1
2
3
4
5
BER of BPSK
Figure 6.3 Signal-space diagram for coherent binary PSK system. The waveforms
depicting the transmitted signals s1(t) and s2(t), displayed in the inserts, assume nc  2.
6
Figure 6.3 Signal-space diagram for coherent binary PSK system. The waveforms depicting the
transmitted signals s1(t) and s2(t), displayed in the inserts, assume nc  2.
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8
9
Generation and Detection of Coherent BPSK
Figure 6.4 Block diagrams for (a) binary PSK transmitter and
(b) coherent binary PSK receiver.
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11
Figure 6.5 Power spectra of binary PSK and FSK signals.
12
Figure 6.6 Signal-space diagram of coherent QPSK system.
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14
15
16
17
Generation and Detection of Coherent BPSK
si1
odd
See Table 6.1
even
si2
18
Figure 6.8 Block diagrams of (a) QPSK transmitter and (b) coherent QPSK receiver.
, g(t) denotes the symbol shaping function.
The baseband QPSK PSD
equals the sum of the inphase
and quadrature PSD
19
Figure 6.9 Power spectra of QPSK and MSK signals.
20
Figure 6.7 (a) Input binary sequence. (b) Odd-numbered bits of input sequence and associated
binary PSK wave. (c) Even-numbered bits of input sequence and associated binary PSK wave.
(d) QPSK waveform defined as s(t)  si1f1(t)  si2f2(t).
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Offset QPSK ( Reducing Carrier Amplitude Change)
Figure 6.10 Possible paths for switching between the message points in (a) QPSK
and (b) offset QPSK.
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23
p/4 –shifted QPSK
Two ordinary QPSK constellations
Figure 6.11 Two commonly used signal constellations of QPSK; the arrows
indicate the paths along which the QPSK modulator can change its state.
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25
26
27
28
29
30
Figure 6.14 Illustrating the possibility of phase angles wrapping around the positive real axis.
31
Figure 6.13 Block diagram of the p/4-shifted DQPSK detector.
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33
Figure 6.15 (a) Signal-space diagram for
octaphase-shift keying (i.e., M  8). The
decision boundaries are shown as dashed
lines. (b) Signal-space diagram illustrating
the application of the union bound for
octaphase-shift keying.
34
Figure 6.16 Power spectra of M-ary PSK signals for M  2, 4, 8.35
36
37
38
39
QAM Cross Constellation
M=2n where n is odd (e.g., 5,7,…)
Figure 6.18 Illustrating how a square QAM constellation can be expanded
to form a QAM cross-constellation.
Eb
1 

pe  21 
)
 erfc(
N0
2M 

(6.65)
40
41
BFSK has a two-dimensional signal space
 Eb 
 0 
s1  
 and s 2  

E
 0 
 b 
(6.90), (6.91)
Figure 6.25 Signal-space diagram for binary FSK system. The diagram also includes two 42
inserts showing example waveforms of the two modulated signals s1(t) and s2(t).
43
44
Generation and Detection of Coherent BPSK
Figure 6.26 Block diagrams for (a) binary FSK transmitter and (b) coherent
binary FSK receiver.
45
46
Figure 6.5 Power spectra of binary PSK and FSK signals.
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48
49
50
51
52
53
54
55
56
Figure 6.27 Phase tree.
57
Figure 6.28 Phase trellis; boldfaced path represents the sequence 1101000.
58
59
60
Fig. 6.28
Figure 6.30 (a) Input binary sequence. (b) Waveform of scaled time function s1f1(t). (c)
Waveform of scaled time function s2f2(t). (d) Waveform of the MSK signal s(t) obtained
61
by adding s1f1(t) and s2f2(t) on a bit-by-bit basis.
62
Figure 6.29 Signal-space diagram for MSK system.
The constellation of MSK is similar to that of QPSK
63
64
65
Generation and Detection of MSK Signals
Figure 6.31 Block diagrams for (a) MSK transmitter and (b) coherent MSK receiver.
66
67
68
Let W denote the 3dB baseband bandwidth of te pulse-shaping filter.
log 2 f 2
 H ( f )  exp( 
( ) )
2 W
(6.132)
Figure 6.33 Power spectra of MSK and GMSK signals for varying timebandwidth product. (Reproduced with permission from Dr. Gordon Stüber,
Georgia Tech.)
69
70
PSD of MFSK
f c  f c 1 
1
(Hz)
2T
Figure 6.36 Power spectra of M-ary PSK signals for M  2, 4, 8.
71
72
73
74
75
76
77
78
Figure 6.38 Output of matched filter for a rectangular RF wave: (a) q  0,
and (b) q  180 degrees.
79
80
81
82
83
84
Figure 6.41 Calculation of the conditional probability that l2  l1, given l1.
85
86
87
88
Figure 6.42 Noncoherent receiver for the detection of binary FSK signals.
89
90
91
92
0  t  Tb
Tb  t  2Tb ,
sent s2 (t )
Figure 6.44 Signal-space diagram of received DPSK signal.
93
94
95
96
Figure 6.45 Comparison of the noise performance of different PSK and FSK schemes.
97
Figure 6.46 Signal constellation for (a) M-ary PSK and (b) corresponding M-ary QAM, for M  16.
98