Electromagnetic compatibility is a machine’s ability to function in an electromagnetic environment without creating interference. In a simple example, if a computer monitor develops wavy lines when the phone rings, it is likely not compatible, because it is not functioning normally as a result of the operation of another piece of equipment. Likewise, if the monitor creates static on the radio, it is generating interference and is not exhibiting electromagnetic compatibility. This topic is a subject of much interest and concern, as it involves systems that utilize electricity for functions ranging from keeping patients alive to placing phone calls.
Research into the subject of electromagnetic compatibility demonstrates that in some situations, a system can become a source of interference, which may travel along a coupling path to a victim. Electrical systems may create interference for a variety of reasons, and it could travel along paths like wireless signals generated by other equipment or common grounds. Designers of equipment that utilizes electricity, from controllers in a power plant to cell phones, need to be able to make them compliant with hypothetical working environments.
Many nations have electromagnetic compatibility regulations. These mandate that companies design systems within specific parameters to limit the risk of interference. In some cases, before products can be sold, they need to be tested and approved to indicate that they are considered generally safe. Certification markers can be seen on devices like cell phones, televisions, and toasters.
Controlling systems to make sure they adhere to electromagnetic compatibility requirements can be challenging. Some devices, for example, need to transmit signals as part of their function, which can generate interference or create a path for interference. Devices like mobile phones, wireless routers, and baby monitors all need to transmit within specific bands to avoid interfering with other equipment. This prevents situations like people picking up phone conversations on the baby monitor.
Shielding can be used with many systems to limit interference. It can prevent the unwanted release of electromagnetic energy, and also protects devices from outside sources of energy. This can be especially important with extremely sensitive equipment that might be subject to damage as a result of interference. Likewise, systems such as pacemakers need to be compatible to protect the health and safety of patients. If there is a known compatibility issue in a building or area, warning signs may advise people to use caution before entering if they use implanted medical devices.