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DVB-T introduce the hierarchical modulation conception, the adjacent quadrants
symbol use nonuniform mapping. DVB-T define a parameter factor α, α=1, 2, 4.
The factor α means the distance which a symbol is the closest to the axes X and Y.
When α=1, it means no hierarchical modulation. When α=2 or 4, it means
hierarchical modulation, the Figure 6-41 and Figure 6-42 show the hierarchical
modulation constellation.
In hierarchical modulation, two separate datastreams are modulated onto a single
DVB-T stream. One stream, call the "High Priority" (HP) stream is embedded
within a "Low Priority" (LP) stream.
Figure 6-41 Hierarchical Modulation Constellation-1
Figure 6-42 Hierarchical Modulation Constellation-2
DVB-T/H Echo Pattern
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S7200 TV Signal Analyzer Operation Manual
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