Wegener UNITY4650, Руководство пользователя

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Unity 4650 User’s Manual
800034-01 Rev. A 20 wegener.com
Audio Language
Descriptor Legacy 3-character MPEG descriptor applied to a program’s audio streams. It was origi-
nally allocated to designate languages, but is now used for generic identification.
Automated Recovery
(or Recovery) The mechanism used when the U4650 is unable to acquire a valid transport stream, loses
network control or detects an invalid control stream, or is unable to deliver the required
services using its current settings. The unit automatically begins attempting operations
under "backup" unit settings stored in the presets table until it can return to normal opera-
tion or is stopped by local user command.
Boot loader Software residing in non-writable zone of flash which executes at unit reset. It will verify
and load the preselected application.
CA See "Conditional Access".
COMPEL

Wegener's network control software that may be used to manage your U4650 as well as
other hardware.
Conditional Access Wegener’s system for securing the transmitted transport stream from unauthorized
access. It features distribution of ciphered authorizing messages within a special PID.
Upon deciphering in secure processors within the IRD, these messages continuously
update the IRD with the current descrambling key.
DPI Digital Program Insert. A special message, borne in an MPEG PID associated with a par-
ticular program, that signals the boundaries of ad avails.
DTMF Dual-Tone Multi-Frequency. Tone signaling system used by the legacy telephone system.
Tone pairs represented each of the keyboard items 0-9, *, and #. This system may be used
to control external cueing equipment.
DVB Digital Video Broadcast working group. This is a shorthand designation for a group of
industry standards that provide enhancements in the use of MPEG transport streams. (For
example, one DVB standard defined the standard way QPSK-modulated carriers would
convey these streams over satellite world-wide.)
E
b
/N
0
Energy-per-bit per Noise density-per-Hertz. This is a unitless ratio that expresses signal-
to-noise ratio in carrier transmission systems that convey digital data. A quality measure-
ment for any such system is the E
b
/N
0
needed to just convey the digital data within
acceptable error rates. This is called the “E
b
/N
0
threshold”.
Errored seconds see ERT.
ERT Error Rate Threshold. Per DVB, that input RF signal-to-noise ratio, expressed as "E
b
/N
0
",
where the receiver card detects an average of one transport packet with uncorrected errors
per one-hour interval. Wegener defines a similar metric of an average of one errored sec-
ond per hour, where an "errored second" is any one-second interval in which one or more
transport packets contains uncorrected errors.
Ethernet The widely-used LAN technology specified by IEEE standard 802.3
Table 3: Glossary of Terms
Term Definition