Microwave Radio Communications LLC CR2TX2AD Manuale Utente

Pagina di 50
B
 Glossary
B-1
CodeRunner 2 Operator’s Guide/Tech Ref Manual
Glossary
This section describes acronyms and abbreviations used in 
communications, broadcasting, and in MRC Products and 
documentation. 
Table B-1: Useful Terms 
Term
Explanation
16QAM
16-state Quadrature Amplitude Modulation
The signal (video+audio) is imposed onto the 70 MHz 
carrier by varying both the phase and the amplitude 
of the signal while keeping the frequency constant. 
There are 16 possible combinations of phase and 
amplitude that can be used to carry information.
3RU
3 Rack Unit height.
4FSK
4-state Frequency Shift Keying
64QAM
64-state Quadrature Amplitude Modulation
The signal (video+audio) is imposed onto the 70 MHz 
carrier by varying both the phase and the amplitude 
of the signal while keeping the frequency constant. 
There are 64 possible combinations of phase and 
amplitude that can be used to carry information.
A & C
Alarm and Control.
ADPCM
Adaptive Differential Pulse Code Modulation.
AFC
Automatic Frequency Control.
AGC
Automatic Gain Control.
AIS
Alarm Indication Signal (all one’s).
AMI
Alternate Mark Inversion, line code format for traffic 
data.
AVG
Average.
ASI
Asynchronous Serial Interface
A serial communications interface operating at 
270 Mbit/sec., generally used in field news-gathering 
operations. 
Baseband
A composite signal in which video and audio signals 
are combined together, with video occupying 
approximately 0-4.5 MHz and audio modulated onto 
subcarriers in the 5-6MHz range. Also called 
Composite.
B8ZS
Bipolar 8 Zero Substitution, line code format for traffic 
data.
BB
Baseband.
BER
Bit Error Rate.
BiasT
A type of interconnection between the IDU and the 
ODU. In Bias T wiring, IF and DC are combined and 
carried on the coax cable up the ODU; blocking 
circuitry prevents the DC from entering the IDU.
BNC
Bayonet lock coaxial connector.
BPF
Band Pass Filter.
BPS
Bits per second.
BPSK
Binary Phase Shift Keying
CCITT
International Telegraph and Telephone Consultative 
Committee, a telecommunications standardizing 
committee of the ITU.
CNR
Carrier-to-Noise Ratio
COFDM
Coded Orthogonal Frequency Division Multiplexing
Table B-1: Useful Terms  (Continued)