Ericsson MX8400, Справочное руководство

Страница: 118 / 226

Glossary
Multicast An IP mechanism that allows transmission of data to multiple
receivers. A multicast can also have several transmit sources
simultaneously. In video applications, multicast is typically used to
distribute a video signal from a central source to multiple
destinations.
MUSICAM Masking pattern adapted Universal Sub-band Integrated Coding
And Multiplexing: An audio bit rate reduction system relying on sub-
band coding and psychoacoustic masking.
Mux Multiplexer: Transmission Multiplexer: receives EMMs from the
ACC, ECMs from the BCC, video/audio data from the encoders, and
the SI stream from the SIC. It then multiplexes them all into a single
DVB-compliant transport stream, and delivers the signal to the
uplink after modulation.
The Multiplexer also contains the cypher card, which scrambles the
services according to the control words supplied by the BCC.
Network In the context of broadcasting: a collection of MPEG-2 transport
stream multiplexes transmitted on a single delivery system, for
example, all digital channels on a specific cable system.
NICAM Near Instantaneously Companded Audio Multiplex: Official name is
NICAM 728. Used for digital stereo sound broadcasting in the UK
employing compression techniques to deliver very near CD quality
audio. 728 refers to the bit rate in kbps.
NIT Network Information Table: Part of the service information data. The
NIT provides information about the physical organization of each
transport stream multiplex, and the characteristics of the network
itself (such as the actual frequencies and modulation being used).
nm Nanometre: a unit of length equal to one thousand millionth (10
-9
) of
a metre.
NMS Network Management System. A system used to supervise
elements in an IP network. When a device reports an alarm, the
alarm will be collected by the NMS and reported to the operator.
NMS systems typically collect valuable statistics information about
the network performance and can warn the operator early.
NTSC National Television Systems Committee: The group, which
developed analogue standards used in television broadcast systems
in the United States. Also adopted in other countries (e.g. Mexico,
Canada, Japan). This system uses 525 picture lines and a 59.97 Hz
field frequency.
NVOD Near Video On-Demand: Method of offering multiple showings of
movies or events. The showings are timed to start at set intervals,
determined by the broadcaster. Each showing of a movie or event
can be sold to subscribers separately.
NVRAM Non-volatile Random Access Memory: Memory devices (permitting
random read / write access) that do not lose their information when
power is removed. Stores the default configuration parameters set
by the user.
ODU Outdoor Unit
2/1553-FGC 101 1014 Uen B A-12