TANDBERG TT1260 Reference Manual page 96

Glossary
PPV
Program
Programme
P P
R B
PROM
PS
PSI
PSIP
PSK
PSR
PSU
PTS
QAM
QPSK
QSIF
Quantise
RAM
RAS
RF
ROM
RS
RLC
SCPC
Spectral Scrambling
Scrambling
SDI
SDT
SELV
STB
STT
Page A-8
Pay Per View: A system of payment for viewing services based on a usage / event basis rather than on on-going
subscription. Subscribers must purchase viewing rights for each PPV event that they wish to view. PPV events
may be purchased as IPPV or OPPV.
PC - A sequence of instructions for a computer.
TV - A concept having a precise definition within ISO 13818-1 (MPEG-2). For a transport stream, the timebase is
defined by the PCR. The use of the PCR for timing information creates a virtual channel within the stream.
A linking of one or more events under the control of a broadcaster. For example, football match, news, film show.
In the MPEG-2 concept, the collection of elementary streams comprising the programme, have a common start
and end time. A series of programmes are referred to as events.
Analogue Colour difference signals. Refer to C
Programmable Read-Only Memory: A device, which may be written once with data for permanent storage, and
then read whenever required. Special types of PROM permit the erasure of all data by Ultraviolet light (EPROM) or
by application of an electronic signal (EEPROM).
Program Stream: A combination of one or more PESs with a common timebase.
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).
Program System Information Protocol: The ATSC equivalent of SI for DVB.
Phase Shift Keying: A method of modulating digital signals particularly suited to satellite transmission.
Professional Satellite Receiver: See also: IRD.
Power Supply Unit.
Presentation Time Stamp (ATSC).
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.
Quadrature Phase Shift Keying: A form of phase shift keying modulation using four states.
Quarter Screen Image Format.
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.
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.
Remote Authorization System: A TANDBERG TV proprietary public-key encryption system used to prevent
unauthorized viewing of a TV programme or programmes.
Radio Frequency.
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.
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.
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'.
Single Channel Per Carrier.
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.
Alteration of the characteristics of a television signal in order to prevent unauthorised reception of the information
in clear form.
Serial Digital Interface.
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.
Safety Extra Low Voltage (EN 60950).
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.
System Time Table (ATSC).
C for an explanation.
R B
Reference Guide: TT1260 Contribution Receiver
ST.RE.E10100.1