Phase modulation encodes information by varying the phase of a carrier wave. It includes techniques like phase-shift keying (PSK) where the signal shifts between defined phase states to represent bits, and minimum-shift keying (MSK) which uses continuous phase shifts. Gaussian minimum-shift keying (GMSK) applies Gaussian filtering to MSK signals.

1. PHASE SHIFT
BY
Muhammad Uzair Rasheed
2009-CPE-03
UCE&T BZU MULTAN

2. PHASE MODULATION
• What is phase modulation?
• PSK(Phase shift keying)
• MSK(minimum shift keying)
• GMSK(Gaussian shift keying)

3. What is phase modulation?
• Phase modulation is a form of modulation
that represents information as variation in the
instantaneous phase of a carrier wave.
• Phase modulation(PM) is integral of frequency
modulation(FM)

4. PSK(Phase shift keying)
• In Phase shift keying there are defined states
and points that are used for signaling the data
bits

5. PSK problems
• Receiver cannot know the exact phase of the
transmitted signal to determine whether it is
marked or spaced condition even if the
transmitter and receiver clocks were
accurately linked.
• To overcome this problem making the change
in phase=1 and no phase change=0

6. MSK(minimum shift keying)
• Continuous phase shifting technique

7. GMSK(Gaussian shift keying)
• Special form of MSK