CISPR 25 covers a frequency range of 150 kHz to 2.5 GHz and determines the necessary space needed for testing. This standard was developed in response to the variety of radio receivers that can be installed or used in motor vehicles and deals with "radio disturbance characteristics for the protection of receivers used on-board vehicles, boats, and on devices". CISPR 25 is mostly used by vehicle manufacturers to ensure the performance of receivers mounted on the vehicle is top-notch. There are two parts to CISPR 25, full vehicle and components. The full vehicle or system test part uses mounted antennas to sense noise generated by different electronic systems on the same vehicle, where the other part deals with the conducted and radiated measurements of the vehicle's components and modules. The goal of CISPR 25 is to protect the receivers installed in the vehicle from disturbances created by other components or modules within the same vehicle.
A LISN (line impedance stabilization network) is used to provide an impedance to the power input of the EUT. This is an essential tool for when operators need to stabilize power lines so they can perform conducted emissions measurements. There are three main functions of LISNs, as a way to divert unwanted signals from a power source, an RF noise measurement port, and resistance of an electric circuit or component to an alternating current (impedance).