CISPR 25 controls the radio environment within the vehicle and was developed in response to the variety of radio receivers that can be installed and/or used in modern motor vehicles. The standard subcommittee holds the view that interference to on-board radio reception caused by equipment on the same vehicle is a quality, or customer satisfaction issue, rather than a matter for government regulation.
CISPR 25 defines test methods for use by vehicle manufacturers and suppliers, to assist in the design of vehicles and components and ensure controlled levels of on-board radio frequency emissions.
Vehicle test limits are provided for guidance and are based on a typical radio receiver using the antenna provided as part of the vehicle, or a test antenna if a unique antenna is not specified. The frequency bands that are defined do not apply to all regions or countries of the world. For economic reasons, the vehicle manufacturer must be free to identify what frequency bands are applicable in the countries in which a vehicle will be marketed and which radio services are likely to be used in that vehicle.
CISPR 25 standard accomplishes the following:
- Establishes a test method for measuring the electromagnetic emissions from the electrical system of a vehicle;
- Sets limits for the electromagnetic emissions from the electrical system of a vehicle;
- Establishes a test method for testing on-board components and modules independent from the vehicle;
- Sets limits for electromagnetic emissions from components to prevent objectionable disturbance to on-board receivers
CISPR 25 contains limits and procedures for the measurement of radio disturbances in the frequency range of 150 kHz to 2500 MHz. The standard applies to any electronic/electrical component intended for use in vehicles, trailers, and devices. Refer to International Telecommunications Union (ITU) publications for details of frequency allocations. The limits are intended to provide protection for receivers installed in a vehicle from disturbances produced by components/modules in the same vehicle. The method and limits for a complete vehicle (whether connected to the power mains for charging purposes or not) are in Clause 5 and the methods and limits for components/modules are in Clause 6.
Only a complete vehicle test can be used to determine the component compatibility with respect to a vehicle's limit. The receiver types to be protected are, for example, broadcast receivers (sound and television), land mobile radio, radiotelephone, amateur, citizens' radio, Satellite Navigation (GPS, etc.), Wi-Fi and Bluetooth. For the purpose of this standard, a vehicle is a machine, which is self-propelled by an internal combustion engine, electric means, or both. Vehicles include (but are not limited to) passenger cars, trucks, agricultural tractors, and snowmobiles. Annex A provides guidance in determining whether this standard is applicable to particular equipment. This fourth edition cancels and replaces the third edition published in 2008.
This edition of the CISPR 25 constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - inclusion of charging mode for electric vehicles (EV) and plug-in electric vehicles (PHEV), - the methods for chamber validation have been included, - test methods for shielded power supply systems for high voltages for electric and hybrid electric vehicles have been included, - overall improvement.