Tait P25 CG, Инструкция по установке и эксплуатации

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TB9100/P25 CG Installation and Operation Manual TaitNet P25 Glossary 145
© Tait Electronics Limited January 2007
uplink
The transmission path from SUs to fixed equipment.
UTC
Coordinated Universal Time (word order from French). An international time
standard that has replaced Greenwich Mean Time.
V
valid signal A valid signal is a signal that the receiver unmutes to. A signal is valid, for
example, when it is strong enough to be decoded and when it has the specified
NAC.
vocoder
Voice encoder/decoder. A processing element that compresses/decompresses
the digital voice signal.
voice stream
A digitized voice signal that passes through the main switch.
VoIP
Voice over IP. The name for the technology that puts speech signals in packets
and then routes them over an IP backbone network.
voting
Voting is the systematic sampling of a group of channels for the channel with
the greatest signal strength. Voting provides wide-area coverage and ensures
that as the user moves throughout the coverage area the strongest channel is
always available for a call.
VPN
Virtual private network. A private communications network used to
communicate confidentially over a non-private network.
VSWR
Voltage Standing Wave Ratio (VSWR) is the ratio of the maximum peak
voltage anywhere on the transmission line to the minimum value anywhere on
the transmission line. A perfectly matched line has a VSWR of 1:1. A high ratio
indicates that the antenna subsystem is poorly matched.
W
watchdog
A watchdog circuit checks that the system is still responding. If the system does
not respond (because the firmware has locked up), the circuit generally resets
the system.
Z
zeroize
To zeroize one or more encryption keys is to render them useless by
overwriting the key data with zeros.