SlideShare a Scribd company logo
1 of 28
Download to read offline
*
We use the term modulation to refer to
changes made in a carrier
-according to the information being sent
Modulation takes two inputs
-a carrier
-and a signal
* MSK FSK ASK
Modulation techniques
* Shift Keying
To distinguish between analog and digital
modulation
-We use the term shift keying rather
than modulation
Modulation techniques
*
 ASK is the abbreviation of Amplitude
Shift Keying
 Ask is called On-Off Keying.
 The simplest and most common form
of operate as a switch.
*
 It is Abbreviated as Frequency shift keying
 Values represented by different frequencies (near
carrier)
 Less susceptible to error than ASK
 Typically used up to 1200bps on voice grade lines
 High frequency radio
 Even higher frequency on LANs using co-ax
*
Amplitude and frequency modulations require at least one cycle
of a carrier wave to send a single bit
unless a special encoding scheme is used
The number of bits sent per unit time can be increased
if the encoding scheme permits multiple bits to be encoded in a
single cycle of the carrier
Data communications systems often use techniques that can
send more bits
PSK changes the phase of the carrier wave abruptly
each such change is called a phase shift
* Phase of carrier signal is shifted to represent data
Quadrature amplitude modulation is a
combination of ASK and PSK.
Note
*
To send more than one bit at a time
It is possible to send two bits on
one wave by defining four different
amplitudes.
The same approach can be used for
frequency and phase modulation.
Modulation techniques
In practice, the maximum number of bits that can
be sent with any one of these techniques is about
five bits. The solution is to combine modulation
techniques.
One popular technique is quadrature amplitude
modulation (QAM) involves splitting the signal
into eight different phases, and two different
amplitude for a total of 16 different possible
values, giving us lg(16) or 4 bits per value.
*
*
*Minimum Shift Keying
MSK is a variant of OQPSK
The rectangular symbol pulse is replaced by a half cycle
sinusoidal symbol pulse.
MSK provides a constant envelope signal which has it’s phase
continuous at all times including the interbit switching
times.
 In MSK, also the phase shifts can be detected with an I or Q
modulator.
 At even numbered symbols, the polarity of I channel conveys
the transmitted data and at odd numbered symbols the polarity
of Q channel conveys the data.
 A phase shift of + 90 degrees represents a data bit equal to 1 and a
phase shift of –90 degrees represents a data bit equal to zero
It possesses properties
such as:
constant envelope
spectral efficiency
good BER
performance
self-synchronizing
capability.
MSK PROPERTIES
*
*
• Gaussian Minimum Shift Keying
• Modulation scheme used in GSM
• Bandwidth-time product
• Describes the amount the symbols overlap
• BT = 0.3 for GSM networks
• Good spectral efficiency
• At the expense of some inter-symbol interference (ISI
• Data rate: 270.8 kbps
*
• GMSK is based on MSK
• Minimum Shift Keying
• Linear phase changes
• Spectrally efficient
• At baseband, bit transitions are represented by
½ cycle sinusoid
*
 Improved spectral efficiency
 Power Spectral Density
 Reduced main lobe over MSK
 Requires more power to transmit data than
many comparable modulation schemes
*
Binary sequence
GMSK modulated Signal
F ( )t
( )z t tI ( ) cos ( )= F
( )z t tQ ( ) sin ( )= F
5
1
0 5 10 15 20
-1
0
1
0 5 10 15 20
-1
0
1
t
0 5 10 15 20
1
-1
0 t
0 5 10 15 20
-5
0 t
0 5 10 15 20
-1
0 t
t
in rd
Modulation techniques
Modulation techniques
Modulation techniques
Modulation techniques
Modulation techniques
Modulation techniques

More Related Content

What's hot

Basics of analog communication system
Basics of analog communication systemBasics of analog communication system
Basics of analog communication systemswatihalunde
 
Analog communication
Analog communicationAnalog communication
Analog communicationPreston King
 
Diversity Techniques in Wireless Communication
Diversity Techniques in Wireless CommunicationDiversity Techniques in Wireless Communication
Diversity Techniques in Wireless CommunicationSahar Foroughi
 
3.2 modulation formats bpsk, qpsk, oqpsk,
3.2 modulation formats   bpsk, qpsk, oqpsk,3.2 modulation formats   bpsk, qpsk, oqpsk,
3.2 modulation formats bpsk, qpsk, oqpsk,JAIGANESH SEKAR
 
Pulse Modulation ppt
Pulse Modulation pptPulse Modulation ppt
Pulse Modulation pptsanjeev2419
 
Frequency-Shift Keying
Frequency-Shift KeyingFrequency-Shift Keying
Frequency-Shift KeyingJessie Rama
 
Modulation, Frequency Modulation, Phase Modulation, Amplitude Modulation
Modulation, Frequency Modulation, Phase Modulation, Amplitude ModulationModulation, Frequency Modulation, Phase Modulation, Amplitude Modulation
Modulation, Frequency Modulation, Phase Modulation, Amplitude ModulationWaqas Afzal
 
Ec 2401 wireless communication unit 2
Ec 2401 wireless communication   unit 2Ec 2401 wireless communication   unit 2
Ec 2401 wireless communication unit 2JAIGANESH SEKAR
 
Chap 1&2(history and intro) wireless communication
Chap 1&2(history and intro) wireless communicationChap 1&2(history and intro) wireless communication
Chap 1&2(history and intro) wireless communicationasadkhan1327
 
Rayleigh Fading Channel In Mobile Digital Communication System
Rayleigh Fading Channel In Mobile Digital Communication SystemRayleigh Fading Channel In Mobile Digital Communication System
Rayleigh Fading Channel In Mobile Digital Communication SystemOUM SAOKOSAL
 

What's hot (20)

Basics of analog communication system
Basics of analog communication systemBasics of analog communication system
Basics of analog communication system
 
OFDM
OFDMOFDM
OFDM
 
Lecture6 modulation
Lecture6 modulationLecture6 modulation
Lecture6 modulation
 
Analog communication
Analog communicationAnalog communication
Analog communication
 
Frequency Modulation
Frequency ModulationFrequency Modulation
Frequency Modulation
 
ASk,FSK,PSK
ASk,FSK,PSKASk,FSK,PSK
ASk,FSK,PSK
 
Amplitude modulation
Amplitude modulationAmplitude modulation
Amplitude modulation
 
Diversity Techniques in Wireless Communication
Diversity Techniques in Wireless CommunicationDiversity Techniques in Wireless Communication
Diversity Techniques in Wireless Communication
 
3.2 modulation formats bpsk, qpsk, oqpsk,
3.2 modulation formats   bpsk, qpsk, oqpsk,3.2 modulation formats   bpsk, qpsk, oqpsk,
3.2 modulation formats bpsk, qpsk, oqpsk,
 
Lecture 11
Lecture 11Lecture 11
Lecture 11
 
Spread spectrum modulation
Spread spectrum modulationSpread spectrum modulation
Spread spectrum modulation
 
Pulse Modulation ppt
Pulse Modulation pptPulse Modulation ppt
Pulse Modulation ppt
 
Frequency-Shift Keying
Frequency-Shift KeyingFrequency-Shift Keying
Frequency-Shift Keying
 
Modulation, Frequency Modulation, Phase Modulation, Amplitude Modulation
Modulation, Frequency Modulation, Phase Modulation, Amplitude ModulationModulation, Frequency Modulation, Phase Modulation, Amplitude Modulation
Modulation, Frequency Modulation, Phase Modulation, Amplitude Modulation
 
Multiple access techniques for wireless communications
Multiple access techniques for wireless communicationsMultiple access techniques for wireless communications
Multiple access techniques for wireless communications
 
Spread spectrum
Spread spectrumSpread spectrum
Spread spectrum
 
Ec 2401 wireless communication unit 2
Ec 2401 wireless communication   unit 2Ec 2401 wireless communication   unit 2
Ec 2401 wireless communication unit 2
 
Chap 1&2(history and intro) wireless communication
Chap 1&2(history and intro) wireless communicationChap 1&2(history and intro) wireless communication
Chap 1&2(history and intro) wireless communication
 
Digital modulation
Digital modulationDigital modulation
Digital modulation
 
Rayleigh Fading Channel In Mobile Digital Communication System
Rayleigh Fading Channel In Mobile Digital Communication SystemRayleigh Fading Channel In Mobile Digital Communication System
Rayleigh Fading Channel In Mobile Digital Communication System
 

Viewers also liked

Modulation types-amplitude,frequency,phase modulation,
Modulation types-amplitude,frequency,phase modulation,Modulation types-amplitude,frequency,phase modulation,
Modulation types-amplitude,frequency,phase modulation,gayatri suthar
 
Frequency modulation
Frequency modulationFrequency modulation
Frequency modulationAkanksha_Seth
 
Basics of signals data communication
Basics of signals data communicationBasics of signals data communication
Basics of signals data communicationSyed Bilal Zaidi
 
Modulation
ModulationModulation
Modulationsristykp
 
Analog modulation
Analog modulationAnalog modulation
Analog modulationAkash Soni
 
Investigation phase in development of MIS
Investigation phase in development of MISInvestigation phase in development of MIS
Investigation phase in development of MISSarvajeet Halder
 
5 investigating system requirements
5 investigating system requirements5 investigating system requirements
5 investigating system requirementsricardovigan
 
Different types of Modulation Techniques
Different types of Modulation TechniquesDifferent types of Modulation Techniques
Different types of Modulation TechniquesHimel Himo
 
Chapter 4 frequency modulation
Chapter 4 frequency modulationChapter 4 frequency modulation
Chapter 4 frequency modulationHattori Sidek
 
Analog and digital signals
Analog and digital signalsAnalog and digital signals
Analog and digital signalsteja reddy
 
Chapter 3 - Data and Signals
Chapter 3 - Data and SignalsChapter 3 - Data and Signals
Chapter 3 - Data and SignalsWayne Jones Jnr
 
System Analysis And Design Management Information System
System Analysis And Design Management Information SystemSystem Analysis And Design Management Information System
System Analysis And Design Management Information Systemnayanav
 
Modulation by sanjay
Modulation by sanjay Modulation by sanjay
Modulation by sanjay Sanjay Songra
 
Feasibility study
Feasibility study Feasibility study
Feasibility study mahaveer777
 
System Analysis and Design
System Analysis and DesignSystem Analysis and Design
System Analysis and DesignAamir Abbas
 

Viewers also liked (18)

Modulation types-amplitude,frequency,phase modulation,
Modulation types-amplitude,frequency,phase modulation,Modulation types-amplitude,frequency,phase modulation,
Modulation types-amplitude,frequency,phase modulation,
 
Frequency modulation
Frequency modulationFrequency modulation
Frequency modulation
 
Basics of signals data communication
Basics of signals data communicationBasics of signals data communication
Basics of signals data communication
 
Modulation
ModulationModulation
Modulation
 
Analog modulation
Analog modulationAnalog modulation
Analog modulation
 
Investigation phase in development of MIS
Investigation phase in development of MISInvestigation phase in development of MIS
Investigation phase in development of MIS
 
5 investigating system requirements
5 investigating system requirements5 investigating system requirements
5 investigating system requirements
 
Different types of Modulation Techniques
Different types of Modulation TechniquesDifferent types of Modulation Techniques
Different types of Modulation Techniques
 
Chapter 4 frequency modulation
Chapter 4 frequency modulationChapter 4 frequency modulation
Chapter 4 frequency modulation
 
Fm
FmFm
Fm
 
Analog and digital signals
Analog and digital signalsAnalog and digital signals
Analog and digital signals
 
Chapter 3 - Data and Signals
Chapter 3 - Data and SignalsChapter 3 - Data and Signals
Chapter 3 - Data and Signals
 
System Analysis And Design Management Information System
System Analysis And Design Management Information SystemSystem Analysis And Design Management Information System
System Analysis And Design Management Information System
 
Modulation by sanjay
Modulation by sanjay Modulation by sanjay
Modulation by sanjay
 
Feasibility study
Feasibility study Feasibility study
Feasibility study
 
Amplitude modulation
Amplitude modulationAmplitude modulation
Amplitude modulation
 
Feasibility Study
Feasibility StudyFeasibility Study
Feasibility Study
 
System Analysis and Design
System Analysis and DesignSystem Analysis and Design
System Analysis and Design
 

Similar to Modulation techniques

Digital modulation (19ES28) Ghulam Mueed
Digital modulation (19ES28) Ghulam Mueed Digital modulation (19ES28) Ghulam Mueed
Digital modulation (19ES28) Ghulam Mueed MueedAbbas
 
Amplitude shift keying
Amplitude shift keyingAmplitude shift keying
Amplitude shift keyingSunny Kumar
 
Analog Transmission
Analog TransmissionAnalog Transmission
Analog TransmissionShiraz316
 
Digital modulation
Digital modulationDigital modulation
Digital modulationAnkur Kumar
 
Digital modulation techniques
Digital modulation techniquesDigital modulation techniques
Digital modulation techniquesShriyaGautam3
 
Lecture digital modulation
Lecture digital modulationLecture digital modulation
Lecture digital modulationRonoh Kennedy
 
Digital to Analog conversion
Digital to Analog conversionDigital to Analog conversion
Digital to Analog conversionMariam Butt
 
Phase shift keying(PSK)
Phase shift keying(PSK)Phase shift keying(PSK)
Phase shift keying(PSK)MOHAN MOHAN
 
Ec 2401 wireless communication unit 3
Ec 2401 wireless communication   unit 3Ec 2401 wireless communication   unit 3
Ec 2401 wireless communication unit 3JAIGANESH SEKAR
 
Chapter7_Lathi_4thed_JAN_2021.pptx
Chapter7_Lathi_4thed_JAN_2021.pptxChapter7_Lathi_4thed_JAN_2021.pptx
Chapter7_Lathi_4thed_JAN_2021.pptxSubhanBihan1
 
Digital To Analog Conversion
Digital To Analog ConversionDigital To Analog Conversion
Digital To Analog ConversionSialkot
 
Phase shift keying Presentation
Phase shift keying PresentationPhase shift keying Presentation
Phase shift keying PresentationPavan Goswami
 
Chapter 2.1.pptx
Chapter 2.1.pptxChapter 2.1.pptx
Chapter 2.1.pptxTekle12
 
Chapter 2.1.pptx
Chapter 2.1.pptxChapter 2.1.pptx
Chapter 2.1.pptxTekle12
 
Modulation techniq of modem
Modulation techniq of modemModulation techniq of modem
Modulation techniq of modemAkshay Nagpurkar
 
Comparative Study and Performance Analysis of different Modulation Techniques...
Comparative Study and Performance Analysis of different Modulation Techniques...Comparative Study and Performance Analysis of different Modulation Techniques...
Comparative Study and Performance Analysis of different Modulation Techniques...Souvik Das
 
Digital modulation technique
Digital modulation techniqueDigital modulation technique
Digital modulation techniqueNidhi Baranwal
 
05 signal encodingtechniques
05 signal encodingtechniques05 signal encodingtechniques
05 signal encodingtechniquesOrbay Yeşil
 

Similar to Modulation techniques (20)

Digital modulation (19ES28) Ghulam Mueed
Digital modulation (19ES28) Ghulam Mueed Digital modulation (19ES28) Ghulam Mueed
Digital modulation (19ES28) Ghulam Mueed
 
Amplitude shift keying
Amplitude shift keyingAmplitude shift keying
Amplitude shift keying
 
Analog Transmission
Analog TransmissionAnalog Transmission
Analog Transmission
 
Digital modulation
Digital modulationDigital modulation
Digital modulation
 
Digital modulation techniques
Digital modulation techniquesDigital modulation techniques
Digital modulation techniques
 
Lecture digital modulation
Lecture digital modulationLecture digital modulation
Lecture digital modulation
 
Project report
Project reportProject report
Project report
 
Digital to Analog conversion
Digital to Analog conversionDigital to Analog conversion
Digital to Analog conversion
 
Phase shift keying(PSK)
Phase shift keying(PSK)Phase shift keying(PSK)
Phase shift keying(PSK)
 
Ec 2401 wireless communication unit 3
Ec 2401 wireless communication   unit 3Ec 2401 wireless communication   unit 3
Ec 2401 wireless communication unit 3
 
Chapter7_Lathi_4thed_JAN_2021.pptx
Chapter7_Lathi_4thed_JAN_2021.pptxChapter7_Lathi_4thed_JAN_2021.pptx
Chapter7_Lathi_4thed_JAN_2021.pptx
 
Digital To Analog Conversion
Digital To Analog ConversionDigital To Analog Conversion
Digital To Analog Conversion
 
Phase shift keying Presentation
Phase shift keying PresentationPhase shift keying Presentation
Phase shift keying Presentation
 
Chapter 2.1.pptx
Chapter 2.1.pptxChapter 2.1.pptx
Chapter 2.1.pptx
 
Chapter 2.1.pptx
Chapter 2.1.pptxChapter 2.1.pptx
Chapter 2.1.pptx
 
Modulation techniq of modem
Modulation techniq of modemModulation techniq of modem
Modulation techniq of modem
 
Comparative Study and Performance Analysis of different Modulation Techniques...
Comparative Study and Performance Analysis of different Modulation Techniques...Comparative Study and Performance Analysis of different Modulation Techniques...
Comparative Study and Performance Analysis of different Modulation Techniques...
 
Digital modulation technique
Digital modulation techniqueDigital modulation technique
Digital modulation technique
 
05 signal encodingtechniques
05 signal encodingtechniques05 signal encodingtechniques
05 signal encodingtechniques
 
UNIT-4 Baseband Digital Modulation.pdf
UNIT-4 Baseband Digital Modulation.pdfUNIT-4 Baseband Digital Modulation.pdf
UNIT-4 Baseband Digital Modulation.pdf
 

More from Sathish Kumar

LabVIEW Based Monitoring the Building in wireless communication
LabVIEW Based Monitoring the Building in wireless communicationLabVIEW Based Monitoring the Building in wireless communication
LabVIEW Based Monitoring the Building in wireless communicationSathish Kumar
 
7 layers of osi models
7 layers of osi models7 layers of osi models
7 layers of osi modelsSathish Kumar
 
Labview based wireless sensor for monitoring the building
Labview based wireless sensor for monitoring the buildingLabview based wireless sensor for monitoring the building
Labview based wireless sensor for monitoring the buildingSathish Kumar
 
V3 i4 ijertv3is040482
V3 i4 ijertv3is040482V3 i4 ijertv3is040482
V3 i4 ijertv3is040482Sathish Kumar
 

More from Sathish Kumar (10)

Home security
Home securityHome security
Home security
 
Interview questions
Interview questionsInterview questions
Interview questions
 
LabVIEW Based Monitoring the Building in wireless communication
LabVIEW Based Monitoring the Building in wireless communicationLabVIEW Based Monitoring the Building in wireless communication
LabVIEW Based Monitoring the Building in wireless communication
 
Labview Basics
Labview BasicsLabview Basics
Labview Basics
 
RSA ALGORITHM
RSA ALGORITHMRSA ALGORITHM
RSA ALGORITHM
 
7 layers of osi models
7 layers of osi models7 layers of osi models
7 layers of osi models
 
Labview based wireless sensor for monitoring the building
Labview based wireless sensor for monitoring the buildingLabview based wireless sensor for monitoring the building
Labview based wireless sensor for monitoring the building
 
Mysteries
MysteriesMysteries
Mysteries
 
V3 i4 ijertv3is040482
V3 i4 ijertv3is040482V3 i4 ijertv3is040482
V3 i4 ijertv3is040482
 
System hardware
System hardwareSystem hardware
System hardware
 

Recently uploaded

Mohs Scale of Hardness, Hardness Scale.pptx
Mohs Scale of Hardness, Hardness Scale.pptxMohs Scale of Hardness, Hardness Scale.pptx
Mohs Scale of Hardness, Hardness Scale.pptxKISHAN KUMAR
 
Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...
Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...
Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...amrabdallah9
 
Graphics Primitives and CG Display Devices
Graphics Primitives and CG Display DevicesGraphics Primitives and CG Display Devices
Graphics Primitives and CG Display DevicesDIPIKA83
 
دليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide Laboratory
دليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide Laboratoryدليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide Laboratory
دليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide LaboratoryBahzad5
 
ChatGPT-and-Generative-AI-Landscape Working of generative ai search
ChatGPT-and-Generative-AI-Landscape Working of generative ai searchChatGPT-and-Generative-AI-Landscape Working of generative ai search
ChatGPT-and-Generative-AI-Landscape Working of generative ai searchrohitcse52
 
Engineering Mechanics Chapter 5 Equilibrium of a Rigid Body
Engineering Mechanics  Chapter 5  Equilibrium of a Rigid BodyEngineering Mechanics  Chapter 5  Equilibrium of a Rigid Body
Engineering Mechanics Chapter 5 Equilibrium of a Rigid BodyAhmadHajasad2
 
Modelling Guide for Timber Structures - FPInnovations
Modelling Guide for Timber Structures - FPInnovationsModelling Guide for Timber Structures - FPInnovations
Modelling Guide for Timber Structures - FPInnovationsYusuf Yıldız
 
Renewable Energy & Entrepreneurship Workshop_21Feb2024.pdf
Renewable Energy & Entrepreneurship Workshop_21Feb2024.pdfRenewable Energy & Entrepreneurship Workshop_21Feb2024.pdf
Renewable Energy & Entrepreneurship Workshop_21Feb2024.pdfodunowoeminence2019
 
Gender Bias in Engineer, Honors 203 Project
Gender Bias in Engineer, Honors 203 ProjectGender Bias in Engineer, Honors 203 Project
Gender Bias in Engineer, Honors 203 Projectreemakb03
 
Technical Management of cement industry.pdf
Technical Management of cement industry.pdfTechnical Management of cement industry.pdf
Technical Management of cement industry.pdfMadan Karki
 
solar wireless electric vechicle charging system
solar wireless electric vechicle charging systemsolar wireless electric vechicle charging system
solar wireless electric vechicle charging systemgokuldongala
 
UNIT4_ESD_wfffffggggggggggggith_ARM.pptx
UNIT4_ESD_wfffffggggggggggggith_ARM.pptxUNIT4_ESD_wfffffggggggggggggith_ARM.pptx
UNIT4_ESD_wfffffggggggggggggith_ARM.pptxrealme6igamerr
 
CSR Managerial Round Questions and answers.pptx
CSR Managerial Round Questions and answers.pptxCSR Managerial Round Questions and answers.pptx
CSR Managerial Round Questions and answers.pptxssusera0771e
 
SATELITE COMMUNICATION UNIT 1 CEC352 REGULATION 2021 PPT BASICS OF SATELITE ....
SATELITE COMMUNICATION UNIT 1 CEC352 REGULATION 2021 PPT BASICS OF SATELITE ....SATELITE COMMUNICATION UNIT 1 CEC352 REGULATION 2021 PPT BASICS OF SATELITE ....
SATELITE COMMUNICATION UNIT 1 CEC352 REGULATION 2021 PPT BASICS OF SATELITE ....santhyamuthu1
 
Transforming Process Safety Management: Challenges, Benefits, and Transition ...
Transforming Process Safety Management: Challenges, Benefits, and Transition ...Transforming Process Safety Management: Challenges, Benefits, and Transition ...
Transforming Process Safety Management: Challenges, Benefits, and Transition ...soginsider
 
specification estimation and valuation of a building
specification estimation and valuation of a buildingspecification estimation and valuation of a building
specification estimation and valuation of a buildingswethasekhar5
 

Recently uploaded (20)

Mohs Scale of Hardness, Hardness Scale.pptx
Mohs Scale of Hardness, Hardness Scale.pptxMohs Scale of Hardness, Hardness Scale.pptx
Mohs Scale of Hardness, Hardness Scale.pptx
 
Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...
Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...
Strategies of Urban Morphologyfor Improving Outdoor Thermal Comfort and Susta...
 
Graphics Primitives and CG Display Devices
Graphics Primitives and CG Display DevicesGraphics Primitives and CG Display Devices
Graphics Primitives and CG Display Devices
 
دليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide Laboratory
دليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide Laboratoryدليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide Laboratory
دليل تجارب الاسفلت المختبرية - Asphalt Experiments Guide Laboratory
 
ChatGPT-and-Generative-AI-Landscape Working of generative ai search
ChatGPT-and-Generative-AI-Landscape Working of generative ai searchChatGPT-and-Generative-AI-Landscape Working of generative ai search
ChatGPT-and-Generative-AI-Landscape Working of generative ai search
 
Engineering Mechanics Chapter 5 Equilibrium of a Rigid Body
Engineering Mechanics  Chapter 5  Equilibrium of a Rigid BodyEngineering Mechanics  Chapter 5  Equilibrium of a Rigid Body
Engineering Mechanics Chapter 5 Equilibrium of a Rigid Body
 
Lecture 4 .pdf
Lecture 4                              .pdfLecture 4                              .pdf
Lecture 4 .pdf
 
Modelling Guide for Timber Structures - FPInnovations
Modelling Guide for Timber Structures - FPInnovationsModelling Guide for Timber Structures - FPInnovations
Modelling Guide for Timber Structures - FPInnovations
 
Renewable Energy & Entrepreneurship Workshop_21Feb2024.pdf
Renewable Energy & Entrepreneurship Workshop_21Feb2024.pdfRenewable Energy & Entrepreneurship Workshop_21Feb2024.pdf
Renewable Energy & Entrepreneurship Workshop_21Feb2024.pdf
 
計劃趕得上變化
計劃趕得上變化計劃趕得上變化
計劃趕得上變化
 
Gender Bias in Engineer, Honors 203 Project
Gender Bias in Engineer, Honors 203 ProjectGender Bias in Engineer, Honors 203 Project
Gender Bias in Engineer, Honors 203 Project
 
Présentation IIRB 2024 Marine Cordonnier.pdf
Présentation IIRB 2024 Marine Cordonnier.pdfPrésentation IIRB 2024 Marine Cordonnier.pdf
Présentation IIRB 2024 Marine Cordonnier.pdf
 
Technical Management of cement industry.pdf
Technical Management of cement industry.pdfTechnical Management of cement industry.pdf
Technical Management of cement industry.pdf
 
solar wireless electric vechicle charging system
solar wireless electric vechicle charging systemsolar wireless electric vechicle charging system
solar wireless electric vechicle charging system
 
UNIT4_ESD_wfffffggggggggggggith_ARM.pptx
UNIT4_ESD_wfffffggggggggggggith_ARM.pptxUNIT4_ESD_wfffffggggggggggggith_ARM.pptx
UNIT4_ESD_wfffffggggggggggggith_ARM.pptx
 
CSR Managerial Round Questions and answers.pptx
CSR Managerial Round Questions and answers.pptxCSR Managerial Round Questions and answers.pptx
CSR Managerial Round Questions and answers.pptx
 
Présentation IIRB 2024 Chloe Dufrane.pdf
Présentation IIRB 2024 Chloe Dufrane.pdfPrésentation IIRB 2024 Chloe Dufrane.pdf
Présentation IIRB 2024 Chloe Dufrane.pdf
 
SATELITE COMMUNICATION UNIT 1 CEC352 REGULATION 2021 PPT BASICS OF SATELITE ....
SATELITE COMMUNICATION UNIT 1 CEC352 REGULATION 2021 PPT BASICS OF SATELITE ....SATELITE COMMUNICATION UNIT 1 CEC352 REGULATION 2021 PPT BASICS OF SATELITE ....
SATELITE COMMUNICATION UNIT 1 CEC352 REGULATION 2021 PPT BASICS OF SATELITE ....
 
Transforming Process Safety Management: Challenges, Benefits, and Transition ...
Transforming Process Safety Management: Challenges, Benefits, and Transition ...Transforming Process Safety Management: Challenges, Benefits, and Transition ...
Transforming Process Safety Management: Challenges, Benefits, and Transition ...
 
specification estimation and valuation of a building
specification estimation and valuation of a buildingspecification estimation and valuation of a building
specification estimation and valuation of a building
 

Modulation techniques

  • 1. *
  • 2. We use the term modulation to refer to changes made in a carrier -according to the information being sent Modulation takes two inputs -a carrier -and a signal
  • 3. * MSK FSK ASK
  • 5. * Shift Keying To distinguish between analog and digital modulation -We use the term shift keying rather than modulation
  • 7. *  ASK is the abbreviation of Amplitude Shift Keying  Ask is called On-Off Keying.  The simplest and most common form of operate as a switch.
  • 8. *  It is Abbreviated as Frequency shift keying  Values represented by different frequencies (near carrier)  Less susceptible to error than ASK  Typically used up to 1200bps on voice grade lines  High frequency radio  Even higher frequency on LANs using co-ax
  • 9. * Amplitude and frequency modulations require at least one cycle of a carrier wave to send a single bit unless a special encoding scheme is used The number of bits sent per unit time can be increased if the encoding scheme permits multiple bits to be encoded in a single cycle of the carrier Data communications systems often use techniques that can send more bits PSK changes the phase of the carrier wave abruptly each such change is called a phase shift * Phase of carrier signal is shifted to represent data
  • 10. Quadrature amplitude modulation is a combination of ASK and PSK. Note
  • 11. * To send more than one bit at a time It is possible to send two bits on one wave by defining four different amplitudes. The same approach can be used for frequency and phase modulation.
  • 13. In practice, the maximum number of bits that can be sent with any one of these techniques is about five bits. The solution is to combine modulation techniques. One popular technique is quadrature amplitude modulation (QAM) involves splitting the signal into eight different phases, and two different amplitude for a total of 16 different possible values, giving us lg(16) or 4 bits per value.
  • 14. *
  • 15. *
  • 16. *Minimum Shift Keying MSK is a variant of OQPSK The rectangular symbol pulse is replaced by a half cycle sinusoidal symbol pulse. MSK provides a constant envelope signal which has it’s phase continuous at all times including the interbit switching times.  In MSK, also the phase shifts can be detected with an I or Q modulator.  At even numbered symbols, the polarity of I channel conveys the transmitted data and at odd numbered symbols the polarity of Q channel conveys the data.  A phase shift of + 90 degrees represents a data bit equal to 1 and a phase shift of –90 degrees represents a data bit equal to zero
  • 17. It possesses properties such as: constant envelope spectral efficiency good BER performance self-synchronizing capability. MSK PROPERTIES
  • 18. *
  • 19. * • Gaussian Minimum Shift Keying • Modulation scheme used in GSM • Bandwidth-time product • Describes the amount the symbols overlap • BT = 0.3 for GSM networks • Good spectral efficiency • At the expense of some inter-symbol interference (ISI • Data rate: 270.8 kbps
  • 20. * • GMSK is based on MSK • Minimum Shift Keying • Linear phase changes • Spectrally efficient • At baseband, bit transitions are represented by ½ cycle sinusoid
  • 21. *  Improved spectral efficiency  Power Spectral Density  Reduced main lobe over MSK  Requires more power to transmit data than many comparable modulation schemes
  • 22. * Binary sequence GMSK modulated Signal F ( )t ( )z t tI ( ) cos ( )= F ( )z t tQ ( ) sin ( )= F 5 1 0 5 10 15 20 -1 0 1 0 5 10 15 20 -1 0 1 t 0 5 10 15 20 1 -1 0 t 0 5 10 15 20 -5 0 t 0 5 10 15 20 -1 0 t t in rd