Vislink NewStream, Руководство пользователя и техническое руководство

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Page 110
NewS
tream
User Guide and Technical Manual
Term Defi nition
ABR Adaptive Bit-rate
ABR encoding dynamically adjusts an encoder’s output bit-rate to accommodate
available upload speeds across several networks.
Aggregation Aggregation refers to the reconstruction and reordering of separate, packetized,
video transport streams into a single coherent video stream, as the streams
arrive at an IP - addressed destination. As an example, a LiveGear Receiver
aggregates video feed from an
NewS
tream
transmitter for decoding. Similarly,
the VMS-1000 also aggregates a video signal for distribution over the Web.
APN Access Point Name
APN is a con
fi gurable network identi fi er used by a mobile device when
connecting to a GSM carrier. The carrier examines the APN identi fi er to
determine the network connection type for the NewS
tream
transmitter. The
APN determines which IP addresses should be assigned to NewS
tream
, which
security methods should be used, and how or if, it should be connected to a
private network.
ASI Asynchronous Serial Interface
ASI refers to a streaming data format that often carries an MPEG Transport
Stream. This serial communications interface operates at up to 270 Mbit/sec.
ASI is generally used in
fi eld news-gathering operations.
Band [RF] This refers to the RF band to which the AirCam is calibrated. To receive RF
signals an antenna is used by the AirCam with a radio tuner to adjust to a
particular frequency range within the RF band. This tuning is accomplished using
a resonator – a circuit with a capacitor and an inductor forming a tuned circuit.
The resonator ampli
fi es oscillations within a particular frequency band, while
reducing oscillations at other frequencies outside the band.
BAS Broadcast Auxiliary Service
BER Bit Error Ratio
The Bit Error Rate is the percentage of bits that have errors relative to the total
number of bits in the signal. The rate is an indication of how often a packet or
other data unit has to be retransmitted because of an error.
BISS-1 Basic Inter-operable Scrambling System-1
BISS is a satellite signal scrambling system. BISS-1 transmissions are protected
by a 12 digit hexadecimal session key that is agreed by the transmitting and
receiving parties prior to transmission. The key is entered into both the encoder
and decoder. The key forms part of the encryption of the digital television signal
Any receiver with BISS support and the correct key will be able to decrypt the
signal.