DIGITAL MODULATION MODE
3-36
Phase offset
π
/4 differential QPSK
The phase offset
π
/4 differential QPSK constellation is defined below and shown in Fig. 3-35.
Phase offset
π
/8 differential 8PSK
The offset
π
/8 differential 8PSK constellation is defined below and shown in Fig. 3-36.
QAM
For QAM each data state is mapped to a specific point on the I,Q diagram. There are 4 levels of
QAM allowed: 4QAM, 16QAM, 64QAM and 256QAM.
For each of the following state diagrams each state is labelled with a decimal number. The
decimal number is the condition of the data applied to the AUXILIARY I/O connector e.g. for
16QAM state 14 is obtained with D3 to D0 set to 1110 respectively.
Fig. 3-35 Phase offset
π
/4 differential QPSK
constellation
Data Phase
change
Example
state
changes
00
+45°
P0
→
P1
01
+135°
P0
→
P3
10
-45°
P0
→
P7
11
-135°
P0
→
P5
Fig. 3-36
π
/8 differential 8PSK constellation
Data Phase
change
Example
state
changes
000
+22.5°
P0
→
P1
001
+67.5°
P0
→
P3
100
-22.5°
P0
→
P15
011
+112.5°
P0
→
P5
100
-67.5
P0
→
P13
101
+157.5°
P0
→
P7
110
-112.5°
P0
→
P11
111
-157.5°
P0
→
P9