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DIGITAL MODULATION MODE
3-38
64QAM and 256QAM
For these forms of QAM the vector diagram states are similar to 4QAM and 16QAM insofar as
state 0 is always at the top left-hand corner of the diagram, and the intermediate vector values
between 0 and +1 are derived as follows:
1st value above 0 =
)
1
n
(
1
−
where n = the total number of states for the QAM constellation pattern.
subsequent values =
2
×
)
1
n
(
1
−
+ last value
Negative values of I and Q are the same except for the sign.
FSK
The symbol mapping of the signal is as follows:
2FSK
Data Nominal
frequency
1
c frequency deviation
0 carrier
−
frequency deviation
4FSK (Grey coded, normal mapping)
Data Nominal
frequency
10
c frequency deviation
11
c (frequency deviation/3)
01 carrier
−
(frequency deviation/3)
00 carrier
−
frequency deviation
4FSK (Grey coded, inverse mapping)
Data Nominal
frequency
01
c frequency deviation
00
c (frequency deviation/3)
10 carrier
−
(frequency deviation/3)
11 carrier
−
frequency deviation