Conducted Emission Testing

Conducted RF emissions are electromagnetic voltages (or currents) generated by electrical and electronic operation of a device. When measuring conducted emissions on a power line the standard is restricting the amount of electromagnetic energy a device generates and puts it on the electrical supply / grid.

To minimize the amount of interference that a device can couple back into a power supply, test laboratories calculate these emissions (typically between 150 kHz and 30 MHz) and check that they are below defined limits.
This serves to ensure that the local electricity source is reasonably ‘clean,’ and that the system has little effect on surrounding devices.

Maximization is a measurement technique used to determine the maximum amplitude of the product’s emissions. Once we’ve identified the frequencies with the highest emission, we’ll run a maximization process. All testing is performed in a 10m EMC chamber.

The frequency range 150 kHz to 30 MHz is a very general frequency range used for most conducted emissions standards. However, in specific circumstances, this range could change.

Since various specifications require different frequency ranges and impedances, LISN suppliers usually have a line of goods that meet all of these criteria.

A LISN is a low-pass filter that is usually mounted between an alternating current or direct current power source and the DUT (Device Under Test). It has a very specific known impedance and an RF noise measuring port that connects to a measuring receiver or spectrum analyzer.

The frequency range 150 kHz to 30 MHz is a very general frequency range used for most conducted emissions standards. However, in specific circumstances, this range could change.
Since various specifications require different frequency ranges and impedances, LISN suppliers usually have a line of goods that meet all of these criteria.