EMI measuring instrument

Electromagnetic compatibility( EMC) is not a directly measurable quantity. It is verified by measuring the interference emission and immunity level. Here, it is important that the electromagnetic environment prevailing when the DUT is used is well simulated.

EMC measurement technology is divided into the following disciplines:

• Susceptibility measurement technology (measurement of the immunity to interference)
• Emission measurement technique (measurement of interference emission)
• Measurement of interference suppression, e.g. shielding attenuation

Since EMC measurement technology involves measuring both small and large electrical quantities over a wide frequency range, it places high demands on EMC measurement equipment. The measurement of electromagnetic influences, such as interference voltages, interference currents or interference powers is carried out with suitable sensors or measuring transducers (probes, current transformers, antennas) and results in an evaluable voltage signal.

Instruments used to measure the above EMC quantities include gaussmeters, teslameters, radiation meters, E- field probes, noise receivers, spectrum analyzers, network analyzers, oscilloscopes, and other measuring devices.

Sniffer probes: Sniffer probes are used to detect spatially limited electric or magnetic fields. They detect electric fields according to the principle of charge displacement in a capacitance as a function of field strength. Magnetic fields are detected according to the induction principle using small coils.

EMC antennas are used to measure the field strength of interfering radiation and to generate defined electromagnetic fields. EMC antennas are logarithmic, periodic broadband antennas for use in mobile communications(GMS, UMTS) WLAN, radar, microwave, building biology and other areas.