FAQ/Immunity

This page contains all kind of Frequently Asked Questions related to RadiMation^®

RadiMation^® FAQ: General | Immunity | Emission | Report Generator

Does RadiMation support the linearity check that is described in the EN 61000-4-3 standard?

In RadiMation^® it is fairly easy to verify that the amplifier is used in its linear range (and thus not saturated).

The EN 61000-4-3 2006 version specifies that the calibrations in the Uniform Field Area should be performed on electrical field strength that is at least 1.8 times higher than the field strength that will be used during the substitution test. It is also required that it is ensured that the amplifier is used in a range in which it is not in saturation. To be able to perform a substitution test on 10 V/m, it is thus necessary that the calibrations are performed on at least 18 V/m. The Uniform Field Area calculation can be performed as it is described in Chapter 12. After the the complete calculation has been performed, and a final calibration file has been created, it has to be ensured that the amplifier will not be used in saturation.

The easiest way to confirm that the amplifier is not used in saturation, is:

1. Configure a Radiated Immunity substitution test with the calibration file that was the result of the Uniform Field Area calculation. Ensure that the substitution test is configured with the correct settings:
   • use the signal generator calibration method.
   • the forward power input should be activated, because the forward power should be measured.
   • level to an electrical field strength that is exactly 1.8 times lower than the field strength that was calibrated. This will result in a 5.1 dB lower signal generator power.
   • use the same frequency range and frequency steps, as was used during the calibration.
   • use the same testsite as was used during the calibration.
2. Start the substitution test and wait until it is finished.
3. Now the forward power that is used during the substitution test, and the forward power during the calibration should be compared. It is the most easiest to do this in Microsoft Excel. Start Microsoft Excel, and create an empty sheet.
4. Open the calibration file that was the result of the Uniform Field Area calculation.
5. Open the forward power graph, and copy the data (table) of the forward power to the clipboard.
6. Paste the forward power of the calibration file into the Microsoft Excel worksheet (for example on cell A6)
7. Open the results of the substitution test, open the forward power graph, and copy the data (table) of the forward power to the clipboard.
8. Paste the forward power of the substitution test into the Microsoft Excel worksheet (for example on cell D6)
9. Compare the data of the forward power of the calibration and the forward power during the substitution. The forward power of the substitution should be 5.1 dB lower then the forward power of the calibration file. The comparison is very easy, by inserting the formula '=B6-E6' in cell H6. The formula can then be copied down for all other frequencies.
10. The EN 61000-4-3 standard assumes that the amplifier is not in saturation if the difference between the forward power values on all frequencies is within +3.1 dB to +5.1 dB.

An example Microsoft Excel file, can be downloaded here, which can be used for the calculations.

Another possibility to ensure that the amplifier is not used in saturation, is to limit the generated power of the amplifier to its 1 or 2 dB compression point. The amplifier limitation feature of RadiMation^® can be used to limit the generated power of the amplifier.

Why are the Uniform Field Area calculations of expired standards not removed?

The calculation methods for the old standards (like EN 61000-4-3:1995) cannot be removed from RadiMation^® due to the following reasons:

1. A number of product standards do mention basic standards and there year of issue, for the way of performing radiated immunity tests. As long as the product standards are not changed one should use the 'old' basic standard as well. Although many lab's do use the latest version of the basic standard for all product standards (while it is much more convenient to use only one version of the EN61000-4-3), when there is doubt about the test results, one should use the harmonized standard and it's associated basic standard as mentioned in the product standard.
2. A number of customers simply require the old methods, for the reasons mentioned above, or while they want to be able to perform verification tests on old products

Is RadiMation^® using the correct method for the Uniform Field Area calibration?

The latest EN 61000-4-3 standard describes two methods to perform a "field homogeneity verification" (also called 'Uniform Field Area calculation') (the constant field method and constant power method). RadiMation^® supports the constant field method while this will result in the highest accuracy (With this procedure, the linearity error of the field probe is not influencing the calibration accuracy. While the linearity of a power meter is much better than the linearity of a field probe, this method is, from an accuracy point of view, the better solution). Although RadiMation^® does not support both methods, this does not mean RadiMation^® can not be used for field homogeneity verification, because according to the standard, both methods should result in the same calibration file.

Why is an immunity test trying to control a field sensor, if no field sensor is selected in the used testsite?

RadiMation^® does not automatically disable a setting in a TSF file, if certain equipment is not selected in the selected testsite.

It can be possible that measurements procedures require that a field sensor is used during an immunity measurement. The fieldsensor is then activated in the Fieldsensor Inputs window of the TSF file. If however, due to circumstances the fieldsensor is not available in a certain situation, it is unacceptable that RadiMation^® silently decides to not use the activated fieldsensor. The TSF that defines the exact measurement procedure should not be silently modified, because this can lead to unexpected results in future measurements. It is of course allowed that the test engineer modifies the TSF to disable the usage of the field sensor during a specific measurement, but in that case it is a thoughtful action by and the responsibility of the test engineer. RadiMation^® does not silently perform adjustments to the configuration in a TSF file.