Ericsson SVP 2000, Reference Manual, Page: 170 / 196

Glossary
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.
QoS Quality of Service. A common term for a set of parameters
describing the quality you get from an IP network: Throughput,
availability, delay, jitter and packet loss.
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 quantization 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 Ericsson AB proprietary public-key
encryption system used to prevent unauthorized viewing of a TV
programme or programmes.
Reflex™ An Ericsson AB proprietary system to provide efficient use of
bandwidth by a set of encoders without sacrificing picture quality. A
group bit rate is allocated to a set of Encoders and the bit rate for
each encoder is allocated according to the requirements of the
picture encoding process.
The bit rate allocation can be performed externally by a multiplexer,
or internally in a unit fitted with multiple VCM’s.
RF Radio Frequency.
RGB Red, Green, Blue: The Chroma information in a video signal.
RIP2 Routing Information Protocol v2. A protocol used between network
routers to exchange routing tables and information.
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.
RSVP ReSerVation Protocol. A Quality-of-service oriented protocol used
by network elements to reserve capacity in an IP network before a
transmission takes place.
EN/LZT 790 0046/1 R1A A-16