Communication Theory

1
Communication Theory

• Modulation and Channels

2
Communication System

• Todays lecture focus on dashed boxes

3
BFSK Modulator

• Choose between two frequencies

4
BPSK Demodulator

• Mix input with coherent reference

5
BPSK Modulator

• Choose between two phases

6
BPSK Demodulator

• Mix input with coherent reference

7
QPSK Modulator

• Transmit one of 4 symbols
• In-phase and quadrature components

8
QPSK Demodulator

• Evaluate in-phase and quadrature components
  seperately using coherent reference

9
OQPSK Modulator

• Reduce intensity of phase change in QPSK

10
MSK Modulator

• Do away with sharp changes in phase

11
Pulse Shapes

• Combat ISI by replacing square pulses with
  smoother ones