ABSTRACT
Electromagnetic interference affects systems in various ways. Depending upon the severity of the EM threat and the sensitivity of the system, it may lead to an upset or even damage. The behavior of a system may be altered by various degrees and still be acceptable to the user. A burst of interference may cause a momentary malfunction, with the system returning to normal operation within a few milliseconds. However, in safetycritical or in mission-critical systems, such as those found in many military or mobile applications, such a momentary malfunction may have catastrophic results and cannot be tolerated. Another type of upset is that causing a change in the system (such as overwriting parts of a computer memory), which is not immediately detrimental but can cause problems in the future if the problem is not detected and rectified. Finally, interference can cause an irreversible change to the system, such as semiconductor damage, which renders the system incapable of functioning. The degree of upset and the amount of damage that can be tolerated is system dependent and no general advice can be given. However, it is of value to give some guidelines as to how devices fail so that the designer has some grasp of the issues involved.
