Conducted interference is a component of EMI testing, which tests the interference signals generated by EUT during operation. These signals can affect the normal operation of other devices through power or signal lines. To conduct a conducted interference test, the necessary equipment includes a testing site - shielded room, receiver, coaxial cable, etc LISN， There are currently two LISNs in the laboratory. LISN8127 is mainly used for single EUT testing, while LISN8128 is mainly used for testing EUT with 3-phase power supply.

Ordinary products are divided into three categories:

One type is information technology and audio and video, using the standard EN55032;

The second category is household appliances, and the standard used is EN55014;

The third category is lighting fixtures, and the standard used is EN55015;

The four categories are audio and video.

According to the standard regulations, the distance between EUT and LISN is 1 meter, and the distance from the vertical ground plane, that is, the vertical wall of the shielding room, is 0.4 meters. Desktop equipment is placed on an insulated table of 0.8 meters, and the floor standing equipment room is placed on an insulated wooden board of 0.15 meters. Depending on the product category, the testing frequency and limit may vary. The testing frequency for lighting fixtures is from 9KHZ-30MHz, while the testing frequency for other ordinary products is from 150KHZ-30MHz. The conducted disturbance testing site includes the following testing ports: 1. Power port, testing method: Use LISN for measurement. 2. Load port/control port, testing method: Use a voltage probe for measurement, mainly in EN55014-1 and EN55015. 3. Communication port, testing method: Use ISN for measurement.