The furniture near field cable to cable coupling in emi pdf to be made of wood or plastic, not metal. The goal of EMC is the correct operation of different equipment in a common electromagnetic environment. EMC pursues three main classes of issue. Emission is the generation of electromagnetic energy, whether deliberate or accidental, by some source and its release into the environment.
EMC studies the unwanted emissions and the countermeasures which may be taken in order to reduce unwanted emissions. Immunity is the opposite of susceptibility, being the ability of equipment to function correctly in the presence of RFI, with the discipline of “hardening” equipment being known equally as susceptibility or immunity. A third class studied is coupling, which is the mechanism by which emitted interference reaches the victim. Interference mitigation and hence electromagnetic compatibility may be achieved by addressing any or all of these issues, i.
In practice, many of the engineering techniques used, such as grounding and shielding, apply to all three issues. EMC ensures the correct operation, in the same electromagnetic environment, of different equipment items which use or respond to electromagnetic phenomena, and the avoidance of any interference effects. Another way of saying this is that EMC is the control of EMI so that unwanted effects are prevented.
Besides understanding the phenomena in themselves, EMC also addresses the countermeasures, such as control regimes, design and measurement, which should be taken in order to prevent emissions from causing any adverse effect. Electromagnetic interference divides into several categories according to the source and signal characteristics.
This type is naturally divided into sub-categories according to frequency range, and as a whole is sometimes referred to as “DC to daylight”. Mains hum from: power supply units, nearby power supply wiring, transmission lines and substations. Audio processing equipment, such as audio power amplifiers and loudspeakers. Demodulation of a high-frequency carrier wave such as an FM radio transmission.
Broadband noise may be spread across parts of either or both frequency ranges, with no particular frequency accentuated. The energy is usually broadband by nature, although it often excites a relatively narrow-band damped sine wave response in the victim. Sources divide broadly into isolated and repetitive events. Switching action of electrical circuitry, including inductive loads such as relays, solenoids, or electric motors.
Electrical ignition systems, such as in gasoline engines. Continual switching actions of digital electronic circuitry.