Electronic devices that can function and meet the criteria are called electromagnetically compatible devices.
Electromagnetic compatibility or EMC is a branch of electrical sciences that deals with the unintentional propagation, generation and reception of unwanted electromagnetic interference or EMI that such energy may induce.
One very good technique to reduce EMI is the spread spectrum technique which modulates the signal and spreads the energy over a wider range of frequency.
Spread spectrum controls and modulates the clock signal so that it does not contribute significantly to jitter.
It has been successful demonstrated that by using spread spectrum, radiation can be lowered from 7dB to 20dB depending on the degree of modulation.
The goal of Electromagnetically Compatibility is to achieve the correct operation in the same environment of different types of electrical devices that use electromagnetic phenomena, and the avoidance of any interfering effects.
This is achieved by pursuing two different kinds of issues, and these issues are emission and susceptibility.
Emissions are related to any undesirable generation of electromagnetic by whatever source, and also to countermeasures, which should be taken so as to minimalise such generation and to avoid the escape of remaining energies into the external environment.
In contrast, susceptibility issues are aimed at the correct functioning of electrical equipment which are referred to as the victim when in the presence of any unwanted electromagnetic disturbances.
Electromagnetic compatibility is achieved mainly when addressing susceptibility and emission issues; in other words; hardening the potential victim and quieting the sources of interference.
Also the path between victim and source can be addressed to increase even better results.
In today's busy offices electromagnetic interference is usually a result of the higher clock speeds found in PCs and workstations.
The radiation of this interference which is mainly produced by low order harmonics, can coincide and interfere with many radio FM bands, and regulatory agencies have been forced to place limits on electromagnetic radiation which is produced by electronic instruments and PCs that may use clocks and generate unacceptable emissions.