Immunity to conducted disturbances induced by RF fields - 150 kHz–80 MHz, levels 1–10 V.
The standard specifies conducted-immunity requirements for equipment exposed to disturbances originating from intentional radio-frequency transmitters in the range 150 kHz to 80 MHz. In this range the wavelength is large compared with equipment dimensions, so the radio field couples to cables (power, signal and earth lines) and reaches the equipment as a common-mode voltage.
The standard applies to equipment having at least one conductor or cable capable of such coupling; equipment without such connections is excluded.
The test demonstrates that equipment withstands a specified common-mode voltage injected into its cables over the RF range without losing the specified function. The method number is not a declaration of conformity; voltage level, tested ports and performance criterion are selected by the product or generic EMC standard.
Cable systems are represented by coupling/decoupling devices with a common-mode impedance of 150 Ω. The disturbance is injected by one of three methods: through a coupling/decoupling network (CDN, preferred), through a clamp (current or electromagnetic clamp), or by direct injection through a 100 Ω resistor.
The RF signal is amplitude-modulated with a 1 kHz sine wave at 80% depth. Frequency is swept in steps not exceeding 1% of the preceding value, with dwell time no shorter than the equipment response time and at least 0.5 s. Results are assessed in four categories from normal operation through temporary loss with automatic recovery and loss requiring operator intervention to irreversible loss of function.
Ed. 5.0 changed selection of injection devices, removed the AE impedance check for the clamp, changed the saturation-check procedure, added Annex H on multi-signal testing and restricted level setting to the feedback-loop method.
Check test voltage (V) and the performance criterion for power and signal ports; 10 V corresponds to level 3. EN 50121-3-2:2016 references this method with a requirement of 10 V, 0.15–80 MHz, AM 80% (1 kHz), criterion A for power and signal ports.
