See Bit Error Rate.

See Bit Error Rate.

Quadrature Amplitude Modulation. A method of combining two Amplitude Modulated (AM) signals - each having the same frequency, but differing in phase by 90 degrees, into a single channel, thereby doubling the effective bandwidth.

The length of the path between a communications satellite and an associated earth station.

Video-On-Demand. System that allows the viewer to see or choose a programme at the time the viewer specifies.

The method of channel sharing or utilisation of a single frequency or time slot by several locations.

A device used to increase the strength of electrical signals.

A form of storing, processing or transmitting information through a continuous variable (rather than pulsed) signal.

Device which picks up and delivers satellite signals to a receiver, most commonly a dish.

A cross sectional area of the antenna which is exposed to the satellite signal.