7E Communications
   

Glossary Terms Beginning E

0-9 : A : B : C : D : E : F : G : H : I : J : K : L : M

N : O : P : Q : R : S : T : U : V : W : X : Y : Z

Earth station
Generic term for any transmitting or receiving station for satellite transmissions.
Eb/N0
Energy per bit to noise density ratio.
Edge of coverage
Limit of a satellite's defined service area. In many cases, the EOC is defined as being 3 dB down from the signal level at beam centre, though reception may still be possible beyond the -3 dB point.
Efficiency
Property of an antenna: typically 55-70% for an SNG antenna.
EIRP
Effective isotropic radiated power: defines the total system power in dBW; describes the strength of the signal leaving the satellite antenna or the uplink antenna, and is used in determining the C/N and S/N.
Elevation
Upward tilt of an antenna measured in degrees, required to point accurately the antenna at the satellite; angle of tilt (inclination) of an uplink antenna; the angle of the direct path to the satellite above the horizon.
EMC
Electromagnetic compatibility: generic term for a Directive of the EU covering electromagnetic interference (EMI).
EMI
Electromagnetic interference.
Encoder
Device used to digitally compress the video and audio signals for transmission.
Encryption
Process of encoding or scrambling television signals so that unintended audiences are unable to view the signal.
Entropy
The useful information content of a signal.
Ephemeris data
Data regularly published by satellite operators describing cyclical influences of gravity from the Sun and the Moon, as well as solar radiation. These all affect the positioning of the satellite.
Error correction
Process where bits are added in the modulation of a digital signal to correct for errors in transmission.
ETSI
European Technical Standards Institute: established in 1988 on the joint initiative of the EU and the CEPT to produce technical standards for telecommunications across the EU.
Exciter
Generic term for the combination of an analogue modulator and upconverter, which provides the drive signal to the input of an HPA.