Cisco Series 9900 RF Signal Manager Active Products (NTSC) 安装指南
Glossary
591772 Rev G
105
H
headend system
The part of a CATV system consisting of antennas, video receivers, signal processors,
demodulators, stereo encoders, scramblers, modulators, and other equipment that receives
incoming signals, and then processes and combines them for transmission to subscribers.
HRC
harmonic related coherent frequency plan.
I
IF
intermediate frequency. The common frequency which is mixed with the frequency of a local
oscillator to produce the outgoing radio frequency (RF) signal.
IRC
incremental related coherent frequency plan.
L
luminance
The amount of light intensity in a television picture, perceived by the eye as brightness.
M
MCU
micro-controller unit.
MGC
manual gain control.
modulator
A headend system device that is used to place a baseband signal on a television RF carrier or
channel.
N
NTSC
National Television Standards Committee. A committee that determines video signal
standards for television displays in the United States, Canada, Mexico, and Japan, as well as
other Latin American and Asian countries. The NTSC standard calls for fixed-resolution,
interlaced displays that are updated 30 times per second with a resolution of 525 lines.
R
relay rack
A free-standing, open-air metal rack for mounting electrical equipment. Typically this type of
rack is not enclosed.