Chapter 4 183
Basic Digital Operation
Differential Encoding
These symbol table offsets will result in one of the transitions, as shown.
When applied to the user-defined default 4QAM I/Q map, starting from the 1st symbol (data 00), the
differential encoding transitions for the data stream (in 2-bit symbols) 0011100001 appear in the following
illustration.
Data Value 00000001
transition 1 state backward
with Symbol Table Offset -1
Data Value 00000010
transition 2 states forward
with Symbol Table Offset +2
Data Value 00000011
no transition
with Symbol Table Offset 0
Data Value 00000000
transition 1 state forward
with Symbol Table Offset +1