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Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
9. Bandpass Modulation and DemodulationTechniques
Y. Yoganandam, Runa Kumari, and S. R. Zinka
Department of Electrical & Electronics EngineeringBITS Pilani, Hyderbad Campus
October 21 – 30, 2015
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Outline
1 Introduction
2 Phase Shift Keying (PSK)
3 Differential PSK (DPSK)
4 Frequency Shift Keying (FSK)
5 ASK & APK
6 Summary
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Outline
1 Introduction
2 Phase Shift Keying (PSK)
3 Differential PSK (DPSK)
4 Frequency Shift Keying (FSK)
5 ASK & APK
6 Summary
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Symbols Symbols Symbols Symbols Symbols Symbols Symbols
Symbols Symbols Symbols Symbols Symbols Symbols SymbolsSymbols Symbols Symbols Symbols Symbols Symbols
Symbols Symbols Symbols Symbols Symbols Symbols Symbols
Symbols Symbols Symbols Symbols Symbols Symbols SymbolsSymbols Symbols Symbols Symbols Symbols Symbols
Symbols Symbols Symbols Symbols Symbols Symbols Symbols
Symbols Symbols Symbols Symbols Symbols Symbols SymbolsSymbols Symbols Symbols Symbols Symbols Symbols
Symbols Symbols Symbols Symbols Symbols
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Symbols Symbols Symbols Symbols Symbols Symbols Symbols
Symbols Symbols Symbols Symbols Symbols Symbols SymbolsSymbols Symbols Symbols Symbols Symbols Symbols
Symbols Symbols Symbols Symbols Symbols Symbols Symbols
Symbols Symbols Symbols Symbols Symbols Symbols SymbolsSymbols Symbols Symbols Symbols Symbols Symbols
Symbols Symbols Symbols Symbols Symbols Symbols Symbols
Symbols Symbols Symbols Symbols Symbols Symbols SymbolsSymbols Symbols Symbols Symbols Symbols Symbols
Symbols Symbols Symbols Symbols Symbols
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Analog Modulation Techniques
Carrier Signal:Ac cos (ωct + θ)
Amplitude Modulation:AAM = f (m (t))
Frequency Modulation:ωFM = g (m (t))
Phase Modulation:θPM = h (m (t))
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Analog Modulation Techniques
Carrier Signal:Ac cos (ωct + θ)
Amplitude Modulation:AAM = f (m (t))
Frequency Modulation:ωFM = g (m (t))
Phase Modulation:θPM = h (m (t))
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Analog Modulation Techniques
Carrier Signal:Ac cos (ωct + θ)
Amplitude Modulation:AAM = f (m (t))
Frequency Modulation:ωFM = g (m (t))
Phase Modulation:θPM = h (m (t))
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Analog Modulation Techniques
Carrier Signal:Ac cos (ωct + θ)
Amplitude Modulation:AAM = f (m (t))
Frequency Modulation:ωFM = g (m (t))
Phase Modulation:θPM = h (m (t))
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Analog Modulation Techniques
Carrier Signal:Ac cos (ωct + θ)
Amplitude Modulation:AAM = f (m (t))
Frequency Modulation:ωFM = g (m (t))
Phase Modulation:θPM = h (m (t))
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Digital Modulation Techniques
The main difference between analog and digital modulation techniques ischaracterized by the message signal. In analog case m (t) is an analog signal,
whereas in digital case m (t) is a digital signal.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Digital Modulation Techniques
The main difference between analog and digital modulation techniques ischaracterized by the message signal. In analog case m (t) is an analog signal,
whereas in digital case m (t) is a digital signal.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
A Slight Modified Representation of Carrier Signal
A sinusoidal signal S (t) = A cos ωt can be represented in terms of it’s poweras
S (t) =√
2P cos ωt (1)
because P = A2/2.
The above equation can be further re-written as
S (t) =
√2Es
TScos ωt (2)
because P watts can be replaced by Es joules/TS seconds.��
��
As we have seen in the previous chapter, energy of a received signal is thekey parameter in determining the error performance of the detection process.
That is the reason why we are using the notation√
2Es/TS in this chapter.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
A Slight Modified Representation of Carrier Signal
A sinusoidal signal S (t) = A cos ωt can be represented in terms of it’s poweras
S (t) =√
2P cos ωt (1)
because P = A2/2.
The above equation can be further re-written as
S (t) =
√2Es
TScos ωt (2)
because P watts can be replaced by Es joules/TS seconds.��
��
As we have seen in the previous chapter, energy of a received signal is thekey parameter in determining the error performance of the detection process.
That is the reason why we are using the notation√
2Es/TS in this chapter.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
A Slight Modified Representation of Carrier Signal
A sinusoidal signal S (t) = A cos ωt can be represented in terms of it’s poweras
S (t) =√
2P cos ωt (1)
because P = A2/2.
The above equation can be further re-written as
S (t) =
√2Es
TScos ωt (2)
because P watts can be replaced by Es joules/TS seconds.
��
��
As we have seen in the previous chapter, energy of a received signal is thekey parameter in determining the error performance of the detection process.
That is the reason why we are using the notation√
2Es/TS in this chapter.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
A Slight Modified Representation of Carrier Signal
A sinusoidal signal S (t) = A cos ωt can be represented in terms of it’s poweras
S (t) =√
2P cos ωt (1)
because P = A2/2.
The above equation can be further re-written as
S (t) =
√2Es
TScos ωt (2)
because P watts can be replaced by Es joules/TS seconds.��
��
As we have seen in the previous chapter, energy of a received signal is thekey parameter in determining the error performance of the detection process.
That is the reason why we are using the notation√
2Es/TS in this chapter.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
So, Digital Modulation Techniques are ...
Carrier Signal: √2Es/TS cos (ωct + φ)
Phase Shift Keying:φPSK = φi (t)
Frequency Shift Keying:ωFSK = ωi (t)
Amplitude Shift Keying:EASK = Ei (t)
ASK + PSK:EAPK = Ei (t) & φAPK = φi (t)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
So, Digital Modulation Techniques are ...
Carrier Signal: √2Es/TS cos (ωct + φ)
Phase Shift Keying:φPSK = φi (t)
Frequency Shift Keying:ωFSK = ωi (t)
Amplitude Shift Keying:EASK = Ei (t)
ASK + PSK:EAPK = Ei (t) & φAPK = φi (t)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
So, Digital Modulation Techniques are ...
Carrier Signal: √2Es/TS cos (ωct + φ)
Phase Shift Keying:φPSK = φi (t)
Frequency Shift Keying:ωFSK = ωi (t)
Amplitude Shift Keying:EASK = Ei (t)
ASK + PSK:EAPK = Ei (t) & φAPK = φi (t)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
So, Digital Modulation Techniques are ...
Carrier Signal: √2Es/TS cos (ωct + φ)
Phase Shift Keying:φPSK = φi (t)
Frequency Shift Keying:ωFSK = ωi (t)
Amplitude Shift Keying:EASK = Ei (t)
ASK + PSK:EAPK = Ei (t) & φAPK = φi (t)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
So, Digital Modulation Techniques are ...
Carrier Signal: √2Es/TS cos (ωct + φ)
Phase Shift Keying:φPSK = φi (t)
Frequency Shift Keying:ωFSK = ωi (t)
Amplitude Shift Keying:EASK = Ei (t)
ASK + PSK:EAPK = Ei (t) & φAPK = φi (t)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
So, Digital Modulation Techniques are ...
Carrier Signal: √2Es/TS cos (ωct + φ)
Phase Shift Keying:φPSK = φi (t)
Frequency Shift Keying:ωFSK = ωi (t)
Amplitude Shift Keying:EASK = Ei (t)
ASK + PSK:EAPK = Ei (t) & φAPK = φi (t)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Digital Modulation Techniques – Examples
ASK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Digital Modulation Techniques – Examples
ASK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Digital Modulation Techniques – Examples
ASK
PSK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Digital Modulation Techniques – Examples
ASK
PSK
FSK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Digital Modulation Techniques – Examples
ASK
PSK
FSK
ASK/PSK (APK)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bits vs Symbols
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bits vs Symbols
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bits vs Symbols
BitwiseASK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bits vs Symbols
BitwiseASK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bits vs Symbols
BitwiseASK
SymbolwiseASK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Why Digital Modulation?
Digital modulation is a process of translating the symbols into waveforms.
In baseband modulation, the waveforms are shaped pulses.
We can not send baseband signals over wireless. We need to translate thesignals to higher frequencies for ease of transmission.
Higher frequencies give us the benefit of multiplexing multiple channelsaround the same carrier.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Why Digital Modulation?
Digital modulation is a process of translating the symbols into waveforms.
In baseband modulation, the waveforms are shaped pulses.
We can not send baseband signals over wireless. We need to translate thesignals to higher frequencies for ease of transmission.
Higher frequencies give us the benefit of multiplexing multiple channelsaround the same carrier.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Why Digital Modulation?
Digital modulation is a process of translating the symbols into waveforms.
In baseband modulation, the waveforms are shaped pulses.
We can not send baseband signals over wireless. We need to translate thesignals to higher frequencies for ease of transmission.
Higher frequencies give us the benefit of multiplexing multiple channelsaround the same carrier.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Why Digital Modulation?
Digital modulation is a process of translating the symbols into waveforms.
In baseband modulation, the waveforms are shaped pulses.
We can not send baseband signals over wireless. We need to translate thesignals to higher frequencies for ease of transmission.
Higher frequencies give us the benefit of multiplexing multiple channelsaround the same carrier.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Why Digital Modulation?
Digital modulation is a process of translating the symbols into waveforms.
In baseband modulation, the waveforms are shaped pulses.
We can not send baseband signals over wireless. We need to translate thesignals to higher frequencies for ease of transmission.
Higher frequencies give us the benefit of multiplexing multiple channelsaround the same carrier.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Symbol Energy vs bit Energy
Es = nEb (3)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Symbol Energy vs bit Energy
Es = nEb (3)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of ASK
Amplitude shift keyingor
On-off keying
0 1 0 1 1 0 1 0 1 1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of ASK
Amplitude shift keyingor
On-off keying
0 1 0 1 1 0 1 0 1 1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of ASK
Amplitude shift keyingor
On-off keying
0 1 0 1 1 0 1 0 1 1
Carrier
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of ASK
Amplitude shift keyingor
On-off keying
0 1 0 1 1 0 1 0 1 1
Carrier
On-offline-coded
data
1 V
0 V
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of ASK
Amplitude shift keyingor
On-off keying
0 1 0 1 1 0 1 0 1 1
Carrier
On-offline-coded
data
+1 V
0 V
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of ASK
Amplitude shift keyingor
On-off keying
0 1 0 1 1 0 1 0 1 1
Carrier
On-offline-coded
data
+1 V
0 V
2π
Tb
4π
Tb
6π
Tb
8π
Tb
2π
Tb
4π
Tb
6π
Tb
8π
Tb
0ω
On-offLine-codespectrum
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of ASK
Amplitude shift keyingor
On-off keying
0 1 0 1 1 0 1 0 1 1
Carrier
On-offline-coded
data
+1 V
0 V
2π
Tb
4π
Tb
6π
Tb
8π
Tb
2π
Tb
4π
Tb
6π
Tb
8π
Tb
0ω
On-offLine-codespectrum
ω
ASKspectrum
-ω0 +ω0
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of PSK
Phase shift keying
0 1 0 1 1 0 1 0 1 1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of PSK
Phase shift keying
0 1 0 1 1 0 1 0 1 1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of PSK
Phase shift keying
0 1 0 1 1 0 1 0 1 1
Carrier
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of PSK
Phase shift keying
0 1 0 1 1 0 1 0 1 1
Carrier
NRZ-Lline-coded
data
1 V
-1 V
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of PSK
Phase shift keying
0 1 0 1 1 0 1 0 1 1
Carrier
NRZ-Lline-coded
data
+1 V
-1 V
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of PSK
Phase shift keying
0 1 0 1 1 0 1 0 1 1
Carrier
NRZ-Lline-coded
data
+1 V
-1 V
2π
Tb
4π
Tb
6π
Tb
8π
Tb
2π
Tb
4π
Tb
6π
Tb
8π
Tb
0ω
NRZ-LLine-codespectrum
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of PSK
Phase shift keying
0 1 0 1 1 0 1 0 1 1
Carrier
NRZ-Lline-coded
data
+1 V
-1 V
2π
Tb
4π
Tb
6π
Tb
8π
Tb
2π
Tb
4π
Tb
6π
Tb
8π
Tb
0ω
NRZ-LLine-codespectrum
ω
PSKspectrum
-ω0 +ω0
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of FSK
Frequency shift keying
0 1 0 1 1 0 1 0 1 1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of FSK
Frequency shift keying
0 1 0 1 1 0 1 0 1 1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of FSK
Frequency shift keying
0 1 0 1 1 0 1 0 1 1
ASK 1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of FSK
Frequency shift keying
0 1 0 1 1 0 1 0 1 1
ASK 1
ASK 2
1 V
-1 V
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of FSK
Frequency shift keying
0 1 0 1 1 0 1 0 1 1
ASK 1
ASK 2
+
1 V
-1 V
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of FSK
2π
Tb
4π
Tb
6π
Tb
8π
Tb
2π
Tb
4π
Tb
6π
Tb
8π
Tb
0ω
On-offLine-codespectrum
Frequency shift keying
0 1 0 1 1 0 1 0 1 1
ASK 1
ASK 2
+
1 V
-1 V
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectral Properties of FSK
2π
Tb
4π
Tb
6π
Tb
8π
Tb
2π
Tb
4π
Tb
6π
Tb
8π
Tb
0ω
On-offLine-codespectrum
ω
FSKspectrum
-ω2 +ω1
Frequency shift keying
0 1 0 1 1 0 1 0 1 1
ASK 1
ASK 2
+
1 V
-1 V
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Outline
1 Introduction
2 Phase Shift Keying (PSK)
3 Differential PSK (DPSK)
4 Frequency Shift Keying (FSK)
5 ASK & APK
6 Summary
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Phase Shift Keying (MPSK)
If a digital signal can be completely represented by M different levels, thenthose M levels can be converted into M symbols (or alphabets). Each of theseM symbols can be associated with a unique phase φi, where i = 1, 2, · · · , M.Since 0 ≤ φ ≤ 2π, if we distribute these phases uniformly,
φi =2πiM
, i = 1, 2, · · · , M. (4)
So, the modulated PSK signal is given by
Si (t) =
√2Es
TSsin(
ω0t +2πiM
), i = 1, 2, · · · , M
=
√2Es
TS
[sin (ω0t) cos
(2πiM
)+ cos (ω0t) sin
(2πiM
)]=√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], (5)
where ψ1 (t) =√
2/TS sin ω0t and ψ2 (t) =√
2/TS cos ω0t.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Phase Shift Keying (MPSK)If a digital signal can be completely represented by M different levels, thenthose M levels can be converted into M symbols (or alphabets).
Each of theseM symbols can be associated with a unique phase φi, where i = 1, 2, · · · , M.Since 0 ≤ φ ≤ 2π, if we distribute these phases uniformly,
φi =2πiM
, i = 1, 2, · · · , M. (4)
So, the modulated PSK signal is given by
Si (t) =
√2Es
TSsin(
ω0t +2πiM
), i = 1, 2, · · · , M
=
√2Es
TS
[sin (ω0t) cos
(2πiM
)+ cos (ω0t) sin
(2πiM
)]=√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], (5)
where ψ1 (t) =√
2/TS sin ω0t and ψ2 (t) =√
2/TS cos ω0t.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Phase Shift Keying (MPSK)If a digital signal can be completely represented by M different levels, thenthose M levels can be converted into M symbols (or alphabets). Each of theseM symbols can be associated with a unique phase φi, where i = 1, 2, · · · , M.
Since 0 ≤ φ ≤ 2π, if we distribute these phases uniformly,
φi =2πiM
, i = 1, 2, · · · , M. (4)
So, the modulated PSK signal is given by
Si (t) =
√2Es
TSsin(
ω0t +2πiM
), i = 1, 2, · · · , M
=
√2Es
TS
[sin (ω0t) cos
(2πiM
)+ cos (ω0t) sin
(2πiM
)]=√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], (5)
where ψ1 (t) =√
2/TS sin ω0t and ψ2 (t) =√
2/TS cos ω0t.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Phase Shift Keying (MPSK)If a digital signal can be completely represented by M different levels, thenthose M levels can be converted into M symbols (or alphabets). Each of theseM symbols can be associated with a unique phase φi, where i = 1, 2, · · · , M.Since 0 ≤ φ ≤ 2π, if we distribute these phases uniformly,
φi =2πiM
, i = 1, 2, · · · , M. (4)
So, the modulated PSK signal is given by
Si (t) =
√2Es
TSsin(
ω0t +2πiM
), i = 1, 2, · · · , M
=
√2Es
TS
[sin (ω0t) cos
(2πiM
)+ cos (ω0t) sin
(2πiM
)]=√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], (5)
where ψ1 (t) =√
2/TS sin ω0t and ψ2 (t) =√
2/TS cos ω0t.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Phase Shift Keying (MPSK)If a digital signal can be completely represented by M different levels, thenthose M levels can be converted into M symbols (or alphabets). Each of theseM symbols can be associated with a unique phase φi, where i = 1, 2, · · · , M.Since 0 ≤ φ ≤ 2π, if we distribute these phases uniformly,
φi =2πiM
, i = 1, 2, · · · , M. (4)
So, the modulated PSK signal is given by
Si (t) =
√2Es
TSsin(
ω0t +2πiM
), i = 1, 2, · · · , M
=
√2Es
TS
[sin (ω0t) cos
(2πiM
)+ cos (ω0t) sin
(2πiM
)]=√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], (5)
where ψ1 (t) =√
2/TS sin ω0t and ψ2 (t) =√
2/TS cos ω0t.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Phase Shift Keying (MPSK)If a digital signal can be completely represented by M different levels, thenthose M levels can be converted into M symbols (or alphabets). Each of theseM symbols can be associated with a unique phase φi, where i = 1, 2, · · · , M.Since 0 ≤ φ ≤ 2π, if we distribute these phases uniformly,
φi =2πiM
, i = 1, 2, · · · , M. (4)
So, the modulated PSK signal is given by
Si (t) =
√2Es
TSsin(
ω0t +2πiM
), i = 1, 2, · · · , M
=
√2Es
TS
[sin (ω0t) cos
(2πiM
)+ cos (ω0t) sin
(2πiM
)]
=√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], (5)
where ψ1 (t) =√
2/TS sin ω0t and ψ2 (t) =√
2/TS cos ω0t.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Phase Shift Keying (MPSK)If a digital signal can be completely represented by M different levels, thenthose M levels can be converted into M symbols (or alphabets). Each of theseM symbols can be associated with a unique phase φi, where i = 1, 2, · · · , M.Since 0 ≤ φ ≤ 2π, if we distribute these phases uniformly,
φi =2πiM
, i = 1, 2, · · · , M. (4)
So, the modulated PSK signal is given by
Si (t) =
√2Es
TSsin(
ω0t +2πiM
), i = 1, 2, · · · , M
=
√2Es
TS
[sin (ω0t) cos
(2πiM
)+ cos (ω0t) sin
(2πiM
)]=√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], (5)
where ψ1 (t) =√
2/TS sin ω0t and ψ2 (t) =√
2/TS cos ω0t.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Modulation Mechanism
Digitaldata(or)
stream
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Modulation Mechanism
Digitaldata(or)
stream
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Modulation Mechanism
Digitaldata(or)
stream
Pickone symbol
at a time
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Modulation Mechanism
Digitaldata(or)
stream
Identifythe
symbol,i.e.,
i
Pickone symbol
at a time
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Modulation Mechanism
Digitaldata(or)
stream
Identifythe
symbol,i.e.,
i
Pickone symbol
at a time
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Modulation Mechanism
π/2
Digitaldata(or)
stream
Identifythe
symbol,i.e.,
i
Pickone symbol
at a time
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Modulation Mechanism
Σ
π/2
Digitaldata(or)
stream
Identifythe
symbol,i.e.,
i
Pickone symbol
at a timeSi (t)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Signal Space Representation of Si (t)
Si (t)
{ {
Si (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
]
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Signal Space Representation of Si (t)
Si (t)
{ {
Si (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
]
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Signal Space Representation of Si (t)
Si (t)
{ {Si (t) =
√Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
]
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Constellation Diagram
S1(t)S2(t)
S4(t)S3(t)
Si (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
]
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Binary PSK (BPSK/2PSK)
S1(t) S2(t) M = 2
1 0 1 1 0 1 1 1 0 0
(i = 1) (i = 2)
S1(t) S2(t)
Si (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], M = 2 for BPSK
S1 (t) = −√
Esψ1 (t) = −√
2Es/TS sin ω0t (6)
S2 (t) = +√
Esψ1 (t) = +√
2Es/TS sin ω0t (7)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Binary PSK (BPSK/2PSK)
S1(t) S2(t) M = 2
1 0 1 1 0 1 1 1 0 0
(i = 1) (i = 2)
S1(t) S2(t)
Si (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], M = 2 for BPSK
S1 (t) = −√
Esψ1 (t) = −√
2Es/TS sin ω0t (6)
S2 (t) = +√
Esψ1 (t) = +√
2Es/TS sin ω0t (7)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Binary PSK (BPSK/2PSK)
S1(t) S2(t) M = 2
1 0 1 1 0 1 1 1 0 0
(i = 1) (i = 2)
S1(t) S2(t)
Si (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], M = 2 for BPSK
S1 (t) = −√
Esψ1 (t) = −√
2Es/TS sin ω0t (6)
S2 (t) = +√
Esψ1 (t) = +√
2Es/TS sin ω0t (7)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Binary PSK (BPSK/2PSK)
S1(t) S2(t) M = 2
1 0 1 1 0 1 1 1 0 0
(i = 1) (i = 2)
S1(t) S2(t)
Si (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], M = 2 for BPSK
S1 (t) = −√
Esψ1 (t) = −√
2Es/TS sin ω0t (6)
S2 (t) = +√
Esψ1 (t) = +√
2Es/TS sin ω0t (7)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Binary PSK (BPSK/2PSK)
S1(t) S2(t) M = 2
1 0 1 1 0 1 1 1 0 0
(i = 1) (i = 2)
S1(t) S2(t)
Si (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], M = 2 for BPSK
S1 (t) = −√
Esψ1 (t) = −√
2Es/TS sin ω0t (6)
S2 (t) = +√
Esψ1 (t) = +√
2Es/TS sin ω0t (7)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Quadri PSK (QPSK)
00(i = 1)
01(i = 2)
10(i = 3)
11(i = 4)
S1(t)
S2(t)
S3(t)
S4(t)M = 4
S1(t) S2(t) S4(t)S3(t)
Si (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], M = 4 for QPSK (8)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Quadri PSK (QPSK)
00(i = 1)
01(i = 2)
10(i = 3)
11(i = 4)
S1(t)
S2(t)
S3(t)
S4(t)M = 4
S1(t) S2(t) S4(t)S3(t)
Si (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], M = 4 for QPSK (8)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Quadri PSK (QPSK)
00(i = 1)
01(i = 2)
10(i = 3)
11(i = 4)
S1(t)
S2(t)
S3(t)
S4(t)M = 4
S1(t) S2(t) S4(t)S3(t)
Si (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
], M = 4 for QPSK (8)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
8PSK
The constellations become denser as M increases.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
8PSK
The constellations become denser as M increases.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
8PSK
The constellations become denser as M increases.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
The demodulator is expected to give back the symbol.
Since the Symbol has been encoded into phase of the carrier, we need toextract the phase of the received carrier, during a particular symbol duration
and drop the carrier.
Since phase extraction is involved, the process has to be a coherent one.
Further, the received signal is noisy:
r (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
]+ n (t) (9)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
The demodulator is expected to give back the symbol.
Since the Symbol has been encoded into phase of the carrier, we need toextract the phase of the received carrier, during a particular symbol duration
and drop the carrier.
Since phase extraction is involved, the process has to be a coherent one.
Further, the received signal is noisy:
r (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
]+ n (t) (9)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
The demodulator is expected to give back the symbol.
Since the Symbol has been encoded into phase of the carrier, we need toextract the phase of the received carrier, during a particular symbol duration
and drop the carrier.
Since phase extraction is involved, the process has to be a coherent one.
Further, the received signal is noisy:
r (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
]+ n (t) (9)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
The demodulator is expected to give back the symbol.
Since the Symbol has been encoded into phase of the carrier, we need toextract the phase of the received carrier, during a particular symbol duration
and drop the carrier.
Since phase extraction is involved, the process has to be a coherent one.
Further, the received signal is noisy:
r (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
]+ n (t) (9)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
The demodulator is expected to give back the symbol.
Since the Symbol has been encoded into phase of the carrier, we need toextract the phase of the received carrier, during a particular symbol duration
and drop the carrier.
Since phase extraction is involved, the process has to be a coherent one.
Further, the received signal is noisy:
r (t) =√
Es
[cos
(2πiM
)ψ1 (t) + sin
(2πiM
)ψ2 (t)
]+ n (t) (9)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
Apply minimum distance criterion with respect to the pre determined set.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
Apply minimum distance criterion with respect to the pre determined set.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
Apply minimum distance criterion with respect to the pre determined set.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
Apply minimum distance criterion with respect to the pre determined set.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
Apply minimum distance criterion with respect to the pre-determined set.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
Apply minimum distance criterion with respect to the pre-determined set.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
r(t)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
r(t)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
∫0
Ts
r(t)
∫0
Ts
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
∫0
Ts
r(t)
∫0
Ts
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
∫0
Ts
r(t)
∫0
Ts
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
∫0
Ts
r(t)
∫0
Ts
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
φ = tan−1 YX
(10)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Coherent Demodulation
φ = tan−1 YX
(10)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BPSK – Coherent Demodulation
∫0
Ts
r(t)
∫0
Ts
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BPSK – Coherent Demodulation
∫0
Ts
r(t)
∫0
Ts
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BPSK – Coherent Demodulation
∫0
Ts
r(t)
∫0
Ts
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BPSK – Coherent Demodulation
S1(t) S2(t)
S1 (t) = −√
Esψ1 (t) = −√
2Es/TS sin ω0t
S2 (t) = +√
Esψ1 (t) = +√
2Es/TS sin ω0t
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BPSK – Coherent Demodulation
S1(t) S2(t)
S1 (t) = −√
Esψ1 (t) = −√
2Es/TS sin ω0t
S2 (t) = +√
Esψ1 (t) = +√
2Es/TS sin ω0t
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BPSK – Coherent Demodulation
S1(t) S2(t)
S1 (t) = −√
Esψ1 (t) = −√
2Es/TS sin ω0t
S2 (t) = +√
Esψ1 (t) = +√
2Es/TS sin ω0t
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BPSK – Coherent Demodulation
S1(t) S2(t)
S1 (t) = −√
Esψ1 (t) = −√
2Es/TS sin ω0t
S2 (t) = +√
Esψ1 (t) = +√
2Es/TS sin ω0t
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BPSK – Coherent Demodulation
∫0
Tsr(t) X γ0><
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BPSK – Coherent Demodulation
∫0
Tsr(t) X γ0><
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BPSK – Probability of Symbol (Bit) Error
S1(t) S2(t)
The threshold γ0 is 0, and decision rule is to declare S1 or S2 based on thethreshold crossing. This is similar to NRZ binary baseband problem.
So, for AWGN with one sided spectral density of N0/2 Watts/Hz, probabilityof symbol error is given as
PBPSKS = Q
(√2Es
N0
). (11)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BPSK – Probability of Symbol (Bit) Error
S1(t) S2(t)
The threshold γ0 is 0, and decision rule is to declare S1 or S2 based on thethreshold crossing. This is similar to NRZ binary baseband problem.
So, for AWGN with one sided spectral density of N0/2 Watts/Hz, probabilityof symbol error is given as
PBPSKS = Q
(√2Es
N0
). (11)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BPSK – Probability of Symbol (Bit) Error
S1(t) S2(t)
The threshold γ0 is 0, and decision rule is to declare S1 or S2 based on thethreshold crossing.
This is similar to NRZ binary baseband problem.
So, for AWGN with one sided spectral density of N0/2 Watts/Hz, probabilityof symbol error is given as
PBPSKS = Q
(√2Es
N0
). (11)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BPSK – Probability of Symbol (Bit) Error
S1(t) S2(t)
The threshold γ0 is 0, and decision rule is to declare S1 or S2 based on thethreshold crossing. This is similar to NRZ binary baseband problem.
So, for AWGN with one sided spectral density of N0/2 Watts/Hz, probabilityof symbol error is given as
PBPSKS = Q
(√2Es
N0
). (11)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BPSK – Probability of Symbol (Bit) Error
S1(t) S2(t)
The threshold γ0 is 0, and decision rule is to declare S1 or S2 based on thethreshold crossing. This is similar to NRZ binary baseband problem.
So, for AWGN with one sided spectral density of N0/2 Watts/Hz, probabilityof symbol error is given as
PBPSKS = Q
(√2Es
N0
). (11)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
QPSK – Probability of Symbol Error
Probability of symbol error is given (proof will be provided later) as
PQPSKS = 2Q
(√Es
N0
)−[
Q
(√Es
N0
)]2
≈ 2Q
(√Es
N0
), for large SNR.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
QPSK – Probability of Symbol Error
Probability of symbol error is given (proof will be provided later) as
PQPSKS = 2Q
(√Es
N0
)−[
Q
(√Es
N0
)]2
≈ 2Q
(√Es
N0
), for large SNR.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
QPSK – Probability of Symbol Error
Probability of symbol error is given (proof will be provided later) as
PQPSKS = 2Q
(√Es
N0
)−[
Q
(√Es
N0
)]2
≈ 2Q
(√Es
N0
), for large SNR.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
QPSK – Probability of Symbol Error
Probability of symbol error is given (proof will be provided later) as
PQPSKS = 2Q
(√Es
N0
)−[
Q
(√Es
N0
)]2
≈ 2Q
(√Es
N0
), for large SNR.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Probability of Symbol Error
For MPSK, probability of symbol error is given as
PMPSKS ≈ 2Q
(dmin√
2N0
)= 2Q
(√2Es
N0sin
π
M
), for large SNR.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Probability of Symbol Error
For MPSK, probability of symbol error is given as
PMPSKS ≈ 2Q
(dmin√
2N0
)= 2Q
(√2Es
N0sin
π
M
), for large SNR.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Probability of Symbol Error
For MPSK, probability of symbol error is given as
PMPSKS ≈ 2Q
(dmin√
2N0
)= 2Q
(√2Es
N0sin
π
M
), for large SNR.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Symbol Error vs Bit Error
00
11
10
01
Q
I
000
110100
010
Q
I
001
111
101
011
An error in phase might cause symbol error ... and one symbol error cancause atmost n bit errors.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Symbol Error vs Bit Error
00
11
10
01
Q
I
000
110100
010
Q
I
001
111
101
011
An error in phase might cause symbol error ... and one symbol error cancause atmost n bit errors.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Symbol Error vs Bit Error
00
11
10
01
Q
I
000
110100
010
Q
I
001
111
101
011
An error in phase might cause symbol error ...
and one symbol error cancause atmost n bit errors.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Symbol Error vs Bit Error
00
11
10
01
Q
I
000
110100
010
Q
I
001
111
101
011
An error in phase might cause symbol error ... and one symbol error cancause atmost n bit errors.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Symbol Mapping using Gray Code
01
11
10
00
Q
I
110
101000
011
Q
I
010
111
100
001
An error in phase might cause symbol error ... and Gray coding makes surethat symbols corresponding to adjacent phases change only one bit at a time.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Symbol Mapping using Gray Code
01
11
10
00
Q
I
110
101000
011
Q
I
010
111
100
001
An error in phase might cause symbol error ... and Gray coding makes surethat symbols corresponding to adjacent phases change only one bit at a time.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Symbol Mapping using Gray Code
01
11
10
00
Q
I
110
101000
011
Q
I
010
111
100
001
An error in phase might cause symbol error ...
and Gray coding makes surethat symbols corresponding to adjacent phases change only one bit at a time.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Symbol Mapping using Gray Code
01
11
10
00
Q
I
110
101000
011
Q
I
010
111
100
001
An error in phase might cause symbol error ... and Gray coding makes surethat symbols corresponding to adjacent phases change only one bit at a time.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
PS vs PB using Gray Code
01
11
10
00
Q
I
110
101000
011
Q
I
010
111
100
001
PB ≈PSk
=PS
log2 M(for PS � 1) (12)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
PS vs PB using Gray Code
01
11
10
00
Q
I
110
101000
011
Q
I
010
111
100
001
PB ≈PSk
=PS
log2 M(for PS � 1) (12)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
PS vs PB using Gray Code
01
11
10
00
Q
I
110
101000
011
Q
I
010
111
100
001
PB ≈PSk
=PS
log2 M(for PS � 1) (12)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of Gray Code
01
n=1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of Gray Code
01
n=1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of Gray Code
0110
01
n=1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of Gray Code
0110
01
0001
n=2n=1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of Gray Code
0110
01
00011110
n=2n=1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of Gray Code
0110
00011110
01
00011110
00011110
n=2n=1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of Gray Code
0110
00011110
01
00011110
00011110
000001011010
n=2n=3
n=1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of Gray Code
0110
00011110
01
00011110
00011110
000001011010
100101111110
n=2n=3
n=1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of QPSK using BPSK
10 11
0100
Q
I
Sin + Cos
- Sin + Cos- Sin - Cos
Sin - Cos
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of QPSK using BPSK
10 11
0100
Q
I
Sin + Cos
- Sin + Cos- Sin - Cos
Sin - Cos
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of QPSK using BPSK
10 11
0100
Q
I
Sin + Cos
- Sin + Cos- Sin - Cos
Sin - Cos
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of QPSK using BPSK
+1 TS = 2Tb
10 11
0100
Q
I
Sin + Cos
- Sin + Cos- Sin - Cos
Sin - Cos
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of QPSK using BPSK
+1 TS = 2Tb
10 11
0100
Q
I
Sin + Cos
- Sin + Cos- Sin - Cos
Sin - Cos
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of QPSK using BPSK
+1
-1
TS = 2Tb
TS = 2Tb
10 11
0100
Q
I
Sin + Cos
- Sin + Cos- Sin - Cos
Sin - Cos
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of QPSK using BPSK
+1
-1
TS = 2Tb
TS = 2Tb
10 11
0100
Q
I
Sin + Cos
- Sin + Cos- Sin - Cos
Sin - Cos
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generation of QPSK using BPSK
+1
-1
TS = 2Tb
TS = 2Tb
10 11
0100
Q
I
Sin + Cos
- Sin + Cos- Sin - Cos
Sin - Cos
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bit & Symbol Error Rates – BPSK vs QPSK
Although QPSK can be viewed as a quaternary modulation, it is easier to seeit as two independently modulated quadrature carriers. So, BPSK demod-ulation can be applied on both the carriers independantly. As a result, theprobability of bit-error for QPSK is the same as for BPSK:
PBPSK/QPSKB = Q
(√2EbN0
). (13)
Since we know the probability of bit-error, we can calculate probability of sym-bol error as
PQPSKS = 1−
(1− PBPSK
B
)2
= 2Q
(√2EbN0
)−[
Q
(√2EbN0
)]2
≈ 2Q
(√2EbN0
)= 2Q
(√2EbN0
). (14)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bit & Symbol Error Rates – BPSK vs QPSK
Although QPSK can be viewed as a quaternary modulation, it is easier to seeit as two independently modulated quadrature carriers.
So, BPSK demod-ulation can be applied on both the carriers independantly. As a result, theprobability of bit-error for QPSK is the same as for BPSK:
PBPSK/QPSKB = Q
(√2EbN0
). (13)
Since we know the probability of bit-error, we can calculate probability of sym-bol error as
PQPSKS = 1−
(1− PBPSK
B
)2
= 2Q
(√2EbN0
)−[
Q
(√2EbN0
)]2
≈ 2Q
(√2EbN0
)= 2Q
(√2EbN0
). (14)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bit & Symbol Error Rates – BPSK vs QPSK
Although QPSK can be viewed as a quaternary modulation, it is easier to seeit as two independently modulated quadrature carriers. So, BPSK demod-ulation can be applied on both the carriers independantly.
As a result, theprobability of bit-error for QPSK is the same as for BPSK:
PBPSK/QPSKB = Q
(√2EbN0
). (13)
Since we know the probability of bit-error, we can calculate probability of sym-bol error as
PQPSKS = 1−
(1− PBPSK
B
)2
= 2Q
(√2EbN0
)−[
Q
(√2EbN0
)]2
≈ 2Q
(√2EbN0
)= 2Q
(√2EbN0
). (14)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bit & Symbol Error Rates – BPSK vs QPSK
Although QPSK can be viewed as a quaternary modulation, it is easier to seeit as two independently modulated quadrature carriers. So, BPSK demod-ulation can be applied on both the carriers independantly. As a result, theprobability of bit-error for QPSK is the same as for BPSK:
PBPSK/QPSKB = Q
(√2EbN0
). (13)
Since we know the probability of bit-error, we can calculate probability of sym-bol error as
PQPSKS = 1−
(1− PBPSK
B
)2
= 2Q
(√2EbN0
)−[
Q
(√2EbN0
)]2
≈ 2Q
(√2EbN0
)= 2Q
(√2EbN0
). (14)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bit & Symbol Error Rates – BPSK vs QPSK
Although QPSK can be viewed as a quaternary modulation, it is easier to seeit as two independently modulated quadrature carriers. So, BPSK demod-ulation can be applied on both the carriers independantly. As a result, theprobability of bit-error for QPSK is the same as for BPSK:
PBPSK/QPSKB = Q
(√2EbN0
). (13)
Since we know the probability of bit-error, we can calculate probability of sym-bol error as
PQPSKS = 1−
(1− PBPSK
B
)2
= 2Q
(√2EbN0
)−[
Q
(√2EbN0
)]2
≈ 2Q
(√2EbN0
)= 2Q
(√2EbN0
). (14)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bit & Symbol Error Rates – BPSK vs QPSK
Although QPSK can be viewed as a quaternary modulation, it is easier to seeit as two independently modulated quadrature carriers. So, BPSK demod-ulation can be applied on both the carriers independantly. As a result, theprobability of bit-error for QPSK is the same as for BPSK:
PBPSK/QPSKB = Q
(√2EbN0
). (13)
Since we know the probability of bit-error, we can calculate probability of sym-bol error as
PQPSKS = 1−
(1− PBPSK
B
)2
= 2Q
(√2EbN0
)−[
Q
(√2EbN0
)]2
≈ 2Q
(√2EbN0
)= 2Q
(√2EbN0
). (14)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bit & Symbol Error Rates – BPSK vs QPSK
Although QPSK can be viewed as a quaternary modulation, it is easier to seeit as two independently modulated quadrature carriers. So, BPSK demod-ulation can be applied on both the carriers independantly. As a result, theprobability of bit-error for QPSK is the same as for BPSK:
PBPSK/QPSKB = Q
(√2EbN0
). (13)
Since we know the probability of bit-error, we can calculate probability of sym-bol error as
PQPSKS = 1−
(1− PBPSK
B
)2
= 2Q
(√2EbN0
)−[
Q
(√2EbN0
)]2
≈ 2Q
(√2EbN0
)= 2Q
(√2EbN0
). (14)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bit & Symbol Error Rates – BPSK vs QPSK
Although QPSK can be viewed as a quaternary modulation, it is easier to seeit as two independently modulated quadrature carriers. So, BPSK demod-ulation can be applied on both the carriers independantly. As a result, theprobability of bit-error for QPSK is the same as for BPSK:
PBPSK/QPSKB = Q
(√2EbN0
). (13)
Since we know the probability of bit-error, we can calculate probability of sym-bol error as
PQPSKS = 1−
(1− PBPSK
B
)2
= 2Q
(√2EbN0
)−[
Q
(√2EbN0
)]2
≈ 2Q
(√2EbN0
)= 2Q
(√2EbN0
). (14)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK - PS and PB
Eb/N0 (dB)
Sym
bol e
rror
pro
babi
lity,
PS
Bit e
rror
pro
babi
lity,
PB
Eb/N0 (dB)
M = 2M = 4
M = 8
M = 16
M = 32
M = 64k = 1, 2
k = 3 k = 4 k = 5 k = 6
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK - PS and PB
Eb/N0 (dB)
Sym
bol e
rror
pro
babi
lity,
PS
Bit e
rror
pro
babi
lity,
PB
Eb/N0 (dB)
M = 2M = 4
M = 8
M = 16
M = 32
M = 64k = 1, 2
k = 3 k = 4 k = 5 k = 6
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bandwidth & Bandwidth Efficiency of MPSK
For MPSK, the baseband PSD is given by
Sbase−bandMPSK (f ) = 2Ebk
(sin πfkTb
πfkTb
)2. (15)
From the above equation it is clear that null-to-null bandwidth correspondingto M ary PSK is given by
Bnull−to−nullT =
2kTb
=2Rb
k. (16)
However, if we take 3 dB bandwidth as the criteria, then the correspondingbandwidth is given by
B3 dBT =
1kTb
=Rbk
. (17)
So, bandwidth efficiency is defined as
Bandwidth efficiency =Rb
B3 dBT
= k. (18)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bandwidth & Bandwidth Efficiency of MPSK
For MPSK, the baseband PSD is given by
Sbase−bandMPSK (f ) = 2Ebk
(sin πfkTb
πfkTb
)2. (15)
From the above equation it is clear that null-to-null bandwidth correspondingto M ary PSK is given by
Bnull−to−nullT =
2kTb
=2Rb
k. (16)
However, if we take 3 dB bandwidth as the criteria, then the correspondingbandwidth is given by
B3 dBT =
1kTb
=Rbk
. (17)
So, bandwidth efficiency is defined as
Bandwidth efficiency =Rb
B3 dBT
= k. (18)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bandwidth & Bandwidth Efficiency of MPSK
For MPSK, the baseband PSD is given by
Sbase−bandMPSK (f ) = 2Ebk
(sin πfkTb
πfkTb
)2. (15)
From the above equation it is clear that null-to-null bandwidth correspondingto M ary PSK is given by
Bnull−to−nullT =
2kTb
=2Rb
k. (16)
However, if we take 3 dB bandwidth as the criteria, then the correspondingbandwidth is given by
B3 dBT =
1kTb
=Rbk
. (17)
So, bandwidth efficiency is defined as
Bandwidth efficiency =Rb
B3 dBT
= k. (18)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bandwidth & Bandwidth Efficiency of MPSK
For MPSK, the baseband PSD is given by
Sbase−bandMPSK (f ) = 2Ebk
(sin πfkTb
πfkTb
)2. (15)
From the above equation it is clear that null-to-null bandwidth correspondingto M ary PSK is given by
Bnull−to−nullT =
2kTb
=2Rb
k. (16)
However, if we take 3 dB bandwidth as the criteria, then the correspondingbandwidth is given by
B3 dBT =
1kTb
=Rbk
. (17)
So, bandwidth efficiency is defined as
Bandwidth efficiency =Rb
B3 dBT
= k. (18)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bandwidth & Bandwidth Efficiency of MPSK
For MPSK, the baseband PSD is given by
Sbase−bandMPSK (f ) = 2Ebk
(sin πfkTb
πfkTb
)2. (15)
From the above equation it is clear that null-to-null bandwidth correspondingto M ary PSK is given by
Bnull−to−nullT =
2kTb
=2Rb
k. (16)
However, if we take 3 dB bandwidth as the criteria, then the correspondingbandwidth is given by
B3 dBT =
1kTb
=Rbk
. (17)
So, bandwidth efficiency is defined as
Bandwidth efficiency =Rb
B3 dBT
= k. (18)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Outline
1 Introduction
2 Phase Shift Keying (PSK)
3 Differential PSK (DPSK)
4 Frequency Shift Keying (FSK)
5 ASK & APK
6 Summary
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Coherence Requirement for MPSK
In MPSK, since the information is in the phase of the transmitted waveform,coherence between Tx& Rx is a must.
For BPSK, if RF phase changes by angle θ, it can be shown that the probabilityof bit error changes to
P′B = Q
[cos θ
√2EbN0
]. (19)
In order to make PSK amenable to non coherent detection, Differential PSK(DPSK) is used.
In DPSK, phase of the current symbol is not transmitted, but the phase differ-ence between current and previous symbols is transmitted. This avoids thenecessity of a coherent carrier at the receiver.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Coherence Requirement for MPSK
In MPSK, since the information is in the phase of the transmitted waveform,coherence between Tx& Rx is a must.
For BPSK, if RF phase changes by angle θ, it can be shown that the probabilityof bit error changes to
P′B = Q
[cos θ
√2EbN0
]. (19)
In order to make PSK amenable to non coherent detection, Differential PSK(DPSK) is used.
In DPSK, phase of the current symbol is not transmitted, but the phase differ-ence between current and previous symbols is transmitted. This avoids thenecessity of a coherent carrier at the receiver.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Coherence Requirement for MPSK
In MPSK, since the information is in the phase of the transmitted waveform,coherence between Tx& Rx is a must.
For BPSK, if RF phase changes by angle θ, it can be shown that the probabilityof bit error changes to
P′B = Q
[cos θ
√2EbN0
]. (19)
In order to make PSK amenable to non coherent detection, Differential PSK(DPSK) is used.
In DPSK, phase of the current symbol is not transmitted, but the phase differ-ence between current and previous symbols is transmitted. This avoids thenecessity of a coherent carrier at the receiver.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Coherence Requirement for MPSK
In MPSK, since the information is in the phase of the transmitted waveform,coherence between Tx& Rx is a must.
For BPSK, if RF phase changes by angle θ, it can be shown that the probabilityof bit error changes to
P′B = Q
[cos θ
√2EbN0
]. (19)
In order to make PSK amenable to non coherent detection, Differential PSK(DPSK) is used.
In DPSK, phase of the current symbol is not transmitted, but the phase differ-ence between current and previous symbols is transmitted. This avoids thenecessity of a coherent carrier at the receiver.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Coherence Requirement for MPSK
In MPSK, since the information is in the phase of the transmitted waveform,coherence between Tx& Rx is a must.
For BPSK, if RF phase changes by angle θ, it can be shown that the probabilityof bit error changes to
P′B = Q
[cos θ
√2EbN0
]. (19)
In order to make PSK amenable to non coherent detection, Differential PSK(DPSK) is used.
In DPSK, phase of the current symbol is not transmitted, but the phase differ-ence between current and previous symbols is transmitted. This avoids thenecessity of a coherent carrier at the receiver.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Differential Phase Shift Keying (D8PSK)
Symbol ∆φ
000 0001 π/4011 2π/4010 3π/4110 4π/4111 5π/4101 6π/4100 7π/4
Modulation ref
Symbol 110 001 110 010∆φk π π/4 π 3π/4
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
Demodulation ref
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
∆φk = φk − φk−1 π π/4 π 3π/4Recovered symbol 110 001 110 010
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Differential Phase Shift Keying (D8PSK)
Symbol ∆φ
000 0001 π/4011 2π/4010 3π/4110 4π/4111 5π/4101 6π/4100 7π/4
Modulation ref
Symbol 110 001 110 010∆φk π π/4 π 3π/4
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
Demodulation ref
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
∆φk = φk − φk−1 π π/4 π 3π/4Recovered symbol 110 001 110 010
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Differential Phase Shift Keying (D8PSK)
Symbol ∆φ
000 0001 π/4011 2π/4010 3π/4110 4π/4111 5π/4101 6π/4100 7π/4
Modulation ref
Symbol 110 001 110 010∆φk π π/4 π 3π/4
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
Demodulation ref
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
∆φk = φk − φk−1 π π/4 π 3π/4Recovered symbol 110 001 110 010
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Differential Phase Shift Keying (D8PSK)
Symbol ∆φ
000 0001 π/4011 2π/4010 3π/4110 4π/4111 5π/4101 6π/4100 7π/4
Modulation ref
Symbol 110 001 110 010
∆φk π π/4 π 3π/4φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
Demodulation ref
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
∆φk = φk − φk−1 π π/4 π 3π/4Recovered symbol 110 001 110 010
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Differential Phase Shift Keying (D8PSK)
Symbol ∆φ
000 0001 π/4011 2π/4010 3π/4110 4π/4111 5π/4101 6π/4100 7π/4
Modulation ref
Symbol 110 001 110 010∆φk π π/4 π 3π/4
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
Demodulation ref
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
∆φk = φk − φk−1 π π/4 π 3π/4Recovered symbol 110 001 110 010
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Differential Phase Shift Keying (D8PSK)
Symbol ∆φ
000 0001 π/4011 2π/4010 3π/4110 4π/4111 5π/4101 6π/4100 7π/4
Modulation ref
Symbol 110 001 110 010∆φk π π/4 π 3π/4
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
Demodulation ref
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
∆φk = φk − φk−1 π π/4 π 3π/4Recovered symbol 110 001 110 010
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Differential Phase Shift Keying (D8PSK)
Symbol ∆φ
000 0001 π/4011 2π/4010 3π/4110 4π/4111 5π/4101 6π/4100 7π/4
Modulation ref
Symbol 110 001 110 010∆φk π π/4 π 3π/4
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
Demodulation ref
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
∆φk = φk − φk−1 π π/4 π 3π/4Recovered symbol 110 001 110 010
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Differential Phase Shift Keying (D8PSK)
Symbol ∆φ
000 0001 π/4011 2π/4010 3π/4110 4π/4111 5π/4101 6π/4100 7π/4
Modulation ref
Symbol 110 001 110 010∆φk π π/4 π 3π/4
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
Demodulation ref
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
∆φk = φk − φk−1 π π/4 π 3π/4Recovered symbol 110 001 110 010
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Differential Phase Shift Keying (D8PSK)
Symbol ∆φ
000 0001 π/4011 2π/4010 3π/4110 4π/4111 5π/4101 6π/4100 7π/4
Modulation ref
Symbol 110 001 110 010∆φk π π/4 π 3π/4
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
Demodulation ref
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
∆φk = φk − φk−1 π π/4 π 3π/4
Recovered symbol 110 001 110 010
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Differential Phase Shift Keying (D8PSK)
Symbol ∆φ
000 0001 π/4011 2π/4010 3π/4110 4π/4111 5π/4101 6π/4100 7π/4
Modulation ref
Symbol 110 001 110 010∆φk π π/4 π 3π/4
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
Demodulation ref
φk = φk−1 + ∆φk 0 π 5π/4 π/4 π
∆φk = φk − φk−1 π π/4 π 3π/4Recovered symbol 110 001 110 010
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Binary Differential Phase Shift Keying (DBPSK)
Symbol ∆φ
1 00 π
Modulation ref
Symbol / Bit 1 0 1 1 0 0∆φk 0 π 0 0 π π
φk = φk−1 + ∆φk 0 0 π π π 0 π
Demodulation
φk = φk−1 + ∆φk 0 0 π π π 0 π
∆φk = φk − φk−1 0 π 0 0 π π
Recovered Symbol / Bit 1 0 1 1 0 0
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Binary Differential Phase Shift Keying (DBPSK)
Symbol ∆φ
1 00 π
Modulation ref
Symbol / Bit 1 0 1 1 0 0∆φk 0 π 0 0 π π
φk = φk−1 + ∆φk 0 0 π π π 0 π
Demodulation
φk = φk−1 + ∆φk 0 0 π π π 0 π
∆φk = φk − φk−1 0 π 0 0 π π
Recovered Symbol / Bit 1 0 1 1 0 0
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Binary Differential Phase Shift Keying (DBPSK)
Symbol ∆φ
1 00 π
Modulation ref
Symbol / Bit 1 0 1 1 0 0∆φk 0 π 0 0 π π
φk = φk−1 + ∆φk 0 0 π π π 0 π
Demodulation
φk = φk−1 + ∆φk 0 0 π π π 0 π
∆φk = φk − φk−1 0 π 0 0 π π
Recovered Symbol / Bit 1 0 1 1 0 0
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Binary Differential Phase Shift Keying (DBPSK)
Symbol ∆φ
1 00 π
Modulation ref
Symbol / Bit 1 0 1 1 0 0∆φk 0 π 0 0 π π
φk = φk−1 + ∆φk 0 0 π π π 0 π
Demodulation
φk = φk−1 + ∆φk 0 0 π π π 0 π
∆φk = φk − φk−1 0 π 0 0 π π
Recovered Symbol / Bit 1 0 1 1 0 0
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Binary Differential Phase Shift Keying (DBPSK)
Modulation ref
Message ak 1 0 1 1 0 0 0 1 1Encoding dk = ak ⊕ dk−1 1 1 0 0 0 1 0 1 1 1
Signal phase φ 0 0 π π π 0 π 0 0 0Transmitted NRZ-L signal 1 1 -1 -1 -1 1 -1 1 1 1
Demodulation
Sk (t) 1 1 -1 -1 -1 1 -1 1 1 11
Eb
´ (k+1)TSkTS
Sk (t) Sk−1 (t) dt 1 -1 1 1 -1 -1 -1 1 1
Demodulator output ak 1 0 1 1 0 0 0 1 1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Binary Differential Phase Shift Keying (DBPSK)
Modulation ref
Message ak 1 0 1 1 0 0 0 1 1Encoding dk = ak ⊕ dk−1 1 1 0 0 0 1 0 1 1 1
Signal phase φ 0 0 π π π 0 π 0 0 0Transmitted NRZ-L signal 1 1 -1 -1 -1 1 -1 1 1 1
Demodulation
Sk (t) 1 1 -1 -1 -1 1 -1 1 1 11
Eb
´ (k+1)TSkTS
Sk (t) Sk−1 (t) dt 1 -1 1 1 -1 -1 -1 1 1
Demodulator output ak 1 0 1 1 0 0 0 1 1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Binary Differential Phase Shift Keying (DBPSK)
Modulation ref
Message ak 1 0 1 1 0 0 0 1 1Encoding dk = ak ⊕ dk−1 1 1 0 0 0 1 0 1 1 1
Signal phase φ 0 0 π π π 0 π 0 0 0Transmitted NRZ-L signal 1 1 -1 -1 -1 1 -1 1 1 1
Demodulation
Sk (t) 1 1 -1 -1 -1 1 -1 1 1 11
Eb
´ (k+1)TSkTS
Sk (t) Sk−1 (t) dt 1 -1 1 1 -1 -1 -1 1 1
Demodulator output ak 1 0 1 1 0 0 0 1 1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
DBPSK Modulation & Demodulation
DelayT
LogicdeviceBinary data
{ak}
(0, 1)
dk-1
Binary DPSK Modulator
dk = ak ⊕ dk−1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
DBPSK Modulation & Demodulation
DelayT
LogicdeviceBinary data
{ak}
(0, 1)
dk-1
Binary DPSK Modulator
dk = ak ⊕ dk−1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
DBPSK Modulation & Demodulation
DelayT
LogicdeviceBinary data
{ak}
(0, 1)
dk-1
Binary DPSK Modulator
dk = ak ⊕ dk−1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
DBPSKModulation & Demodulation
DelayT
LogicdeviceBinary data
{ak}
(0, 1)
dkdk-1
{dk}(0, 1)
Binary DPSK Modulator
dk = ak ⊕ dk−1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
DBPSK Modulation & Demodulation
DelayT
Levelgenerator
Logicdevice Polar NRZ
d(t)Binary data
{ak}
(0, 1)
dkdk-1
{dk}(0, 1) (-1, 1)
Binary DPSK Modulator
dk = ak ⊕ dk−1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
DBPSK Modulation & Demodulation
DelayT
Levelgenerator
Logicdevice Polar NRZ
d(t)Binary data
{ak}
(0, 1)
dkdk-1
{dk}(0, 1) (-1, 1)
Binary DPSK Modulator
dk = ak ⊕ dk−1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
DBPSK Modulation & Demodulation
r(t)
DelayT
Binary DPSK Demodulator
DelayT
Levelgenerator
Logicdevice Polar NRZ
d(t)Binary data
{ak}
(0, 1)
dkdk-1
{dk}(0, 1) (-1, 1)
Binary DPSK Modulator
dk = ak ⊕ dk−1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
DBPSK Modulation & Demodulation
∫0
Tr(t)
DelayT
Binary DPSK Demodulator
DelayT
Levelgenerator
Logicdevice Polar NRZ
d(t)Binary data
{ak}
(0, 1)
dkdk-1
{dk}(0, 1) (-1, 1)
Binary DPSK Modulator
dk = ak ⊕ dk−1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
DBPSK Modulation & Demodulation
si
>∫0
Tr(t)
Decisionstage
DelayT
Binary DPSK Demodulator
DelayT
Levelgenerator
Logicdevice Polar NRZ
d(t)Binary data
{ak}
(0, 1)
dkdk-1
{dk}(0, 1) (-1, 1)
Binary DPSK Modulator
dk = ak ⊕ dk−1
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Two Different Types of DBPSK Demodulators
si
>∫0
Tr(t)
Decisionstage
DelayT
Sub-Optimal Demodulator
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Two Different Types of DBPSK Demodulators
si
>∫0
Tr(t)
Decisionstage
DelayT
Sub-Optimal Demodulator
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Two Different Types of DBPSK Demodulators
si
>∫0
Tr(t)
Decisionstage
DelayT
si
>∫0
Tr(t)
Decisionstage
DelayT
Sub-Optimal Demodulator
Optimal DemodulatorFrom local
osicllator
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
DBPSK – Probability of Errors
0 5 10 1510 8
10 7
10 6
10 5
10 4
10 3
0.01
0.1
1
SuboptimumDBPSK
Optimum DBPSK
CoherentDEBPSK
Coherent BPSK
Pb
E b/ No (dB)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
DBPSK – Probability of Errors
0 5 10 1510 8
10 7
10 6
10 5
10 4
10 3
0.01
0.1
1
SuboptimumDBPSK
Optimum DBPSK
CoherentDEBPSK
Coherent BPSK
Pb
E b/ No (dB)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Outline
1 Introduction
2 Phase Shift Keying (PSK)
3 Differential PSK (DPSK)
4 Frequency Shift Keying (FSK)
5 ASK & APK
6 Summary
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
A Simple Introduction to FSK (BFSK)
2π
Tb
4π
Tb
6π
Tb
8π
Tb
2π
Tb
4π
Tb
6π
Tb
8π
Tb
0ω
On-offLine-codespectrum
ω
FSKspectrum
-ω2 +ω1
Frequency shift keying
0 1 0 1 1 0 1 0 1 1
ASK 1
ASK 2
+
1 V
-1 V
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Generating BFSK on Emona Kit
IN 2
CON 1
Dual AnalogSwitch
CON 2
IN 1
NoiseGenerator
DC 5VFixed
Exor Module
X
VCO
Multipliermodule
BasebandLPF
TuneableLPF
Multipliermodule
To Ch. 1
To Ch. 2
100 kHzcos
~ 85 kHz
Ref
Baseband Data FSK Modulation Adding Noise FSK Demodulation / Detection
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Coherent vs Non-Coherent FSK
In its most general form, the binary FSK scheme uses two signals with differ-ent frequencies to represent binary 1 and 0.
S1 (t) =
√2ESTS
cos (2πf1t + Φ1) , kTb ≤ t ≤ (k + 1)TS, for 1
S2 (t) =
√2ESTS
cos (2πf2t + Φ2) , kTb ≤ t ≤ (k + 1)TS, for 0
where Φ1 and Φ2 are initial phases at t = 0, and TS is the symbol period of thedigital data.
When Φ1 = Φ2, this form of FSK is called coherent FSK.
When Φ1 6= Φ2, this form of FSK is called noncoherent or discontinuous FSK.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Condition for Orthogonality – Noncoherent FSK
If signals S1 (t) and S2 (t) are orthogonalˆ TS
0S1 (t) S2 (t) dt = 0
⇒ˆ TS
0cos (2πf1t + Φ1) cos (2πf2t + Φ2) dt = 0
⇓
sin [2π (f1 + f2)TS]
2π (f1 + f2)cos (Φ1 + Φ2) +
sin [2π (f1 − f2)TS]
2π (f1 − f2)cos (Φ1 −Φ2)
+cos [2π (f1 + f2)TS]− 1
2π (f1 + f2)sin (Φ1 + Φ2)+
cos [2π (f1 − f2)TS]− 12π (f1 − f2)
sin (Φ1 −Φ2) = 0
Both sin x = 0 and cos x = 1 occur simultaneously when x = 2mπ. So,f1 + f2 = m/TS. Similarly it can be proved that f1 − f2 = n/TS.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Condition for Orthogonality – Coherent FSK
For coherent FSK, Φ1 = Φ2 = Φ. So, the equation given in the previous slidebecomes
⇓
sin [2π (f1 + f2)TS]
2π (f1 + f2)cos 2Φ +
sin [2π (f1 − f2)TS]
2π (f1 − f2)
+cos [2π (f1 + f2)TS]− 1
2π (f1 + f2)sin 2Φ = 0
Both sin x = 0 and cos x = 1 occur simultaneously when x = 2mπ. So,f1 + f2 = m/TS. Similarly it can be proved that f1 − f2 = n/2TS.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
So, Conditions for Orthogonality are
Non-Coherent FSK:
f1 + f2 = m/TS
f1 − f2= n/TS
Coherent FSK:
f1 + f2 = m/TS
f1 − f2= n/2TS
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BFSK vs 4FSK
BFSK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BFSK vs 4FSK
BFSK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
BFSK vs 4FSK
BFSK
4FSK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MFSK Generation
Multiplexer
Oscillator 1
Oscillator 2
Oscillator M
Control lines
Binary input data S / PConverter
bnb1 b2
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MFSK Generation
Multiplexer
Oscillator 1
Oscillator 2
Oscillator M
Control lines
Binary input data S / PConverter
bnb1 b2
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Coherent MFSK Detection
∫0
Ts
r(t)
∫0
Ts
Logic circuitselects Si(t)
whosecomponentsaij best match
{zj(T)}
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Coherent MFSK Detection – PS & PB
The symbol error probability for a coherently detected MFSK system has anupper bound, given as
PS ≤ (M− 1)Q
(√ESN0
). (20)
Can you visualize the above equation geometrically?
In MFSK, the ratio of the bit error probability to the symbol error probabilityis
PBPS
=M/2
M− 1. (21)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Coherent MFSK Detection – PS & PB
The symbol error probability for a coherently detected MFSK system has anupper bound, given as
PS ≤ (M− 1)Q
(√ESN0
). (20)
Can you visualize the above equation geometrically?
In MFSK, the ratio of the bit error probability to the symbol error probabilityis
PBPS
=M/2
M− 1. (21)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Coherent MFSK Detection – PS & PB
The symbol error probability for a coherently detected MFSK system has anupper bound, given as
PS ≤ (M− 1)Q
(√ESN0
). (20)
Can you visualize the above equation geometrically?
In MFSK, the ratio of the bit error probability to the symbol error probabilityis
PBPS
=M/2
M− 1. (21)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Coherent MFSK Detection – PS & PB
The symbol error probability for a coherently detected MFSK system has anupper bound, given as
PS ≤ (M− 1)Q
(√ESN0
). (20)
Can you visualize the above equation geometrically?
In MFSK, the ratio of the bit error probability to the symbol error probabilityis
PBPS
=M/2
M− 1. (21)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Non-Coherent MFSK Detection
z γ0>< si
>Σ z(T)
z1(T)∫0
T
r(t)
z2(T)∫0
T
z21
( )2.
( )2.z2
2
I channel
Q channelΣ
z3(T)∫0
T
z4(T)∫0
T
z23
( )2.
( )2.z2
4
I channel
Q channelΣ
+
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Non-Coherent MFSK Detection
z γ0>< si
>Σ z(T)
z1(T)∫0
T
r(t)
z2(T)∫0
T
z21
( )2.
( )2.z2
2
I channel
Q channelΣ
z3(T)∫0
T
z4(T)∫0
T
z23
( )2.
( )2.z2
4
I channel
Q channelΣ
+
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Non-Coherent MFSK Detection
r(t)
z1(T)
Filterf1
Envelopdetector
z3(T)
Envelopdetector
FilterfM
si
>
Decisionstage
z2(T)
Envelopdetector
Filterf2
Bandpass filters centeredat fi with bandwidth Wf = 1/T
In no noise case, assuming that the filters preserve the shape of the envelopeof the input signal waveforms, the output is of the type
z (T) =√
2ES/TS. (22)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Non-Coherent MFSK Detection
r(t)
z1(T)
Filterf1
Envelopdetector
z3(T)
Envelopdetector
FilterfM
si
>
Decisionstage
z2(T)
Envelopdetector
Filterf2
Bandpass filters centeredat fi with bandwidth Wf = 1/T
In no noise case, assuming that the filters preserve the shape of the envelopeof the input signal waveforms, the output is of the type
z (T) =√
2ES/TS. (22)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Non-Coherent MFSK Detection
r(t)
z1(T)
Filterf1
Envelopdetector
z3(T)
Envelopdetector
FilterfM
si
>
Decisionstage
z2(T)
Envelopdetector
Filterf2
Bandpass filters centeredat fi with bandwidth Wf = 1/T
In no noise case, assuming that the filters preserve the shape of the envelopeof the input signal waveforms, the output is of the type
z (T) =√
2ES/TS. (22)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Non-Coherent MFSK Detection – PS & PB
In the case of coherent detection, the pdf of the (signal + noise), at the inputof the decision stage, remained Gaussian.
In the case of non coherent detection, the pdf of the envelops of (signal +noise), at the input of the decision stage, do not remain Gaussian.
So, first, we need the knowledge of pdf of (signal + noise) at the decisionstage to evaluate the symbol / bit error probabilities.
The symbol error probability for a non coherently detected MFSK system isgiven as
PS =1M
exp(− ES
N0
) M
∑j=2
(−1)j(
Mj
)exp
(ES
jN0
), where
(Mj
)=
M!j! (M− j)!
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Non-Coherent MFSK Detection – PS & PB
In the case of coherent detection, the pdf of the (signal + noise), at the inputof the decision stage, remained Gaussian.
In the case of non coherent detection, the pdf of the envelops of (signal +noise), at the input of the decision stage, do not remain Gaussian.
So, first, we need the knowledge of pdf of (signal + noise) at the decisionstage to evaluate the symbol / bit error probabilities.
The symbol error probability for a non coherently detected MFSK system isgiven as
PS =1M
exp(− ES
N0
) M
∑j=2
(−1)j(
Mj
)exp
(ES
jN0
), where
(Mj
)=
M!j! (M− j)!
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Non-Coherent MFSK Detection – PS & PB
In the case of coherent detection, the pdf of the (signal + noise), at the inputof the decision stage, remained Gaussian.
In the case of non coherent detection, the pdf of the envelops of (signal +noise), at the input of the decision stage, do not remain Gaussian.
So, first, we need the knowledge of pdf of (signal + noise) at the decisionstage to evaluate the symbol / bit error probabilities.
The symbol error probability for a non coherently detected MFSK system isgiven as
PS =1M
exp(− ES
N0
) M
∑j=2
(−1)j(
Mj
)exp
(ES
jN0
), where
(Mj
)=
M!j! (M− j)!
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Non-Coherent MFSK Detection – PS & PB
In the case of coherent detection, the pdf of the (signal + noise), at the inputof the decision stage, remained Gaussian.
In the case of non coherent detection, the pdf of the envelops of (signal +noise), at the input of the decision stage, do not remain Gaussian.
So, first, we need the knowledge of pdf of (signal + noise) at the decisionstage to evaluate the symbol / bit error probabilities.
The symbol error probability for a non coherently detected MFSK system isgiven as
PS =1M
exp(− ES
N0
) M
∑j=2
(−1)j(
Mj
)exp
(ES
jN0
), where
(Mj
)=
M!j! (M− j)!
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Non-Coherent MFSK Detection – PS & PB
In the case of coherent detection, the pdf of the (signal + noise), at the inputof the decision stage, remained Gaussian.
In the case of non coherent detection, the pdf of the envelops of (signal +noise), at the input of the decision stage, do not remain Gaussian.
So, first, we need the knowledge of pdf of (signal + noise) at the decisionstage to evaluate the symbol / bit error probabilities.
The symbol error probability for a non coherently detected MFSK system isgiven as
PS =1M
exp(− ES
N0
) M
∑j=2
(−1)j(
Mj
)exp
(ES
jN0
), where
(Mj
)=
M!j! (M− j)!
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectrum of MFSK
Frequency
Spec
trum
of M
FSK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Spectrum of MFSK
Frequency
Spec
trum
of M
FSK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bandwidth & Bandwidth Efficiency of MFSK
Bandwidth
Non-Coherent MFSK: BT = M/TS
Coherent MFSK: BT = M/2TS
Bit rate Rb = 1/Tb = log2 M/TS = k/TS
Bandwidth Efficiency
(R/W)NCMFSK = Rb/BT = (1/M) log2 M
(R/W)CMFSK = Rb/BT = (2/M) log2 M
So, (R/W)NCMFSK is better than (R/W)NCMFSK.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bandwidth & Bandwidth Efficiency of MFSK
Bandwidth
Non-Coherent MFSK: BT = M/TS
Coherent MFSK: BT = M/2TS
Bit rate Rb = 1/Tb = log2 M/TS = k/TS
Bandwidth Efficiency
(R/W)NCMFSK = Rb/BT = (1/M) log2 M
(R/W)CMFSK = Rb/BT = (2/M) log2 M
So, (R/W)NCMFSK is better than (R/W)NCMFSK.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Bandwidth & Bandwidth Efficiency of MFSK
Bandwidth
Non-Coherent MFSK: BT = M/TS
Coherent MFSK: BT = M/2TS
Bit rate Rb = 1/Tb = log2 M/TS = k/TS
Bandwidth Efficiency
(R/W)NCMFSK = Rb/BT = (1/M) log2 M
(R/W)CMFSK = Rb/BT = (2/M) log2 M
So, (R/W)NCMFSK is better than (R/W)NCMFSK.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Probability of Bit Errors for Various BinaryModulations
0 2 4 6 8 10 12 1410
-7
10-6
10-5
10-4
10-3
10-2
10-1
100
Eb/No in [dB]
Pro
ba
bili
ty o
f B
it E
rro
r
BPSK(QPSK)
ASK/FSK
NC FSK
DPSK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Probability of Bit Errors for Various BinaryModulations
0 2 4 6 8 10 12 1410
-7
10-6
10-5
10-4
10-3
10-2
10-1
100
Eb/No in [dB]
Pro
ba
bili
ty o
f B
it E
rro
r
BPSK(QPSK)
ASK/FSK
NC FSK
DPSK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Outline
1 Introduction
2 Phase Shift Keying (PSK)
3 Differential PSK (DPSK)
4 Frequency Shift Keying (FSK)
5 ASK & APK
6 Summary
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Amplitude Shift Keying (MASK)
(Bipolar MASK)
(Unipolar MASK)
M-ary ASK waveform is given as
SMASKi (t) = Ai
√2Es
TSsin (ω0t + φ) , i = 1, 2, · · · , M (23)
where√
ES is the energy of the nominal carrier in a symbol duration TS.
For unipolar binary ASK , it is called on-off keying (OOK). Binary 1 and 0 arerepresented by
√ES and 0, respectively, in the signal space.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Amplitude Shift Keying (MASK)
(Bipolar MASK)
(Unipolar MASK)
M-ary ASK waveform is given as
SMASKi (t) = Ai
√2Es
TSsin (ω0t + φ) , i = 1, 2, · · · , M (23)
where√
ES is the energy of the nominal carrier in a symbol duration TS.
For unipolar binary ASK , it is called on-off keying (OOK). Binary 1 and 0 arerepresented by
√ES and 0, respectively, in the signal space.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Amplitude Shift Keying (MASK)
(Bipolar MASK)
(Unipolar MASK)
M-ary ASK waveform is given as
SMASKi (t) = Ai
√2Es
TSsin (ω0t + φ) , i = 1, 2, · · · , M (23)
where√
ES is the energy of the nominal carrier in a symbol duration TS.
For unipolar binary ASK , it is called on-off keying (OOK). Binary 1 and 0 arerepresented by
√ES and 0, respectively, in the signal space.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Amplitude Shift Keying (MASK)
(Bipolar MASK)
(Unipolar MASK)
M-ary ASK waveform is given as
SMASKi (t) = Ai
√2Es
TSsin (ω0t + φ) , i = 1, 2, · · · , M (23)
where√
ES is the energy of the nominal carrier in a symbol duration TS.
For unipolar binary ASK , it is called on-off keying (OOK). Binary 1 and 0 arerepresented by
√ES and 0, respectively, in the signal space.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MASK – PS & PB
It can be shown that the symbol error probability for bipolar MASK is
PS =2 (M− 1)
MQ
(√6Eavg
(M2 − 1)N0
). (24)
Similarly, the symbol error probability for unipolar MASK is
PS =2 (M− 1)
MQ
(√3Eavg
(2M2 − 3M + 1)N0
). (25)
Eavg (average symbol energy) can be written in terms of average bit energy,Eb, as
Eavg = (log2 M)Eb = kEb. (26)
At high signal-to-noise ratios, the most likely errors are the adjacent symbols(when we use Gray code). So in this case
Pb ≈PS
log2 M=
PSk
. (27)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MASK – PS & PB
It can be shown that the symbol error probability for bipolar MASK is
PS =2 (M− 1)
MQ
(√6Eavg
(M2 − 1)N0
). (24)
Similarly, the symbol error probability for unipolar MASK is
PS =2 (M− 1)
MQ
(√3Eavg
(2M2 − 3M + 1)N0
). (25)
Eavg (average symbol energy) can be written in terms of average bit energy,Eb, as
Eavg = (log2 M)Eb = kEb. (26)
At high signal-to-noise ratios, the most likely errors are the adjacent symbols(when we use Gray code). So in this case
Pb ≈PS
log2 M=
PSk
. (27)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MASK – PS & PB
It can be shown that the symbol error probability for bipolar MASK is
PS =2 (M− 1)
MQ
(√6Eavg
(M2 − 1)N0
). (24)
Similarly, the symbol error probability for unipolar MASK is
PS =2 (M− 1)
MQ
(√3Eavg
(2M2 − 3M + 1)N0
). (25)
Eavg (average symbol energy) can be written in terms of average bit energy,Eb, as
Eavg = (log2 M)Eb = kEb. (26)
At high signal-to-noise ratios, the most likely errors are the adjacent symbols(when we use Gray code). So in this case
Pb ≈PS
log2 M=
PSk
. (27)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MASK – PS & PB
It can be shown that the symbol error probability for bipolar MASK is
PS =2 (M− 1)
MQ
(√6Eavg
(M2 − 1)N0
). (24)
Similarly, the symbol error probability for unipolar MASK is
PS =2 (M− 1)
MQ
(√3Eavg
(2M2 − 3M + 1)N0
). (25)
Eavg (average symbol energy) can be written in terms of average bit energy,Eb, as
Eavg = (log2 M)Eb = kEb. (26)
At high signal-to-noise ratios, the most likely errors are the adjacent symbols(when we use Gray code). So in this case
Pb ≈PS
log2 M=
PSk
. (27)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MASK – PS & PB
It can be shown that the symbol error probability for bipolar MASK is
PS =2 (M− 1)
MQ
(√6Eavg
(M2 − 1)N0
). (24)
Similarly, the symbol error probability for unipolar MASK is
PS =2 (M− 1)
MQ
(√3Eavg
(2M2 − 3M + 1)N0
). (25)
Eavg (average symbol energy) can be written in terms of average bit energy,Eb, as
Eavg = (log2 M)Eb = kEb. (26)
At high signal-to-noise ratios, the most likely errors are the adjacent symbols(when we use Gray code). So in this case
Pb ≈PS
log2 M=
PSk
. (27)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MASK – Bandwidth & Bandwidth Efficiency
Power spectral density of MASK will have the same shape as that of MPSK.So, transmission bandwidth is given as
BT =1
kTb=
Rbk
. (28)
So, bandwidth efficiency is for MASK is
Bandwidth efficiency =RbBT
= k = log2 M. (29)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MASK – Bandwidth & Bandwidth Efficiency
Power spectral density of MASK will have the same shape as that of MPSK.So, transmission bandwidth is given as
BT =1
kTb=
Rbk
. (28)
So, bandwidth efficiency is for MASK is
Bandwidth efficiency =RbBT
= k = log2 M. (29)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MASK – Bandwidth & Bandwidth Efficiency
Power spectral density of MASK will have the same shape as that of MPSK.So, transmission bandwidth is given as
BT =1
kTb=
Rbk
. (28)
So, bandwidth efficiency is for MASK is
Bandwidth efficiency =RbBT
= k = log2 M. (29)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Why ASK is Bad?
0 2 4 6 8 10 12 1410
-7
10-6
10-5
10-4
10-3
10-2
10-1
100
Eb/No in [dB]
Pro
ba
bili
ty o
f B
it E
rro
r
BPSK(QPSK)
ASK/FSK
NC FSK
DPSK
From the above figure, it clear that MASK is usually not preferred due to itspoor power efficiency.
We also know that MPSK constellation diagram gets crowded as M increases.
So, we need to come up with a modulation technique which shares features ofboth MPSK and MASK.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Why ASK is Bad?
0 2 4 6 8 10 12 1410
-7
10-6
10-5
10-4
10-3
10-2
10-1
100
Eb/No in [dB]
Pro
ba
bili
ty o
f B
it E
rro
rBPSK(QPSK)
ASK/FSK
NC FSK
DPSK
From the above figure, it clear that MASK is usually not preferred due to itspoor power efficiency.
We also know that MPSK constellation diagram gets crowded as M increases.
So, we need to come up with a modulation technique which shares features ofboth MPSK and MASK.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Why ASK is Bad?
0 2 4 6 8 10 12 1410
-7
10-6
10-5
10-4
10-3
10-2
10-1
100
Eb/No in [dB]
Pro
ba
bili
ty o
f B
it E
rro
rBPSK(QPSK)
ASK/FSK
NC FSK
DPSK
From the above figure, it clear that MASK is usually not preferred due to itspoor power efficiency.
We also know that MPSK constellation diagram gets crowded as M increases.
So, we need to come up with a modulation technique which shares features ofboth MPSK and MASK.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Why ASK is Bad?
0 2 4 6 8 10 12 1410
-7
10-6
10-5
10-4
10-3
10-2
10-1
100
Eb/No in [dB]
Pro
ba
bili
ty o
f B
it E
rro
rBPSK(QPSK)
ASK/FSK
NC FSK
DPSK
From the above figure, it clear that MASK is usually not preferred due to itspoor power efficiency.
We also know that MPSK constellation diagram gets crowded as M increases.
So, we need to come up with a modulation technique which shares features ofboth MPSK and MASK.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Why ASK is Bad?
0 2 4 6 8 10 12 1410
-7
10-6
10-5
10-4
10-3
10-2
10-1
100
Eb/No in [dB]
Pro
ba
bili
ty o
f B
it E
rro
rBPSK(QPSK)
ASK/FSK
NC FSK
DPSK
From the above figure, it clear that MASK is usually not preferred due to itspoor power efficiency.
We also know that MPSK constellation diagram gets crowded as M increases.
So, we need to come up with a modulation technique which shares features ofboth MPSK and MASK.
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
ASK + PSK = APK
ASK
PSK
ASK/PSK (APK)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
ASK + PSK = APK
ASK
PSK
ASK/PSK (APK)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MAPK (Quadrature Amplitude Modulation)
For MAPK,
SMAPKi (t) = Ai
√2Es
TSsin (ω0t + φi) , i = 1, 2, · · · , M. (30)
To get x and y coordinates corresponding to the signal in the constellationdiagram, the above equation can be re-written as
SMAPKi (t) = Ai
√Es cos φi︸ ︷︷ ︸
xi
ψ1 (t) + Ai√
Es sin φi︸ ︷︷ ︸yi
ψ2 (t) . (31)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MAPK (Quadrature Amplitude Modulation)
For MAPK,
SMAPKi (t) = Ai
√2Es
TSsin (ω0t + φi) , i = 1, 2, · · · , M. (30)
To get x and y coordinates corresponding to the signal in the constellationdiagram, the above equation can be re-written as
SMAPKi (t) = Ai
√Es cos φi︸ ︷︷ ︸
xi
ψ1 (t) + Ai√
Es sin φi︸ ︷︷ ︸yi
ψ2 (t) . (31)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MAPK (Quadrature Amplitude Modulation)
For MAPK,
SMAPKi (t) = Ai
√2Es
TSsin (ω0t + φi) , i = 1, 2, · · · , M. (30)
To get x and y coordinates corresponding to the signal in the constellationdiagram, the above equation can be re-written as
SMAPKi (t) = Ai
√Es cos φi︸ ︷︷ ︸
xi
ψ1 (t) + Ai√
Es sin φi︸ ︷︷ ︸yi
ψ2 (t) . (31)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
16 QAM
Q
I
0000 0100 1100 1000
0001 0101 1101 1001
0011 0111 1111 1011
0010 0110 1110 1010
Q
I
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
16 QAM
Q
I
0000 0100 1100 1000
0001 0101 1101 1001
0011 0111 1111 1011
0010 0110 1110 1010
Q
I
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
8 QAM
I
Q
I
Q
I
Q
(1+√3,0)
(1,1)
I
Q
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
8 QAM
I
Q
I
Q
I
Q
(1+√3,0)
(1,1)
I
Q
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
QAM – Modulation & Demodulation
X
Y
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
QAM – Modulation & Demodulation
X
Y
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
QAM – Modulation & Demodulation
X
Y
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MQAM – PS & PB
It can be shown that the symbol error probability for bipolar MQAM is giveninterms of symbol average energy Eavg as
PS ≤ 4Q
(√3kEb
(M− 1)N0
), (32)
where Eavg = (log2 M)Eb = kEb.
At high signal-to-noise ratios, the most likely errors are the adjacent symbols(when we use Gray code). So in this case
Pb ≈PS
log2 M=
PSk
. (33)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MQAM – PS & PB
It can be shown that the symbol error probability for bipolar MQAM is giveninterms of symbol average energy Eavg as
PS ≤ 4Q
(√3kEb
(M− 1)N0
), (32)
where Eavg = (log2 M)Eb = kEb.
At high signal-to-noise ratios, the most likely errors are the adjacent symbols(when we use Gray code). So in this case
Pb ≈PS
log2 M=
PSk
. (33)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MQAM – PS & PB
It can be shown that the symbol error probability for bipolar MQAM is giveninterms of symbol average energy Eavg as
PS ≤ 4Q
(√3kEb
(M− 1)N0
), (32)
where Eavg = (log2 M)Eb = kEb.
At high signal-to-noise ratios, the most likely errors are the adjacent symbols(when we use Gray code). So in this case
Pb ≈PS
log2 M=
PSk
. (33)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MQAM – Bandwidth & Bandwidth Efficiency
Power spectral density of MQAM will have the same shape as that of MPSK/ MASK. So, transmission bandwidth is given as
BT =1
kTb=
Rbk
. (34)
So, bandwidth efficiency is for MQAM is
Bandwidth efficiency =RbBT
= k = log2 M. (35)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MQAM – Bandwidth & Bandwidth Efficiency
Power spectral density of MQAM will have the same shape as that of MPSK/ MASK. So, transmission bandwidth is given as
BT =1
kTb=
Rbk
. (34)
So, bandwidth efficiency is for MQAM is
Bandwidth efficiency =RbBT
= k = log2 M. (35)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MQAM – Bandwidth & Bandwidth Efficiency
Power spectral density of MQAM will have the same shape as that of MPSK/ MASK. So, transmission bandwidth is given as
BT =1
kTb=
Rbk
. (34)
So, bandwidth efficiency is for MQAM is
Bandwidth efficiency =RbBT
= k = log2 M. (35)
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Comparison of MPSK, MQAM, and MFSK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Comparison of MPSK, MQAM, and MFSK
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
Outline
1 Introduction
2 Phase Shift Keying (PSK)
3 Differential PSK (DPSK)
4 Frequency Shift Keying (FSK)
5 ASK & APK
6 Summary
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad
Introduction Phase Shift Keying (PSK) Differential PSK (DPSK) Frequency Shift Keying (FSK) ASK & APK Summary
MPSK – Summary
SMPSKi (t) =
√2Es
TSsin(
ω0t +2πiM
), i = 1, 2, · · · , M
PMPSKS ≈ 2Q
(dmin√
2N0
)= 2Q
(√2Es
N0sin
π
M
), for large SNR
PMPSKB ≈ PS
log2 M(for PS � 1 and Gray coding)
Bandwidth efficiencyMPSK =RbBT
= log2 M
9. Bandpass Modulation and Demodulation Techniques Communication Systems, Dept. of EEE, BITS Hyderabad