Vislink HDT-1000, Руководство пользователя и техническое руководство

Страница: 58 / 62

Page 58
HDT-1000 User and Technical Manual
Term Definition
NTSC National Television System Committee
Color television standard used in the US. Provides 525 horizontal lines of
resolution. Not compatible with PAL or SECAM.
OFDM Orthogonal Frequency Division Multiplexing
A modulation scheme that separates the data stream into many data
streams that are slower in speed, which are then transmitted in parallel.
PAL Phase Alternation Line
Color television standard used in many European countries. Provides 625
horizontal lines of resolution. Not compatible with NTSC or SECAM.
PID Program Identification
QAM Quadrature Amplitude Modulation
A method of modulation that expresses data by modulating the amplitude of
two carrier waves.
QPSK Quadrature Phase Shift Keying
The signal [video+audio] is imposed onto the 70 MHz carrier by varying the
phase of the signal while keeping the amplitude and frequency constant.
There are 4 possible values of phase that can be used to carry information.
RSSI Receiver Signal Strength Indicator (relative)
RX Receiver
SCM Single Carrier Modem or Single Carrier Modulation
SDI Serial Digital Interface
A serial communications interface operating at 270 Mbit/sec. SDI can
operate at 1.5 Gbit/sec for HD.
SER Symbol Error Rate
SMPTE Society of Motion Picture and Television Engineers
SNR Signal-to-Noise Ratio
A measure of signal strength and quality that is defined as the ratio of the
amplitude of a signal compared to the amplitude of the background noise.
SNR is typically measured in decibels [dB].
Subcarrier An electromagnetic signal that is used as a medium for placing an
information channel above another information channel.