Wegener Communications UNITY 4600 - Manual (Page 19)

www.wegener.com 800032-01 Rev. G 13
Unity 4600 User’s Manual
Ethernet The widely-used LAN technology specified by IEEE standard 802.3
IRD Integrated Receiver-Decoder. A product which features a "receiver" to extract transport
streams from satellite-borne carriers and a companion "decoder" to decompress MPEG
elementary streams (from within said transport streams) in order to recreate the original
audio/video/data signals. The
Unity 4600 is an IRD.
Keep-alives
(COMPEL)
Simple COMPEL network messages, addressed to "all", bearing date and time.These are
transmitted regularly (every 5 seconds, for example) so that IRDs may quickly and
continuously verify their network connection.
KMS Key Management System. The sub-system within the Wegener Conditional Access system
that creates and ciphers the scrambling keys and then distributes them to the uplink
UMX5010 and all downlinked IRDs conveyed in a special PID within the transport stream.
LAN Local area network. Your Unity 4600 may be connected to an Ethernet LAN.
LCD Liquid crystal display. The front-panel screen on your Unity 4600 is a liquid crystal display.
LED Light-emitting diode. The front-panel indicator lights on your Unity 4600 are LEDs
Mbps, kbps or Msps Units of data transport rate - Megabits per second (1 million bits per second), kilobits per
second (1 thousand bits per second), or million symbols per second (1 million symbols per
second)
MPEG Moving Picture Experts Group - refers to the method of video compression established by
this group. (The
Unity 4600 utilizes the MPEG2 format for video.)
Network Protection
Mode A non-volatile setup parameter whose value is “Shared” or “Protected” (or “not Shared”).
Similarly, each network control stream has a “Share” status field as part of the COMPEL
packet framing. A network control stream is considered “invalid” to the
Unity 4600 if the
network ID in the stream differs from that of the IRD and if either the network stream or the
Unity 4600 are set to be “Protected”. For test purposes only, there is a generic network ID
that the COMPEL system may transmit which is always considered to be “valid” by all IRDs.
NTSC National Television System Committee. The composite color video standard used
domestically (and in a few countries outside US) based on 525-line 59.97 Hz field rate (with
2:1 interlace).
PAL Phase-Alternating-Line. A set of composite color video standards used worldwide (outside
US) which implements a line-by-line reversal of phase of one of the orthogonal color
components. For our use, all PAL signals are assumed to be 625-line 50 Hz field-rate
systems with varying chroma and luma bandwidths and color subcarrier frequencies.
PAT Program Allocation Table. A PSI table within an MPEG transport stream which cross-
references all available programs to a PID for its PMT. This table is always present in legal
transport streams and must always be in the clear (not scrambled) even when Conditional
Access scrambling is used.
PCR Program Clock Reference. A time-base signal used to synchronize the IRDs internal timing
to the same timing in the MPEG encoder for the received program. Multiple programs may
share a PCR, depending on the multiplexer used to create the final transport stream.
PES Stream Packetized Elementary Stream. The MPEG designation for a compressed component of a
Program (such as audio or video) which includes the timing information necessary for
synchronization (e.g. - synchronizing audio to video).
PID (or Packet ID) The unique transport stream packet identifier assigned to each constituent data stream
within the transport stream. Also, in this document, “PID” is used to designate the stream
itself.
Term Definition