Electromagnetic compatibility
In telecommunication, the term electromagnetic compatibility (EMC) has the following meanings:
1. Electromagnetic compatibility is the condition which prevails when telecommunications equipment is performing its individually designed function in a common electromagnetic environment without causing or suffering unacceptable degradation due to unintentional electromagnetic interference to or from other equipment in the same environment.
2. The ability of systems, equipment, and devices that utilize the electromagnetic spectrum to operate in their intended operational environments without suffering unacceptable degradation or causing unintentional degradation because of electromagnetic radiation or response. It involves the application of sound electromagnetic spectrum management; system, equipment, and device design configuration that ensures interference-free operation; and clear concepts and doctrines that maximize operational effectiveness.
Source: from Federal Standard 1037C and from the NTIA Manual of Regulations and Procedures for Federal Radio Frequency Management and from the Department of Defense Dictionary of Military and Associated Terms
In the past a relaxed EMC regime existed, and equipment manufacturers did not care much about EMC issue's. However, because of increases of clock speeds used in modern digital equipment coupled with the lower signal voltages these systems used, EMC became more and more an issue.
Many nations became aware of this growing problem and issued directives to the manufacturers of these kind of equipment, which set out the essential requirements which must be satisfied before such equipment may be sold.
Organizations in each nation where set up to draw up and safeguard these directives.
Among the more well known national organizations are:
The FCC for the United states. CEN, CENELEC and ETSI for Europe and BSI for Britain.
There are also several international organizations who try "to promote international co-operation on all questions of standardization" (harmonisation), including EMC standards.
The most important international organisation is the International Electrotechnical Commission (IEC), which has several committees working full time on EMC issues.
These are "TC77" working on "electromagnetic compatibility between equipment including networks", and the International Special Committee on Radio interference (CISPR).
Co-ordination of the IEC's work on EMC between these committees is the responsibility of the ACEC, the advisory committee on EMC.
See also spread spectrum and List of EMC directives
External link
Search newsgroup sci.engr.electrical.compliance for EMC related postings