The purpose of the test is to verify the ability of the device under test to function correctly in the presence of RF disturbances (electromagnetic field with frequency sweep and AM modulation) injected into the power conductors and signal conductors. The test aims to ensure the proper operation of equipment in the presence of radio transmitters, in case the disturbing field couples with the power or signal conductors of the device under test.
The test is performed using a test generator and a coupling device; the test generator includes the RF signal generator, the wideband power amplifier, and an attenuator to reduce decoupling between the power amplifier and the coupling network. The coupling and decoupling device can be combined in a single container (CDN) or be made in multiple parts. Its main parameter is the common mode impedance seen at the EUT port (typically 150Ω). The type of coupling device to be used depends on the type of cable to which the disturbance is to be coupled. The RF signal, produced by a signal generator and appropriately amplified by a power amplifier, is injected into the lines to be tested in common mode, simultaneously on all lines to be tested with respect to the ground plane. The RF signal is varied scanning the frequency range from 150 kHz to 80 MHz (unless otherwise specified, but it can reach up to 230 MHz) with the amplitude modulated at 80% with a 1 kHz sine wave, the step amplitude should not exceed 1% of the fundamental with linear interpolation of the calibrated points. The RF signal level is automatically adjusted at each frequency so that the voltage amplitude is constant at the injection point.
The test is performed using a test generator and a coupling device; the test generator includes the RF signal generator, the wideband power amplifier, and an attenuator to reduce decoupling between the power amplifier and the coupling network. The coupling and decoupling device can be combined in a single container (CDN) or be made in multiple parts. Its main parameter is the common mode impedance seen at the EUT port (typically 150Ω). The type of coupling device to be used depends on the type of cable to which the disturbance is to be coupled. The RF signal, produced by a signal generator and appropriately amplified by a power amplifier, is injected into the lines to be tested in common mode, simultaneously on all lines to be tested with respect to the ground plane. The RF signal is varied scanning the frequency range from 150 kHz to 80 MHz (unless otherwise specified, but it can reach up to 230 MHz) with the amplitude modulated at 80% with a 1 kHz sine wave, the step amplitude should not exceed 1% of the fundamental with linear interpolation of the calibrated points. The RF signal level is automatically adjusted at each frequency so that the voltage amplitude is constant at the injection point.The standard EN 61000-4-6
Electromagnetic Compatibility (EMC) - Part 4: Testing and Measurement Techniques. Section 6: Immunity to conducted disturbances, induced by radio-frequency fields” defines the test methodology and the characteristics of the set-up and test equipment including coupling networks or devices. Technical product committees then identify in specific product standards the severity levels in terms of voltage level in V, frequency range, and type of modulation to be applied for the specific type of product or product family.
Example of test principle diagram:
