Ericsson RX1290 Betriebsanweisung PDF herunterladen (Seite 89)

Glossary

Reference Guide: RX1290 H.264 Contribution Receiver Page A-11

ST.RE.E10228.1

PSI Program Specific Information: Consists of normative data, which is necessary for the

demultiplexing of transport streams and the successful regeneration of programs. (See also:

SI).

PSIP Program System Information Protocol: The ATSC equivalent of SI for DVB.

PSK Phase Shift Keying: A method of modulating digital signals particularly suited to satellite

transmission.

PSR Professional Satellite Receiver: See also: IRD.

PSU Power Supply Unit.

QAM Quadrature Amplitude Modulation: A method of modulating digital signals, which uses

combined techniques of phase modulation and amplitude modulation. It is particularly suited

to cable networks.

QPSK Quadrature Phase Shift Keying: A form of phase shift keying modulation using four states.

QSIF Quarter Screen Image Format.

Quantise A process of converting analogue waveforms to digital information. 8-bit quantisation as set

out in ITU-R Rec. 601. uses 256 levels in the range 0 – 255 to determine the analogue

waveform value at any given point. The value is then converted to a digital number for

processing in the digital domain.

RAM Random Access Memory: A volatile storage device for digital data. Data may be written to,

or read from, the device as often as required. When power is removed, the data it contains is

lost.

RAS Remote Authorization System: A TANDBERG TV proprietary public-key encryption system

used to prevent unauthorized viewing of a TV programme or programmes.

RF Radio Frequency.

RGB Red, Green, Blue: The Chroma information in a video signal.

ROM Read Only Memory: A non-volatile storage device for digital data. Data has been stored

permanently in this device. No further information may be stored (written) there and the data it

holds cannot be erased. Data may be read as often as required.

RS Reed-Solomon coding: An error detection and correction, coding system. 16 bytes of Reed-

Solomon Forward Error Correction code are appended to the packet before transmission

bringing the packet length to 204 bytes. The 16 bytes are used at the receiving end to correct

any errors. Up to eight corrupted bytes can be corrected.

RLC Run Length Coding: Minimisation of the length of a bit-stream by replacing repeated

characters with an instruction of the form ‘repeat character x y times’.

SCPC Single Channel Per Carrier.

Spectral Scrambling A process (in digital transmission) used to combine a digital signal with a pseudo-random

sequence, producing a randomised digital signal that conveys the original information in a

form optimised for a broadcast channel.

Scrambling Alteration of the characteristics of a television signal in order to prevent unauthorised

reception of the information in clear form.

SDI Serial Digital Interface.

SDT Service Description Table: Provides information in the SI stream about the services in the

system; for example, the name of the service, the service provider, etc.

SELV Safety Extra Low Voltage (EN 60950).

STB Set-Top Box: A box that sits on top of a television set and is the interface between the home

television and the cable TV company. New technologies evolving for set-top boxes are video-

on-demand, video games, educational services, database searches, and home shopping. The

cable equivalent of the IRD.

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