All of the above effects can be categorized into three basic spheres of EMC compliance, which every high-tech product developer needs to manage. These are:

• INTENDED EMISSIONS (Conducted & Radiated)*: Regulation of communications systems and products and regulation of the electromagnetic spectrum.
• UNINTENDED (INCIDENTAL) EMISSIONS (Conducted & Radiated)*: Protection of adjacent entities from energy emitted from a product. Products must not pollute.
• SUSCEPTIBILITY (IMMUNITY) (Conducted & Radiated)*: Protection of an entity from energy emitted by adjacent electronic products and electrostatic generators (e.g. people, lightning). A product must be immune to pollution.

* For most industrial and consumer products and systems EMC effects can exit or enter equipment through the power cords or cables (conducted EMC), through the air or space (radiated EMC) and by electrical 'sparks' to the product itself or to it's connected cables by ElectroStatic Discharge and lightning (ESD). Your product most likely has all three issues to contend with. Even hand-held or portable products can still have conducted EMC problems if they are connected to battery chargers and 'down/up-load' cradles.

A brief overview of intended EMC

• Spectrum control: The regulatory organizations divide the electromagnetic spectrum into pieces where each piece is reserved for specific uses by specific groups. For example, see:
  
  

  http://www.ntia.doc.gov/osmhome/allochrt.pdf



• Transmitted radiation control: A device or system must limit the power it can transmit, depending on which piece of spectrum it is allowed to operate, and the amount of energy it can present to biological systems (e.g. Maximum Permissible Energy - MPE and Specific Absorption Ratio - SAR).

Equipment examples are cell phones, radio/TV stations, public/military communications systems, portable home phones and WiFi and Bluetooth products.

This part of EMC compliance is usually well controlled and well planned during the design and testing stage by RF and antenna engineers, since intended emissions are part of the functional and performance requirements of the technical design. The circuitry is designed to generate or detect very specific emissions of very specific power levels and radiation characteristics.