Back Match

The matching of the resistive values of the input and output of electronic devices to reduce signal reflection and ghosting. Also known as impedance matching.

Backfire

A dual reflector feed system of undefined geometry.

Backhaul

A terrestrial link connecting an earth station to its local switching center or population center.

Back Porch

That portion of the horizontal blanking pulse that follows the trailing edge of the horizontal sync pulse.

Band

A unit for designating a specific frequency or range of frequencies in the electromagnetic spectrum.

Band Separator

A device that splits a group of specified frequencies into two or more bands. Common types include UHF/VHF, Hi/Lo band and FM separators. This device is essentially a set of filters.

Bandpass Filter

A circuit or device that allows only a specified range of frequencies to pass from input to output.

Bandwidth

The range of frequencies occupied by a signal, or passed by a transmission channel. Services requiring a bandwidth greater than 20 kHz, such as TV transmissions, are known as "broadband". Those requiring less capacity, such as audio transmissions, are known as "narrowband".

Baseband

The band of frequencies containing the information, prior to modulation (and after demodulation).

Basic cable service

In the US, it is the programming package delivered on cable systems eligible for regulation by local franchising authorities under 1992 Cable Act, including all local broadcast signals and PEG (public, educational and government) access channels.

Baud

Unit of data transmission rate, based on the number of signal elements or symbols transmitted per second.

BB

Baseband.

BCD

Binary coded decimal.

BDC

Block Downconverter or Block Downconversion.

Beacon

Low-power carrier generated by an auxiliary transmitter. May be unmodulated for propagation tests or tracking, or modulated with telemetry or tracking data.

Beam Hopping

The capability of satellites to shift their beam rapidly - in a matter of milliseconds - so that data can be sequentially processed from multiple earth stations.

Beam width

The acceptance angle of an antenna, usually measured between half-power (3 dB) points.

Bearer Circuit

One circuit that can be divided by circuit multiplication equipment to carry more than one derived circuit.

BER (or b.e.r.)

Bit Error Rate. Accuracy of digital demodulation or decoding. Analogous to SNR, but in digital transmission.

Bird

Jargon or nick name for communication satellites.

Bit Rate

Speed of digital transmission, measured in bits per second (bits/s or b/s), or multiples of thousands or millions (Kbits/s or kb/s; Mbits/s or Mb/s).

Bit

A binary digit. Smallest possible unit of digital transmission.

Blanking Level

The level of composite vidoe signal that seperates the spectra containing video information from the spectra containing synchronizing information.

Blanking Signal

Pulses used to extinguish the scan illumination during horizontal and vertical retrace periods.

Blanking Pulse level

The reference level for video signals which occurs between succeeding picture frames. The blanking interval contains synchronizing information, and in some cases, teletext signals.

Block Downconversation

The use of fixed-frequency first local oscillator, to downconvert an entire satellite band to a lower intermediate frequency for subsequent tuning and demodulation.

BNC Connector

A weatherproof twist lock coax connector standard on commercial video equipment and used on some brands of satellite receivers.

BO

Backopff (of non-linear system, from saturation). In a satellite transponder, may be qualified as input backoff or output backoff.

BOL

Beginning of Life (of a transponder or satellite).

Boresight

The direction along the principle axis of either a transmitter or a digital antenna.

Box

A set top converter which replaces the television's tuner thus expanding the television set's channel tuning capability.

BPF

Band-Pass Filter.

BPSK

Binary Phase - Shift keying.

BPU

Baseband Processor Unit.

Braid Carrier

A spool or bobbin on a braider which holds one group of strands or filaments consisting of a specific number of ends. The carrier revolves during braiding operations.

Braid Angle

The smaller of the two angles formed by the shielding strand and the axis of the cable being shielded.

Braid Ends

The number of strands used to make up one carrier. The strands are wound side by side on the carrier bobbin and lie parallel to the finished braid.

Braid

A fiberous or metallic group of filaments interwoven in cylindrical form to form a covering over one or two wires.

Breakdown Voltage

The voltage at which the insulation between two conductors breaks down.

Broadband

A device that processes a signal(s) spanning a relatively broad range of input frequencies.

Broadcast

A signal transmitted to all user terminals in a service area, or the process.

BS

Broadcasting Satellite (Japan)

b/s

Abbreviation for Bits per second.

Bunch Stranding

A group of wires of the same diameter twisted together without a predetermined pattern.

Buried Cable

A cable installed directly in the earth without use of underground conduit. Also called "direct burial cable".

Buttonbook Feed

A rod shaped like a question mark supporting the feedhorn and LNA. A buttonhook feed for use with commercial grade antennas is often a hollow waveguide that directs signals from a feedhorn to an LNA behind the antenna.

Byte

A digital "word," usually consisting of eight bits.