E

	Earth Station
	The term used to describe the combination or antenna, low-noise amplifier (LNA), down-converter, and receiver electronics used to receive a signal transmitted by a videoconference.
	Echo-cancellation
	Process, which attenuates or eliminates the acoustic echo effect on videoconference calls. Echo cancellers are largely replacing obsolete echo suppressers.
	Echo Effect
	A time-delayed electronic reflection of a speaker's voice. This is largely eliminated by modern digital echo cancellation.
	Echo suppression
	To reduce annoying echoes in the audio portion of a videoconference, it silences all sound when on by temporarily deadening the communication link in one direction. Unfortunately, not only the echo is stopped but also the remote end's new speech, which results in clipping.
	EIRP (Effective Isotropic Radiated Power)
	This term describes the strength of the signal leaving the videoconference antenna or the transmitting earth station antenna. The transmit power value in units of dBW is expressed by the product of the transponder output power and the gain of the videoconference transmit antenna.