Rohde & Schwarz SMIQ02B - Digital Modulation Methods and Coding; PSK and QAM Modulation

SMIQ Digital Modulation
1125.5555.03 E-92.87
2.10.1 Digital Modulation Methods and Coding
The input sequence of modulation symbols d
n
can be subject to different types of coding. I and Q values
are assigned to the coded modulation symbols dc
n
in the functional block MAPPING.
I, ∆
∆∆
∆ F
Q
MAPPING
CODING
modulation
symbols
d
n-2
, d
n-1
, d
n
...
dc
n-2
, dc
n-1
, dc
n
...
Fig. 2-49 Functional blocks Coding and Mapping
2.10.1.1 PSK and QAM Modulation
PSK and QAM modulations can be explained on the basis of a rule of assignment (mapping) according
to which each modulation symbol is represented by I and Q values as shown in the following IQ
constellation diagrams. The constellation diagrams apply if no coding is switched on.
I
Q
0
1 I
Q
0001
10 11
I
Q
0000
0001
00110010
1010 1000
10011011
0101 0111
01100100
1111 1110
11001101
I
Q
1101
00
10
I
Q
0010
11
01
I
Q
001
011
101
111
010
100
110
000
BPSK
QPSK; OQPSK
8PSK, DQPSK
QPSK ISAT
Π/4
ϕ
QPSKIS95
OQPSK IS95
Fig. 2-50 Constellation diagrams of BPSK, QPSK, 8PSK and 16QAM