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27 Terminology
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K
/8
K :
The number of carrier waves of the DTT channel
The
8K
mode (6817 carrier waves in the channel, including 6048 carrying useful data)
The
2K
mode (1705 carrier waves in the channel, including 1512 carrying useful data)
For the same purpose, the 8K mode allows the selection of a larger guard interval than the 2K mode, thus a
better resistance to echoes
S
PECTRAL ANALYSIS
:
Method used to highlight the characteristics of the signal. The interest of this analysis is
to visualize the troublemakers as well as the shape of the signal. The spectrum analysis highlights the amplitude
frequency characteristic.
F
REQUENCY BAND
:
Continued portion of the frequency spectrum having made the object of a particular affecta-
tion (telecommunication, television, internal security…)
Example: UHF band
→ 470 to 860 MHz
B
CH
:
Bose Chauhuri Houquenohem
Algorithm used to correct errors in transmissions of digital satellite DVB-S2 signals.
B
ER:
Bit Error Rate
Calculation of the erroneous bits with regard to the number of transmitted bits. BER demonstrates the degrada-
tion of the digital information.
T
V PACKAGE
:
Set of channels spread and marketed by a same operator (TPS, Ca
nal Satellite…)
C
HANNEL:
Assignment of a number to the transmission frequency of an audio video signal. TV channels
receive numbers. Specific to each country.
Example: from 21 to 69 for the UFH band
canal 21 = frequency 471.25 MHz
C
ELL
ID:
Cell identification
Identification of the DVB-T emitter with 4 digits in hexadecimal format, which means 65536 possibilities.
C
/N:
Carrier to Noise ratio
A good C/N ratio helps the quality of the pictures on the TV screen. Ratio in dB.
Caution: You have to take the ratio analysis filter width / channel into account.
C
OFDM:
Coded Orthogonal Frequency Division Multiplex.
Digital coding used for DTT. Its principle is to transmit information via many carrier waves (2K or 8K
mode).
Carrier wave
C/N
Noise
