R&S SMCVB-K163, Руководство пользователя

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DVB-T Configuration and Settings
R&S
®
SMCVB-K163
28 User Manual 1179.0997.02 ─ 02
Constellation
Defines the constellation.
The higher the coding hierarchy, that is the alpha factor, the greater is the distance
between the constellation points of two different quadrants. With identical power out-
put, the high priority path is transmitted more reliably at a higher alpha factor (at the
expense of the low priority path).
"QPSK" Requires "Hierachy > Non-hierarchical".
"16 QAM/64 QAM"
Requires "Hierachy > Alpha 1/2/4".
The high priority path is mapped to the 4 quadrants and therefore
represents a QPSK.
Remote command:
[:SOURce<hw>]:BB:DVBT:CONStel
on page 69
Channel Bandwidth
Selects the channel bandwidth.
The channel bandwidth correlates with the "Used Bandwidth", that is smaller. For the
correlation between the two bandwidths, see
Table 4-2 .
Remote command:
[:SOURce<hw>]:BB:DVBT:CHANnel[:BANDwidth]
on page 69
Used Bandwidth
Defines the used bandwidth.
The used bandwidth correlates with the "Channel Bandwidth", see Table 4-2 . triggers
the used bandwidth value the automatic setting "Channel Bandwidth > Variable".
Table 4-2: Correlation between channel bandwidth and used bandwidth
"Channel bandwidth" "Used bandwidth" Elementary frequency
5 MHz 4.7544643 MHz 40/7 MHz
6 MHz 5.70535717 MHz 48/7 MHz
7 MHz 6.6562500 MHz 56/7 MHz
8 MHz 7.6071429 MHz 64/7 MHz
Variable 1 MHz to 10 MHz
Remote command:
[:SOURce<hw>]:BB:DVBT:USED[:BANDwidth]
on page 71
FFT-Mode
Sets the fast fourier transform (FFT) window to determine the number of carriers per
OFDM symbol.
To find out the number of carriers for a given FFT window, see Table 4-3 .
Coding Settings