward power || Substitution using forward power
Multiband using signal power || Substitution using signal power
Second test shows 32 dB on the CWS
Forward power on the CWS screen gives me 33 dB here
I am not sure how or where I’m going wrong here. I think I should have the same values regardless of basing the test on Signal or Forward power. 10V is the same level so…. ?
What am I missing here ?
Help would be greatly appreciated, thank you.
I have set up my test site with a CWS500N1, it has signal generator, amplifier and a power meter.
- Test-Site1.png (92.01 KiB) Viewed 25966 times
- Test-Site2.png (78.57 KiB) Viewed 25966 times
I have made a system calibration for this test. I am using a CDN (Luthi 801 M216) and have put a 150Ω on one side and a 100Ω on the other, going into the monitoring input of the CWS with a cable ending in a 40dB attenuator (protection for the internal power meter).
I have indeed set it up as a cable with a correction file for 40 dB in the test setup (I'm not including it as my screenshot is limited.)
Here is a handcrafted schematic.
- Schematic_calibration.png (31.95 KiB) Viewed 25966 times
Here is the set-up page.
- Calibration_Forward.png (93.38 KiB) Viewed 25966 times
Using this calibration I’ve tried testing using Substitution test and Multiband test and I’m finding different values in power for the same 10V test level. Real test using an EUT.
In addition, I’m finding different values when I set up the test using Signal Power calibration, when in my mind I should have the same values ?
Here are my tests setups:
- multi-setting.png (160.24 KiB) Viewed 25966 times
- Substitution-setting.png (178.73 KiB) Viewed 25966 times
Set up for Forward power, Ive tried with Signal power
Here are tables from beginnings of tests:
Multiband using forward power || Substitution using forward power
- Multi_Forward.png (167.01 KiB) Viewed 25966 times
- Subs_Forward.png (162.87 KiB) Viewed 25966 times
Multiband using signal power || Substitution using signal power
- Multi_Signal.png (178.14 KiB) Viewed 25966 times
- Subs_Signal.png (146.55 KiB) Viewed 25966 times
Forward power on the CWS screen gives me 33 dB here
I am not sure how or where I’m going wrong here. I think I should have the same values regardless of basing the test on Signal or Forward power. 10V is the same level so…. ?
What am I missing here ?
Help would be greatly appreciated, thank you.