A coupling decoupling network (CDN) allows users to perform conducted immunity testing. The CDN, when paired with a generator, will start by injecting a common mode disturbance into the Equipment Under Test (EUT). Through a series of cables and series conductors, the coupling network delivers a specific disturbance signal to the EUT.
Most electrical equipment will also interact in some way with other devices, or auxiliary equipment (AE). The decoupling network guarantees that a disturbance signal from the generator doesn't affect the auxiliary equipment. CDNs are preferred in immunity testing not just for reproducibility, but safety for all equipment besides the EUT. Even under repeated testing, a coupling decoupling network ensures safety for the AE.
While all CDNs will perform similar functions, the signals they produce and test for will differ. Some coupling decoupling networks will perform EMC immunity tests for an RF sweep. Others will test for transients, including EFT/Burst, Surge, and similar waveforms. It's crucial to choose the right CDN for your immunity testing needs to meet IEC/EN standards.
A transient CDN is specifically made for EFT/Burst disturbances and currents with a pulse shape. The coupling decoupling network will inject quick surges into the EUT, often devices with higher voltages and currents. A different device, an RF CDN, is needed when immunity testing for disturbances from conducted radio frequency waves. Both transient and RF coupling decoupling networks test the EUT for these ANSI/IEEE
and EN standards