The document discusses average symbol energy and constellation diagrams for binary amplitude shift keying (ASK) and phase shift keying (PSK) modulation schemes. It explains that constellation diagrams for binary ASK simply plot the amplitude values for each symbol on the x-axis. It also discusses how to calculate the amplitude values from the given symbol energy. The document then shows constellation diagrams for 8-ary and 16-ary bipolar ASK and describes pulse amplitudes. It introduces binary phase shift keying (BPSK) and M-ary PSK, explaining that M-ary PSK can increase spectral efficiency but cannot be implemented as BPSK.

1. Average Symbol Energy
109

2. Average Energy per bit Vs
Average Energy per Symbol
■ Normally for a communication System Energy per bit is given
■ Difference between Bit duration and Symbol Duration
■ For Binary M-ary Schemes
110

3. Constellation diagram for
Binary ASK
■ Constellation Diagram for ASK: Simply plot the amplitude value
for each pulse (symbol) on the x-axis
0 1 0 1
111

4. Constellation diagram for
Binary ASK
0 1 0 1
112

5. Calculation of the amplitude
values from given Symbol Energy
■ We know that
■ For unipolar or On-Off Keying
■ For bipolar Binary ASK
113

6. Constellation diagram for
Binary ASK
■ Constellation Diagram for ASK simply plot the amplitude value
for each pulse (symbol) on the x-axis
114

7. © Dr. Aimal Khan
Mapper
Pulse
Shaping
Multiplier
M-ary ASK
General Modulator Structure
000...00
000...01
.
.
.
111...11
Antenna
MV
V
V
.
.
.
2
1
115

8. Constellation diagram for 8-ary
Bipolar ASK
000 001 010 011 100 101 110 111
116

9. Constellation diagram for 8-ary
Bipolar ASK
000 001 010 011 100 101 110 111
117

10. Pulse Amplitudes for Bipolar 8-ASK
118

11. Pulse Amplitudes for Bipolar 8-ASK
119

12. Pulse Amplitudes for Bipolar 8-ASK
120

13. Pulse Amplitudes for Bipolar 8-ASK
121

14. Pulse Amplitudes for Bipolar 16-
ary ASK
122

15. Pulse Amplitudes for Bipolar M-ary
ASK
123

16. Pulse Amplitudes for Bipolar M-ary
ASK
124

17. Phase Shift Keying
■ We shift the phase of the carrier signal to represent
digital data.
■ How much shift is possible?
125

18. Binary Phase Shift Keying (BPSK)
© Dr. Aimal Khan 126

19. Binary Phase Shift Keying (BPSK)
■ How much shift is possible?
© Dr. Aimal Khan 127

20. Implementation of BPSK
V V
© Dr. Aimal Khan 128

21. BPSK
0 1
129

22. © Dr. Aimal Khan
M-ary Phase Shift Keying
)
2
2cos(
2
M
i
tf
T
ES csi




Mi
Tt
,...,2,1
,0


■ There can be multiple levels, generally they are equal to
2 power of number of bits.
■ When multiple levels than we must map the bits to
different levels
■ This can increase spectral efficiency
■ Cannot be implemented as BPSK given above, next
slides explain how to implement
)
2
2cos(
M
i
tfVS ci




130