Keysight EXG and MXG X-Series Signal Generators User’s Guide
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Custom Digital Modulation (Option 431)
Differential Encoding
Entering a value of +1 will cause a 1–state forward transition through the I/Q State Map, as shown
in the following illustration.
As an example, consider the following data/symbol table offset values.
The following I/Q State Map illustrations show all of the possible state
transitions using a particular symbol table offset value. The actual state–
to–state transition would depend upon the state in which the modulation
had started.
Table 16-2
Data
Offset Value
00000000
+1
00000001
–1
00000010
+2
00000011
0
The number of bits per symbol can be expressed using the following
formula. Because the equation is a ceiling function, if the value of x
contains a fraction, x is rounded up to the next whole number.
Where
x
= bits per symbol, and
y
= the number of differential states.
