Amplitude Modulation
Process by which the amplitude of a carrier wave is varied following a specified law.

Anechoic Chamber
Shielded enclosure which is lined with radio-frequency absorbers to reduce reflections from internal surfaces.

Antenna
Transducer which either emits radio-frequency power into space from a signal source or intercepts an arriving electromagnetic filed, converting it into an electrical signal.

CENELEC
The European Organisation for Electrotechnical Standardisation.

Class A Digital Device
A digital device that is marketed for use in a commercial, industrial or business environment, exclusive of a device which is marketed for use by the general public or is intended to be used in the home.

Class B Digital Device
A digital device that is marketed for use in a residential environment notwithstanding use in commercial, business and industrial environments. Examples of such devices include, but are not limited to, personal computers, calculators, and similar electronic devices that are marketed for use by the general public.

Continuous Waves (CW)
Electromagnetic waves, the successive oscillations of which are identical under stead-state conditions, which can be interrupted or modulated to convey information.

Coupling
Interaction between circuits, transferring energy from one circuit to another.

Coupling Clamp
Device of defined dimensions and characteristics for common mode coupling of the disturbance signal to the circuit under test without any galvanic connection to it.

Coupling Network
Electrical circuit for the purposes of preventing EFT voltage applied to the EUT from affecting other devices, equipment or systems which are not under test.

De-coupling Network
Electrical circuit for the purpose of preventing EFT voltage applied to the EUT from affecting other devices, equipment or systems which are not under test.

Degradation
An undesired departure in the operational performance of any device, equipment or system from its intended performance.

EFT/B
Electrical fast transient/burst.

Electrical Installation
An assembly of associated electrical equipment to fulfil a specific purpose or purposes and having co-ordinated characteristics.

Electrical Compatibility
The ability of an equipment or system to function satisfactorily in its magnetic environment without introducing intolerable electromagnetic disturbances to anything in that environment.

Electromagnetic (EM) Wave
Radiated energy produced by the oscillation of an electric charge characterised by oscillation of the electric and magnetic fields.

EUT
Equipment under test.

Far Field
Region where the power flux density from an antenna approximately obeys an inverse square law of the distance.

Field Strength
The term "field strength" is applied only to measurements made in the far field. The measurement may be of either the electric or the magnetic component of the field and may be expressed as V/m, A/m or W/m2; any of these may be converted to the other.

Frequency Band
Continuous range of frequencies extending between two limits.

Front Time (surge voltage)
The front time T1 of a surge voltage is a virtual parameter defined as 1.67 times the interval T between the instant when the impulse is 30% and 90% of the peak value.

Front Time (current surge)
The front time T1 of a surge current is a virtual parameter defined as 1.25 times the interval T, between the instants when the impulse is 10% and 90% of the peak value.

Ground (reference) Plane
A flat conductive surface whose potential is used as a common reference.

IEC
The International Electrotechnical Commission, headquarters in Geneva, Switzerland.

Immunity (to a disturbance)
The ability of a device, equipment or system to perform without degradation in the presence of an electromagnetic disturbance.

Induction field
Predominate electric and/or magnetic field existing at a distance d<l /2p , where l is the wavelength.

In-situ
Location where the equipment is installed for its normal use by the end user.

Isotropic
Having properties of equal values in all directions.

Polarization
Orientation of the electric field vector of a radiated field.

Port
Particular interface of the EUT with the external electromagnetic environment.

Primary Protection
The means by which the majority of stressful energy is prevented from propagating beyond the designated interface.

Rise time
The interval of time between the instants at which the instantaneous value of a pulse first reaches 10% value and then the 90% value.

Secondary Protection
The means by which the let-through energy from primary protection is suppressed.

Spurious Radiation
Any undesired electromagnetic emission from an electrical device.

Surge
A transient wave of electrical current, voltage or power propagating along a line or a circuit and characterised by a rapid increase followed by a slower decrease,

Test Site
A site meeting the requirements necessary for correctly measuring, under defined conditions, electromagnetic fields emitted by a device under test.

Transceiver
Combination of radio transmitting and receiving equipment in a common housing.

Transient
Pertaining to or designating a phenomenon or a quantity which varies between two consecutive steady states during a time interval which is short compared with the time-scale of interest.