Electromagnetic Compatibility (EMC)

EMC is defined as:

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.

What Actually Causes EMI Problems:

• Failure to adequtely define environments
• Failure to assess EMI impact on key performance parameters
• Failure to accomplish adequate EMC testing evaluation
• Failure to "grow" sufficient numbers of qualified EMC engineers

Equipment Malfunctions due to EMI

Interference Mechanisms

• Cochannel Interference
• Adjacent channel Interference     
  • Transmitter noise
  • Suprious Emissions (Responses)
• Harmonic Interference
• Intermodulation Products
• High Power Effects     
  • Receiver stauration/Desensitization
  • Burnout

EMC 101

The main reasons that EMC is becoming an important aspect of elctronic equipment design are:

• Electronic equipment and devices are becoming more prolific - these electrical/electronic devices are the mainstay of the modern environment and will not go away
• Current and future electronic equipment will operate at higher and higher frequencies and will utilize higher data rates
• Current and future electronic equipment will use lower voltages that reduce power consumption and render the equipment more vulnerable to EMI
• Analog signals are a thing of the past - most data signals and data links today are digital, and are designed to encompass as many separate channels as possible using up bandwidth and limited spectrum