Jargon Buster

22 khz tone

The signal generated by a satellite receiver and relayed to an LNB to select the 'high' oscillator.

ADSL

'Asynchronous Digital Subscriber Loop'

Amplifier

A circuit that increase the power or voltage of a signal.

Amplitude modulation

A transmittion system in which the modulating waveform is made to vary the the carrier amplitude.

Analogue

A mode of transmission of information.  An analogue waveform has a physical similarity with the quantity it represents.

Antenna (aerial)

A device used to transmit or receive radio waves.

Aspect ratio

The ratio of width to height for a TV screen.

Astra

The trade name for satellites operated by SES ('societe Europeenee des Satellits').

Attenuator

A passive device that decreases signal power.

Azimuth

A compass bearing East or West of true South.

Balun

A balance to unbalance transformer (sometimes an integral part of an aerial) used to match an unbalanced coaxial cable to a balanced device such as an aerial dipole or receiver input.

Bandpass filter

A circuit that passes a restricted band of frequencies.  Unwanted lower and upper frequencies are attenuated.

Bandwith

The total range of frequencies occupied by a signal.  It is normally measured between half power points.

Baseband

The band of frequencies containing information after demodulation.

Beamwidth

An aerial acceptance angle measured between half power points.

Bit

A binary digit (a 1 or 0).

Bit error ratio (BER)

A ratio of the number of errors in a data stream to the total number of data bits.

Bit rate

The number of digital bits transmitted per second.

Boltzmann's constant

The relationship between the energy of a particle and its motion is related to its absolute temperature multiplied by Boltzmann's constant, which has a value of -228.6dB.  This very small factor exerts a powerful influence on the effects of noise and thus quality.

Boresight

The principle center axis of an aerial or dish antenna.

Bouquet

A number of programmes grouped within a multiplex.

BSkyB

British Sky Broadcasting.

BSS (Bus. Satellite Services)

The band of frequencies 11.7-12.5ghz.

Byte

A group of 8 digital 'bits'.

 



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