The document discusses analog communications and the Analog Communications course at Matrusri Engineering College. It includes:
- Course objectives like analyzing analog communication systems, understanding generation and detection of analog modulation techniques, and analyzing noise performance.
- Course outcomes like describing modulation/demodulation schemes and comparing analog modulation schemes.
- A syllabus covering topics like linear modulation schemes, angle modulation schemes, analog pulse modulation schemes, transmitters and receivers, and noise sources and types.
- Details of the course include lesson plans with topics, outcomes, textbooks, and introductions to modules on concepts like amplitude modulation and its time/frequency domain representations.
This document provides an overview of a communication systems course taught by Ass. Prof. Ibrar Ullah. The course objectives are to develop basic concepts of communication systems using the textbook "Modern Digital And Analog Communication Systems". Students will be evaluated based on homework, tests, quizzes, and a final exam. Key topics covered include analog versus digital communication, modulation techniques, and the relationship between signal-to-noise ratio, channel bandwidth, and rate of communication.
Phase modulation (PM) is a form of modulation where information is represented by variations in the instantaneous phase of a carrier wave. The phase angle of the complex envelope is changed in direct proportion to the message signal. PM can be considered a special case of FM where the carrier frequency modulation is given by the time derivative of the phase modulation. The bandwidth of PM for a single sinusoidal signal is approximately equal to the modulation index multiplied by the carrier frequency.
This document discusses frequency modulation (FM). It begins by defining the angle of a carrier signal and how that angle can be varied to achieve FM or phase modulation. It then provides key details about FM, including that the message signal controls the carrier frequency. The FM signal equation is presented using Bessel functions. Important parameters like modulation index and frequency deviation are defined. Signal waveforms are shown for different input signals. The spectrum of an FM signal is discussed, including the Bessel coefficients and significant sidebands. Narrowband and wideband FM are differentiated. An example of VHF/FM radio transmission parameters is provided. Finally, power in FM signals is addressed.
Angle modulation techniques such as frequency modulation (FM) and phase modulation (PM) were introduced. FM varies the carrier frequency according to the message signal, while PM varies the carrier phase. The chapter covered the concepts of instantaneous frequency, bandwidth of angle modulated signals, generation of FM signals through direct and indirect methods, and demodulation of FM signals using discriminators and phase-locked loops. Key advantages of FM over AM include improved noise immunity and resistance to interference at the cost of increased transmission bandwidth.
An antenna converts electric power into radio waves and vice versa. There are two main categories of antennas - omnidirectional antennas that radiate in all directions, and directional antennas that preferentially radiate in a particular direction. Key parameters that define antennas include frequency, directivity, efficiency, gain, wavelength, and polarization. Common types of antennas discussed are Yagi antennas, log-periodic antennas, horn antennas, loop antennas, and parabolic antennas.
This document discusses various types of pulse modulation techniques used in analog and digital communication systems. It begins by defining pulse amplitude modulation (PAM) and describing how the amplitude of pulses varies proportionally to the message signal. It then discusses different types of PAM based on the sampling technique used - ideal, natural, and flat-top sampling. Flat-top sampling uses sample-and-hold circuits and can introduce amplitude distortion known as the aperture effect. The document also covers pulse width modulation (PWM), pulse position modulation (PPM), pulse code modulation (PCM), delta modulation (DM), and their advantages. It explains the sampling theorem and proves it through Fourier analysis. Finally, it discusses bandwidth requirements, transmission, drawbacks
1) Modulation involves changing characteristics of a high-frequency carrier signal according to an information signal. This allows signal transmission over long distances and multiple signals over the same channel.
2) The main modulation types are amplitude modulation (AM), which changes amplitude; frequency modulation (FM), which changes frequency; and phase modulation (PM), which changes phase.
3) AM is the simplest form and varies the carrier amplitude by the information signal. It has advantages of simplicity but is inefficient in power and bandwidth usage, and susceptible to noise.
This document provides an overview of a communication systems course taught by Ass. Prof. Ibrar Ullah. The course objectives are to develop basic concepts of communication systems using the textbook "Modern Digital And Analog Communication Systems". Students will be evaluated based on homework, tests, quizzes, and a final exam. Key topics covered include analog versus digital communication, modulation techniques, and the relationship between signal-to-noise ratio, channel bandwidth, and rate of communication.
Phase modulation (PM) is a form of modulation where information is represented by variations in the instantaneous phase of a carrier wave. The phase angle of the complex envelope is changed in direct proportion to the message signal. PM can be considered a special case of FM where the carrier frequency modulation is given by the time derivative of the phase modulation. The bandwidth of PM for a single sinusoidal signal is approximately equal to the modulation index multiplied by the carrier frequency.
This document discusses frequency modulation (FM). It begins by defining the angle of a carrier signal and how that angle can be varied to achieve FM or phase modulation. It then provides key details about FM, including that the message signal controls the carrier frequency. The FM signal equation is presented using Bessel functions. Important parameters like modulation index and frequency deviation are defined. Signal waveforms are shown for different input signals. The spectrum of an FM signal is discussed, including the Bessel coefficients and significant sidebands. Narrowband and wideband FM are differentiated. An example of VHF/FM radio transmission parameters is provided. Finally, power in FM signals is addressed.
Angle modulation techniques such as frequency modulation (FM) and phase modulation (PM) were introduced. FM varies the carrier frequency according to the message signal, while PM varies the carrier phase. The chapter covered the concepts of instantaneous frequency, bandwidth of angle modulated signals, generation of FM signals through direct and indirect methods, and demodulation of FM signals using discriminators and phase-locked loops. Key advantages of FM over AM include improved noise immunity and resistance to interference at the cost of increased transmission bandwidth.
An antenna converts electric power into radio waves and vice versa. There are two main categories of antennas - omnidirectional antennas that radiate in all directions, and directional antennas that preferentially radiate in a particular direction. Key parameters that define antennas include frequency, directivity, efficiency, gain, wavelength, and polarization. Common types of antennas discussed are Yagi antennas, log-periodic antennas, horn antennas, loop antennas, and parabolic antennas.
This document discusses various types of pulse modulation techniques used in analog and digital communication systems. It begins by defining pulse amplitude modulation (PAM) and describing how the amplitude of pulses varies proportionally to the message signal. It then discusses different types of PAM based on the sampling technique used - ideal, natural, and flat-top sampling. Flat-top sampling uses sample-and-hold circuits and can introduce amplitude distortion known as the aperture effect. The document also covers pulse width modulation (PWM), pulse position modulation (PPM), pulse code modulation (PCM), delta modulation (DM), and their advantages. It explains the sampling theorem and proves it through Fourier analysis. Finally, it discusses bandwidth requirements, transmission, drawbacks
1) Modulation involves changing characteristics of a high-frequency carrier signal according to an information signal. This allows signal transmission over long distances and multiple signals over the same channel.
2) The main modulation types are amplitude modulation (AM), which changes amplitude; frequency modulation (FM), which changes frequency; and phase modulation (PM), which changes phase.
3) AM is the simplest form and varies the carrier amplitude by the information signal. It has advantages of simplicity but is inefficient in power and bandwidth usage, and susceptible to noise.
Transmitters and receivers were discussed. Transmitters were classified based on modulation type, service, frequency range, and power. The key components of a transmitter were identified as the modulator, RF oscillator, and power amplifier. Their basic functions are modulation, carrier generation, and amplification. Low-level and high-level AM transmitters were described. Low-level transmitters modulate at low power levels then amplify, while high-level transmitters modulate directly at high power for better efficiency. Audio processing before modulation was also outlined.
The document discusses modulation and amplitude modulation. It defines modulation as varying characteristics of a carrier signal in accordance with a modulation wave. Amplitude modulation varies the amplitude of a carrier signal proportionally to the instantaneous value of a modulating signal. The amplitude modulated signal is made up of the carrier signal, modulating signal, and sidebands containing the information. The modulation index indicates the ratio between the modulating signal and carrier amplitudes. Amplitude modulation has applications in broadcasting and communications.
Modulation
In the modulation process, some characteristic of a high-frequency carrier signal (bandpass), is changed according to the instantaneous amplitude of the information (baseband) signal.
Pulse modulation techniques can encode an analog signal for transmission. This document discusses several techniques including:
- Pulse-amplitude modulation (PAM) which varies pulse amplitudes based on sample values of the message signal.
- Pulse code modulation (PCM) which assigns a binary code to each analog sample. PCM is commonly used in digital communications systems.
- Delta modulation which transmits one bit per sample indicating if the current sample is more positive or negative than the previous. It requires higher sampling rates than PCM for equal quality.
Diversity Techniques in Wireless CommunicationSahar Foroughi
This document discusses diversity techniques for wireless communication, including cooperative diversity. It begins by introducing wireless systems and the impairments they face like fading. It then covers various diversity techniques like space, frequency, and time diversity that provide multiple transmission paths to reduce fading. Cooperative diversity is described as allowing single-antenna devices to achieve MIMO-like benefits by sharing antennas. The document outlines cooperative transmission protocols and challenges at different network layers in implementing cooperation. In conclusion, diversity techniques improve performance by providing multiple signal replicas to overcome fading, while cooperation enables reliability and throughput gains with challenges to address across protocol layers.
Modulation involves adding information to a carrier signal. Digital modulation provides more information capacity, compatibility with digital services, higher security, better quality, and faster availability compared to analog modulation. Common digital modulation techniques include amplitude-shift keying (ASK), frequency-shift keying (FSK), phase-shift keying (PSK) and their variants. PSK techniques include binary PSK (BPSK), quadrature PSK (QPSK) and differential PSK (DPSK). QPSK transmits twice as much data as BPSK within the same bandwidth. DPSK avoids the need for a coherent reference signal at the receiver. Key considerations in modulation include power efficiency, bandwidth efficiency and bit error rate.
Fm demodulation using zero crossing detectormpsrekha83
This document discusses FM demodulation using a zero crossing detector. It contains a block diagram of a zero crossing detector system consisting of a zero crossing detector, pulse generator, DC block, and low pass filter. It explains that the zero crossing detector operates by measuring the time difference between adjacent zero crossings of the FM wave, which is related to the instantaneous frequency and can be used to recover the message signal. It notes the advantages and disadvantages of this technique.
This PowerPoint presentation discusses amplitude modulation (AM). It defines AM as a process where the amplitude of a carrier signal is altered according to information in a message signal. Common applications of AM include broadcasting and aircraft communications. The presentation explains key aspects of AM signals such as the carrier signal, modulating signal, envelope, and modulation index. It also covers bandwidth, power measurements, and advantages of AM such as reducing antenna height and increasing communication range.
This document discusses frequency modulation (FM) and its types: phase modulation and frequency modulation. It describes the key characteristics of FM including its constant amplitude, higher signal-to-noise ratio, and infinite bandwidth. FM is classified as narrowband FM (NBFM) or wideband FM (WBFM) based on the modulation index. The document also covers pre-emphasis and de-emphasis circuits, methods for generating NBFM and WBFM signals including the direct and indirect (Armstrong's) methods.
Details: https://electronicsembeddedworld.blogspot.com/2018/06/performance-management-mcq.html
FM demodulation involves changing the frequency variations in a signal into amplitude variations at baseband, e.g. audio. There are several techniques and circuits that can be used each with its own advantages and disadvantages.
In any radio that is designed to receive frequency modulated signals there is some form of FM demodulator or detector. This circuit takes in frequency modulated RF signals and takes the modulation from the signal to output only the modulation that had been applied at the transmitter.
There are several types of FM detector / demodulator that can be used. Some types were more popular in the days when radios were made from discrete devices, but nowadays the PLL based detector and quadrature / coincidence detectors are the most widely used as they lend themselves to being incorporated into integrated circuits very easily...
Single Sideband Suppressed Carrier (SSB-SC)Ridwanul Hoque
Single-sideband suppressed carrier (SSB-SC) modulation improves spectral efficiency by transmitting only one sideband. It requires a bandwidth equal to the signal bandwidth. SSB-SC can be detected coherently using multiplication by the carrier. Quadrature amplitude modulation (QAM) transmits two baseband signals over the same bandwidth using in-phase and quadrature carriers that are 90 degrees out of phase. Vestigial sideband (VSB) modulation is a compromise between DSB and SSB that inherits advantages of both while requiring only slightly greater bandwidth than SSB. It is used for broadcast television transmission.
This document discusses amplitude modulation (AM) used in radio broadcasting. It describes the principles of AM including: how the carrier amplitude changes proportionally to the modulation signal, its advantages of simple circuits and use for audio/video broadcasting, and its disadvantages of noise and inefficient power use. Key aspects of AM include: the carrier signal combined with the modulating signal in the modulator, which produces an AM envelope waveform and sidebands around the carrier frequency. The bandwidth of an AM signal is equal to twice the highest modulating frequency.
The document discusses amplitude modulation (AM), which is the simplest and earliest form of modulation. AM involves varying the amplitude of a carrier signal based on the instantaneous amplitude of an information signal. It describes the basic principles of AM, including modulation index and different types of AM such as double sideband suppressed carrier AM and single sideband AM. Advantages of AM include its simplicity of implementation, while disadvantages include inefficiency in power and bandwidth usage and susceptibility to noise.
The document discusses digital communication systems and outlines topics that will be covered, including digital data communication, multiplexing techniques, digital modulation and demodulation, and performance comparisons of modulation schemes. The objectives are to provide an overview of communication systems and concepts, discuss digital transmission methods and modulation types, and enable students to design simple communication systems and discuss industry trends.
FM transmitters and receivers are used for sending and receiving FM signals. Transmitters modulate a carrier wave with an audio signal to generate an FM signal, which is transmitted through a band. Receivers receive the modulated signal, demodulate it to extract the original audio signal. FM offers advantages over AM like noise reduction, improved fidelity, and more efficient power use, though it requires more complex circuits and a larger bandwidth. Applications of FM include radio broadcasting, mobile radio, TV sound, and cellular/satellite communication.
Pulse-amplitude modulation (PAM) encodes message information in the amplitude of signal pulses. A PAM-4 modulator takes two bits at a time and maps them to one of four amplitude levels, such as -3V, -1V, 1V, and 3V. Demodulation detects the amplitude level of each symbol period. PAM is widely used for baseband digital data transmission, though other modulation methods are now more common.
This document discusses various types of pulse modulation techniques. It describes analog pulse modulation techniques including pulse amplitude modulation (PAM), pulse duration modulation (PDM), and pulse position modulation (PPM). It also covers digital pulse modulation techniques such as pulse code modulation (PCM) and delta modulation. For each technique, it provides details on the generator, waveform, and advantages and disadvantages. In conclusion, it summarizes that different pulse modulation techniques were discussed along with how they are transmitted and their waveforms. It also reviews the advantages and disadvantages of these modulation methods.
This document discusses various diversity techniques used in wireless communications to combat fading. It describes types of diversity including time, frequency, multiuser, and space diversity. It also outlines combining techniques such as selection combining, maximal ratio combining and equal gain combining that are used to improve the signal by combining signals from multiple diversity branches. The document concludes by discussing multiple input multiple output (MIMO) systems and orthogonal frequency division multiple access (OFDMA) schemes that exploit diversity and multiuser diversity.
This document provides information about the Analog Communications course offered at Matrusri Engineering College. It includes the course objectives, outcomes, syllabus, lesson plan and introduction. The key points are:
- The course objectives are to analyze analog communication systems and understand various analog modulation techniques, noise performance and AM/FM receivers.
- The syllabus covers topics like linear modulation schemes, angle modulation schemes, transmitters and receivers, noise sources and types, and analog pulse modulation schemes.
- The lesson plan provides details of topics to be covered in each unit, including frequency modulation, phase modulation, and modulation/demodulation techniques.
- The introductions provide an overview of the topics to be discussed in each
The document discusses the objectives, outcomes, syllabus, and lesson plan for the Analog Communications course at Matrusri Engineering College. The key topics covered in the course include linear and nonlinear modulation techniques, amplitude modulation, angle modulation, pulse modulation schemes, transmitter and receiver design. The course aims to analyze analog communication systems and various analog modulation techniques, as well as noise performance and the structures of AM and FM transmitters and receivers.
Transmitters and receivers were discussed. Transmitters were classified based on modulation type, service, frequency range, and power. The key components of a transmitter were identified as the modulator, RF oscillator, and power amplifier. Their basic functions are modulation, carrier generation, and amplification. Low-level and high-level AM transmitters were described. Low-level transmitters modulate at low power levels then amplify, while high-level transmitters modulate directly at high power for better efficiency. Audio processing before modulation was also outlined.
The document discusses modulation and amplitude modulation. It defines modulation as varying characteristics of a carrier signal in accordance with a modulation wave. Amplitude modulation varies the amplitude of a carrier signal proportionally to the instantaneous value of a modulating signal. The amplitude modulated signal is made up of the carrier signal, modulating signal, and sidebands containing the information. The modulation index indicates the ratio between the modulating signal and carrier amplitudes. Amplitude modulation has applications in broadcasting and communications.
Modulation
In the modulation process, some characteristic of a high-frequency carrier signal (bandpass), is changed according to the instantaneous amplitude of the information (baseband) signal.
Pulse modulation techniques can encode an analog signal for transmission. This document discusses several techniques including:
- Pulse-amplitude modulation (PAM) which varies pulse amplitudes based on sample values of the message signal.
- Pulse code modulation (PCM) which assigns a binary code to each analog sample. PCM is commonly used in digital communications systems.
- Delta modulation which transmits one bit per sample indicating if the current sample is more positive or negative than the previous. It requires higher sampling rates than PCM for equal quality.
Diversity Techniques in Wireless CommunicationSahar Foroughi
This document discusses diversity techniques for wireless communication, including cooperative diversity. It begins by introducing wireless systems and the impairments they face like fading. It then covers various diversity techniques like space, frequency, and time diversity that provide multiple transmission paths to reduce fading. Cooperative diversity is described as allowing single-antenna devices to achieve MIMO-like benefits by sharing antennas. The document outlines cooperative transmission protocols and challenges at different network layers in implementing cooperation. In conclusion, diversity techniques improve performance by providing multiple signal replicas to overcome fading, while cooperation enables reliability and throughput gains with challenges to address across protocol layers.
Modulation involves adding information to a carrier signal. Digital modulation provides more information capacity, compatibility with digital services, higher security, better quality, and faster availability compared to analog modulation. Common digital modulation techniques include amplitude-shift keying (ASK), frequency-shift keying (FSK), phase-shift keying (PSK) and their variants. PSK techniques include binary PSK (BPSK), quadrature PSK (QPSK) and differential PSK (DPSK). QPSK transmits twice as much data as BPSK within the same bandwidth. DPSK avoids the need for a coherent reference signal at the receiver. Key considerations in modulation include power efficiency, bandwidth efficiency and bit error rate.
Fm demodulation using zero crossing detectormpsrekha83
This document discusses FM demodulation using a zero crossing detector. It contains a block diagram of a zero crossing detector system consisting of a zero crossing detector, pulse generator, DC block, and low pass filter. It explains that the zero crossing detector operates by measuring the time difference between adjacent zero crossings of the FM wave, which is related to the instantaneous frequency and can be used to recover the message signal. It notes the advantages and disadvantages of this technique.
This PowerPoint presentation discusses amplitude modulation (AM). It defines AM as a process where the amplitude of a carrier signal is altered according to information in a message signal. Common applications of AM include broadcasting and aircraft communications. The presentation explains key aspects of AM signals such as the carrier signal, modulating signal, envelope, and modulation index. It also covers bandwidth, power measurements, and advantages of AM such as reducing antenna height and increasing communication range.
This document discusses frequency modulation (FM) and its types: phase modulation and frequency modulation. It describes the key characteristics of FM including its constant amplitude, higher signal-to-noise ratio, and infinite bandwidth. FM is classified as narrowband FM (NBFM) or wideband FM (WBFM) based on the modulation index. The document also covers pre-emphasis and de-emphasis circuits, methods for generating NBFM and WBFM signals including the direct and indirect (Armstrong's) methods.
Details: https://electronicsembeddedworld.blogspot.com/2018/06/performance-management-mcq.html
FM demodulation involves changing the frequency variations in a signal into amplitude variations at baseband, e.g. audio. There are several techniques and circuits that can be used each with its own advantages and disadvantages.
In any radio that is designed to receive frequency modulated signals there is some form of FM demodulator or detector. This circuit takes in frequency modulated RF signals and takes the modulation from the signal to output only the modulation that had been applied at the transmitter.
There are several types of FM detector / demodulator that can be used. Some types were more popular in the days when radios were made from discrete devices, but nowadays the PLL based detector and quadrature / coincidence detectors are the most widely used as they lend themselves to being incorporated into integrated circuits very easily...
Single Sideband Suppressed Carrier (SSB-SC)Ridwanul Hoque
Single-sideband suppressed carrier (SSB-SC) modulation improves spectral efficiency by transmitting only one sideband. It requires a bandwidth equal to the signal bandwidth. SSB-SC can be detected coherently using multiplication by the carrier. Quadrature amplitude modulation (QAM) transmits two baseband signals over the same bandwidth using in-phase and quadrature carriers that are 90 degrees out of phase. Vestigial sideband (VSB) modulation is a compromise between DSB and SSB that inherits advantages of both while requiring only slightly greater bandwidth than SSB. It is used for broadcast television transmission.
This document discusses amplitude modulation (AM) used in radio broadcasting. It describes the principles of AM including: how the carrier amplitude changes proportionally to the modulation signal, its advantages of simple circuits and use for audio/video broadcasting, and its disadvantages of noise and inefficient power use. Key aspects of AM include: the carrier signal combined with the modulating signal in the modulator, which produces an AM envelope waveform and sidebands around the carrier frequency. The bandwidth of an AM signal is equal to twice the highest modulating frequency.
The document discusses amplitude modulation (AM), which is the simplest and earliest form of modulation. AM involves varying the amplitude of a carrier signal based on the instantaneous amplitude of an information signal. It describes the basic principles of AM, including modulation index and different types of AM such as double sideband suppressed carrier AM and single sideband AM. Advantages of AM include its simplicity of implementation, while disadvantages include inefficiency in power and bandwidth usage and susceptibility to noise.
The document discusses digital communication systems and outlines topics that will be covered, including digital data communication, multiplexing techniques, digital modulation and demodulation, and performance comparisons of modulation schemes. The objectives are to provide an overview of communication systems and concepts, discuss digital transmission methods and modulation types, and enable students to design simple communication systems and discuss industry trends.
FM transmitters and receivers are used for sending and receiving FM signals. Transmitters modulate a carrier wave with an audio signal to generate an FM signal, which is transmitted through a band. Receivers receive the modulated signal, demodulate it to extract the original audio signal. FM offers advantages over AM like noise reduction, improved fidelity, and more efficient power use, though it requires more complex circuits and a larger bandwidth. Applications of FM include radio broadcasting, mobile radio, TV sound, and cellular/satellite communication.
Pulse-amplitude modulation (PAM) encodes message information in the amplitude of signal pulses. A PAM-4 modulator takes two bits at a time and maps them to one of four amplitude levels, such as -3V, -1V, 1V, and 3V. Demodulation detects the amplitude level of each symbol period. PAM is widely used for baseband digital data transmission, though other modulation methods are now more common.
This document discusses various types of pulse modulation techniques. It describes analog pulse modulation techniques including pulse amplitude modulation (PAM), pulse duration modulation (PDM), and pulse position modulation (PPM). It also covers digital pulse modulation techniques such as pulse code modulation (PCM) and delta modulation. For each technique, it provides details on the generator, waveform, and advantages and disadvantages. In conclusion, it summarizes that different pulse modulation techniques were discussed along with how they are transmitted and their waveforms. It also reviews the advantages and disadvantages of these modulation methods.
This document discusses various diversity techniques used in wireless communications to combat fading. It describes types of diversity including time, frequency, multiuser, and space diversity. It also outlines combining techniques such as selection combining, maximal ratio combining and equal gain combining that are used to improve the signal by combining signals from multiple diversity branches. The document concludes by discussing multiple input multiple output (MIMO) systems and orthogonal frequency division multiple access (OFDMA) schemes that exploit diversity and multiuser diversity.
This document provides information about the Analog Communications course offered at Matrusri Engineering College. It includes the course objectives, outcomes, syllabus, lesson plan and introduction. The key points are:
- The course objectives are to analyze analog communication systems and understand various analog modulation techniques, noise performance and AM/FM receivers.
- The syllabus covers topics like linear modulation schemes, angle modulation schemes, transmitters and receivers, noise sources and types, and analog pulse modulation schemes.
- The lesson plan provides details of topics to be covered in each unit, including frequency modulation, phase modulation, and modulation/demodulation techniques.
- The introductions provide an overview of the topics to be discussed in each
The document discusses the objectives, outcomes, syllabus, and lesson plan for the Analog Communications course at Matrusri Engineering College. The key topics covered in the course include linear and nonlinear modulation techniques, amplitude modulation, angle modulation, pulse modulation schemes, transmitter and receiver design. The course aims to analyze analog communication systems and various analog modulation techniques, as well as noise performance and the structures of AM and FM transmitters and receivers.
The sampling theorem can be explained as follows:
1. According to the sampling theorem, a continuous-time signal x(t) that has no frequency components higher than B Hz can be perfectly reconstructed from its samples if it is sampled at a frequency fs that is greater than 2B samples/second. This minimum sampling frequency fs is called the Nyquist rate.
2. The sampling theorem states that for a bandlimited signal with maximum frequency B Hz, the signal must be sampled at a frequency fs that is greater than 2B samples/second in order to avoid aliasing and allow perfect reconstruction of the original continuous-time signal from the samples.
3. Aliasing occurs when the signal is sampled at a rate lower than
Communication Theory-1 Project || Single Side Band Modulation using Filtering...rameshreddybattini
Communication Theory-1 Project || Single Side Band Modulation using Filtering Method and Synchronous Demodulation in the Presence of Noise || Using Matlab Code
Cs2204 analog & digital communication question bankparthi_arjun
This document contains a syllabus for the subject "Analog and Digital Communication". It includes 5 units:
1. Fundamentals of Analog Communication covering AM modulation, bandwidth, and angle modulation.
2. Digital Communication including Shannon limit, digital modulation techniques like FSK, PSK, and QAM.
3. Digital Transmission covering pulse modulation techniques like PCM, DPCM, and eye patterns.
4. Data Communications covering standards, circuits, error control codes and interfaces.
5. Spread Spectrum and Multiple Access covering DS-SS, FH-SS, TDMA, CDMA and speech coding for wireless systems.
The syllabus provides learning outcomes for each unit and
The document discusses analog communication systems and amplitude modulation. It introduces key concepts such as elements of a communication system including the information source, transmitter, channel, and receiver. It describes amplitude modulation where the amplitude of a carrier wave is varied in accordance with the modulating signal. Common modulation techniques like DSB-SC and generation methods like using a square law or switching modulator are summarized. Detection or demodulation of the AM signal using detectors like square law, envelope, and rectifier are also outlined.
This task involves generating a single tone SSB modulated signal. A modulating signal m(t) = cos(1000πt) and carrier c(t) = cos(104πt) are used. The SSB modulated signal is generated using the filtering method. The USB and LSB spectra are identified, with the USB spectrum occupying frequencies above the carrier and the LSB spectrum below. The maximum and minimum envelope amplitudes and power in the USB, LSB and modulated signals are determined. Simulation results and plots of the signals and their spectra are presented.
This document contains a syllabus for a Communication Electronics course. The syllabus covers 6 units:
1) Amplitude Modulation
2) Angle Modulation
3) Pulse Modulation
4) Noise
5) AM and FM Receivers
6) Broadband Communication Links and Multiplexing
The syllabus provides an overview of the key topics that will be covered in each unit, including the concepts, mathematical analysis, generation methods, and applications of various modulation techniques. It also lists recommended textbooks and reference books for the course.
The document provides the syllabus for the third year second semester of the B.Tech ECE program at JNTU Hyderabad. It includes details of 9 courses that are part of the semester. The courses cover topics like Antennas and Propagation, Digital Signal Processing, VLSI Design, and Object Oriented Programming through Java. The syllabus provides course objectives, outcomes and unit-wise topics for each course. It also lists the textbooks and references for further reading. The summary provides an overview of the key courses and topics covered in the semester without including unnecessary details.
Today, communications is the largest sector of the electronics field. In addition, wireless, networking or other communications technologies are now contained in almost every electronic product. This makes a knowledge and understanding of communication a must rather than an option for every student. Without at least one course in communications, the student may graduate with an incomplete view of the products and systems so common today.
This document provides an overview of the Communication Engineering course EC6651. The objectives are to introduce various analog and digital communication methods, source and line coding techniques, and multiple access techniques used in communication systems. The 5 units cover topics like analog communication systems, digital communication, source and line codes/error control, multiple access techniques, and satellite/optical fiber/powerline communications. The course aims to help students understand and analyze linear and digital electronic circuits as applied to communication systems.
The document provides information about the analog communications subject for an engineering college. It includes the course objectives, outcomes, syllabus, textbooks, and lesson plan. The objectives are to analyze analog communication systems and understand various analog modulation techniques. The syllabus covers topics like linear modulation schemes, angle modulation schemes, transmitters and receivers, and noise sources and performance analysis. The lesson plan outlines five units to be covered in the course along with the relevant outcomes and references.
This document provides information about an Analog Communications course taught at Matrusri Engineering College. It includes the course objectives, outcomes, syllabus, textbooks, and lesson plan. The course objectives are to analyze analog communication systems and understand various analog modulation techniques. The syllabus covers topics like linear modulation schemes, angle modulation schemes, transmitters and receivers, and noise sources and types. The lesson plan outlines how the course will be taught over several units, focusing on the relevant course outcomes and textbooks.
Electronics and Communication Engineering : Communications, THE GATE ACADEMYklirantga
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This document describes the process of frequency modulation and demodulation through MATLAB simulation. It involves 5 tasks:
1) Modulation using a single tone modulating signal and analysis of the modulated signal spectrum.
2) Repeating task 1 using a multi-tone modulating signal.
3) Demodulation of the modulated signal using synchronous detection.
4) Repeating tasks 1-3 using a different multi-tone modulating signal.
5) Repeating tasks 1-3 using real speech signals as the modulating signal.
The MATLAB code generates the modulated signal, plots the modulating signal, carrier signal and modulated signal spectra. It also calculates the modulation index and modulated signal power for different modulation conditions
COMPARISON OF BER AND NUMBER OF ERRORS WITH DIFFERENT MODULATION TECHNIQUES I...Sukhvinder Singh Malik
This paper provides analysis of BER and Number of Errors for MIMO-OFDM wireless communication system by using different modulation techniques. Wireless designers constantly seek to improve the spectrum efficiency/capacity, coverage of wireless networks, and link reliability. So the performances of the wireless communication systems can be enhanced by using multiple transmit and receive antennas, which is generally referred to as the MIMO technique. Here analysis will be carried out for an OFDM wireless communication system using different modulation techniques and considering the effect and the wireless channel like AWGN, fading. Performance results will be evaluated numerically and graphically using the plots of BER versus SNR and plots of number of errors versus SNR.
This document discusses linear modulation techniques. It begins by defining modulation as the systematic alteration of a carrier waveform according to the characteristics of a message signal. The three parameters of a sinusoidal carrier that can be varied are amplitude, phase, and frequency.
It then describes the need for modulation, including making signals suitable for wireless transmission by shifting the spectrum into frequency bands where propagation is possible. Modulation also allows multiplexing of multiple messages and frequency assignment of different stations. Certain modulation techniques can improve the signal-to-noise ratio.
The document goes on to describe the specific modulation technique of double sideband suppressed carrier (DSB-SC) modulation in detail, including its implementation, spectrum, and coherent demodulation.
Channel characterization and modulation schemes of ultra wideband systemsijmnct
Channel measurements are generally the basis for channel models. Strictly speaking, channel models do
not exclusively require measurements, but it is a fact that all standardized models are derived from
measurements. This licentiate paper is focused on the characterization of ultra-wideband wireless channels.
The paper presents the characterization of ultra wide band system with their benefits and drawbacks within
the telecommunication industry. Furthermore with the advantages of Ultra wideband several modulation
techniques for UWB are discussed in this paper.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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Assessment and Planning in Educational technology.pptxKavitha Krishnan
In an education system, it is understood that assessment is only for the students, but on the other hand, the Assessment of teachers is also an important aspect of the education system that ensures teachers are providing high-quality instruction to students. The assessment process can be used to provide feedback and support for professional development, to inform decisions about teacher retention or promotion, or to evaluate teacher effectiveness for accountability purposes.
Thinking of getting a dog? Be aware that breeds like Pit Bulls, Rottweilers, and German Shepherds can be loyal and dangerous. Proper training and socialization are crucial to preventing aggressive behaviors. Ensure safety by understanding their needs and always supervising interactions. Stay safe, and enjoy your furry friends!
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
The simplified electron and muon model, Oscillating Spacetime: The Foundation...RitikBhardwaj56
Discover the Simplified Electron and Muon Model: A New Wave-Based Approach to Understanding Particles delves into a groundbreaking theory that presents electrons and muons as rotating soliton waves within oscillating spacetime. Geared towards students, researchers, and science buffs, this book breaks down complex ideas into simple explanations. It covers topics such as electron waves, temporal dynamics, and the implications of this model on particle physics. With clear illustrations and easy-to-follow explanations, readers will gain a new outlook on the universe's fundamental nature.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
Chapter 4 - Islamic Financial Institutions in Malaysia.pptx
Unit- 1 Amplitude Modulation.ppt
1. MATRUSRI ENGINEERING COLLEGE
DEPARTMENT OF ELECTRONICS AND COMMUNICATION
ENGINEERING
SUBJECT NAME: ANALOG COMMUNICATIONS (PC501EC)
FACULTY NAME: Dr. M.NARESH
Insert Your Photo here
MATRUSRI
ENGINEERING COLLEGE
2. ANALOG COMMUNICATIONS
COURSE OBJECTIVES:
1. To Analyze the Analog communication system requirements
2.To understand the Generation and Detection of various analog modulation
techniques
3.To Analyze the noise performance of analog modulation techniques
4.To understand AM and FM Receivers.
5. To Understand the Pulse modulation techniques
COURSE OUTCOMES:
CO1: Describe basic concepts of linear and non-linear modulation and
demodulation schemes
CO2: Compare analog modulation schemes in terms of modulation index,
transmission bandwidth, TX power etc.
CO3: Explaining various aspects of sampling theorem to produce various
pulse modulation schemes
CO4: Appreciate the structures of various AM and FM transmitters and
receivers and understand design parameters.
CO5: Estimate electronic noise parameters on various analog modulation
schemes.
MATRUSRI
ENGINEERING COLLEGE
3. SYLLABUS
UNIT I- Linear Modulation schemes: Need for modulation,
Amplitude Modulation (AM). Double side band suppressed carrier
(DSB –SC)modulation ,Hilbert transform, properties of Hilbert
transform. Pre-envelop. Complex envelope representation of band
pass signals, In-phase and Quadrature component representation of
band pass signals. Low pass representation of band pass systems.
Single side band (SSB) modulation and Vestigial-sideband (VSB)
modulation. Modulation and demodulation of all the modulation
schemes, COSTAS loop.
UNIT II- Angle modulation schemes: Frequency Modulation (FM)
and Phase modulation (PM), Concept of instantaneous phase and
frequency. Types of FM modulation: Narrow band FM and wide
band FM. FM spectrum in terms of Bessel functions. Direct and
indirect (Armstrong's) methods of FM generation. Balanced
discriminator, Foster–Seeley discriminator ,Zero crossing detector
and Ratio detector for FM demodulation. Amplitude Limiter in FM.
MATRUSRI
ENGINEERING COLLEGE
4. UNIT IV- Analog pulse modulation schemes: Sampling of
continuous time signals. Sampling of low pass and band pass signals.
Types of sampling. Pulse Amplitude Modulation (PAM) generation
and demodulation. Pulse time modulation schemes: PWM and PPM
generation and detection. Time Division Multiplexing.
UNIT III- Transmitters and Receivers: Classification of
transmitters. High level and low level AM transmitters. FM
transmitters. Principle of operation of Tuned radio frequency (TRF)
and super heterodyne receivers. Selection of RF amplifier. Choice of
Intermediate frequency. Image frequency and its rejection ratio
Receiver characteristics: Sensitivity, Selectivity, Fidelity, Double
spotting, Automatic Gain Control.
MATRUSRI
ENGINEERING COLLEGE
UNIT V- Noise Sources and types: Atmospheric noise, Shot noise
and thermal noise. Noise temperature. Noise in two-port network:
noise figure, equivalent noise temperature and noise bandwidth.
Noise figure and equivalent noise temperature of cascade stages.
Narrow band noise representation. S/N ratio and Figure of merit
calculations in AM, DSB-SC, SSB and FM systems, Pre-Emphasis and
De-Emphasis
5. TEXT BOOKS /REFERENCES
TEXT BOOKS:
1. Simon Haykin, “Communication Systems,” 2/e, Wiley India, 2011.,
2. B.P. Lathi, Zhi Ding, “Modern Digital and Analog Communication
Systems”, 4/e, Oxford University Press, 2016
3. P. Ramakrishna Rao, “Analog Communication,” 1/e, TMH, 2011.
REFERENCES:
1.Taub, Schilling, “Principles of Communication Systems”, Tata
McGraw‐Hill, 4th Edition, 2013.
2. John G. Proakis, Masond, Salehi, “Fundamentals of Communication
Systems”, PEA, 1st Edition,2006
MATRUSRI
ENGINEERING COLLEGE
6. LESSON PLAN:
UNIT I- Linear Modulation schemes
MATRUSRI
ENGINEERING COLLEGE
S. No. Topic(S)
No.
of Hrs
Relevant
COs
Text Book/
Reference
Book
1. Linear Modulation schemes: Need for modulation 02 CO1 T1,T2,T3
2. conventional Amplitude Modulation (AM) 03 CO1,CO2 T1,T2,T3
3. Double side band suppressed carrier (DSB –SC)mod
ulation, COSTAS LOOP
02 CO1,CO2 T1,T2,T3
4. Hilbert transform, properties of Hilbert transform. 01 CO1 T1,T2,T3
5. Pre-envelop. Complex envelope representation of
band pass signals, In-phase and Quadrature
component representation of band pass signals
01 CO1 T1,T2,T3
6. Low pass representation of band pass systems 01 CO1 T1,T2,T3
7. Single side band (SSB) modulation 02 CO1,CO2 T1,T2,T3
8. Vestigial-sideband (VSB) modulation 02 CO1,CO2 T1,T2,T3
TOTAL 14
7. PRE-REQUISITES FOR THIS COURSE:
PTSP III-SEM 3-Credits
ES215EC :SS IV-SEM 3-Credits
EXTERNAL SOURCES FOR ADDITIONAL LEARNING:
MATRUSRI
ENGINEERING COLLEGE
Description Proposed Actions
Relevance
With POs
Relevance
With PSOs
Modulation &
Demodulation of all
Techniques including
multiplexing .
Communication Lab PO3, PO4,
PO5
PSO2
CONTENT BEYOND SYLLABUS:
S. No. Topic Relevance with POs and
PSOs
1. Advanced Communication system PSO1
8. INTRODUCTION:
Introduced to communication system, need for modulation, modulation types,
frequency division multiplexing, single tone modulation, power relations in AM waves
& generation and detection of AM waves. Students will learn about double side band
suppressed carrier modulators, time domain and frequency domain description,
generation of DSBSC waves, balanced modulators, ring modulator, coherent detection of
DSB-SC modulated waves, COSTAS loop.
UNIT I- Linear Modulation schemes
OUTCOMES:
1.Discuss about the basic elements of communication system, importance of
modulation and different types of modulation..
2. Understand the time domain, frequency domain Description and power relations of
amplitude Modulation, various techniques of generation and Detection of AM.
3. Analyze the time domain, frequency domain description of Double Side Band
Suppressed Carrier (DSB SC), various generation techniques and detection techniques
of DSB SC.
MATRUSRI
ENGINEERING COLLEGE
9. Contents: Introduction
1.1 Need for modulation,
1.2 Amplitude modulation (AM).
1.3 Double side band suppressed carrier (DSB –sc)modulation ,
1.4 Hilbert transform, properties of Hilbert transform.
1.5 Pre-envelop, Complex envelope representation of band pass signals,
In-phase and quadrature component representation of band pass signals.
1.6 Low pass representation of band pass systems.
1.7 Single side band (SSB) modulation and
1.8 Vestigial-sideband (VSB) modulation.
OUTCOMES:
1.Discuss about the basic elements of communication system, importance of modulation and
different types of modulation..
2. Understand the time domain, frequency domain Description and power relations of
amplitude Modulation, various techniques of generation and Detection of AM.
3. Analyze the time domain, frequency domain description of Double Side Band Suppressed
Carrier (DSB SC), various generation techniques and detection techniques of DSB SC,
UNIT I- Linear Modulation schemes
MATRUSRI
ENGINEERING COLLEGE
10. CONTENTS:
Introduction
1.1 Need for modulation
OUTCOMES:
Discuss about the basic elements of communication system, importance of modulation
and different types of modulation.
MODULE-I
MATRUSRI
ENGINEERING COLLEGE
11. Communication is a process of conveying message at a distance.
If the distance is involved is beyond the direct communication, the communication
engineering comes into the picture. The brain engineering which deals with
communication systems is known as telecommunication engineering.
Telecommunication engineering is classified into two types based on transmission
media. They are:
1. Line communication
2. Radio communication
INTRODUCTION TO COMMUNICATION SYSTEM
MATRUSRI
ENGINEERING COLLEGE
The transmission of information from source to the destination through a channel or
medium is called communication
12. BASIC COMMUNICATION BLOCK DIAGRAM:
INTRODUCTION TO COMMUNICATION SYSTEM
MATRUSRI
ENGINEERING COLLEGE
Source: analog or digital
Transmitter: transducer, amplifier, modulator,oscillator, power amp., Antenna
Channel: Like Cable, optical fiber, freespace
Receiver: antenna, amplifier, demodulator, oscillator, power amplifier, Transducer
Destination : Like Person, (loud) speaker,computer
13. 1.1 Need for modulation
Modulation is the process of changing the characteristics parameters
(amplitude, frequency, phase) of the carrier signal, in accordance with the
instantaneous values of the modulating signal.
Need for Modulation: Baseband signals are incompatible for direct
transmission. For such a signal, to travel longer distances, its strength has to
be increased by modulating with a high frequency carrier wave, which
doesn’t affect the parameters of the modulating signal.
MATRUSRI
ENGINEERING COLLEGE
14. 1.1 NEED FOR MODULATION
1. Reduce the antenna height.
2. Increases the range of Communication.
3. Allows the multiplexing of signals.
4. Adjustments in the bandwidth is allowed.
5. Avoids the mixing of signals.
6. Improved reception quality
7. Narrow banding of signals.
MATRUSRI
ENGINEERING COLLEGE
Need for modulation:
15. 1.1 NEED FOR MODULATION
Message or Modulating Signal:
The signal which contains a message to be transmitted is called as a message signal.
It is a baseband signal, which has to undergo the process of modulation, to get
transmitted. Hence, it is also called as the modulating signal.
Carrier Signal :
The high frequency signal, which has a certain amplitude, frequency and phase but
contains no information, is called as a carrier signal. It is an empty signal and is used
to carry the signal to the receiver after modulation.
Modulated Signal:
The resultant signal after the process of modulation is called as a modulated signal.
This signal is a combination of modulating signal and carrier signal.
MATRUSRI
ENGINEERING COLLEGE
17. CONTENTS:
1.2 conventional amplitude modulation (AM).
OUTCOMES:
Understand the time domain, frequency domain Description and power relations of
Amplitude Modulation
MODULE-2
MATRUSRI
ENGINEERING COLLEGE
18. Amplitude Modulation:
The amplitude of the carrier signal varies in accordance with the
instantaneous amplitude of the modulating signal is called amplitude modulation .
1.2 AMPLITUDE MODULATION (AM)
MATRUSRI
ENGINEERING COLLEGE
19. 1.2 AMPLITUDE MODULATION (AM)
MATRUSRI
ENGINEERING COLLEGE
Time-domain Representation of the Waves:
Let the modulating signal be, m(t) = Am cos(2πfmt) eq., 1
and the carrier signal be, c(t)= Ac cos(2πfct) eq.,2
Where,
Am and Ac are the amplitude of the modulating signal and the carrier signal
respectively.
fm and fc are the frequency of the modulating signal and the carrier signal
respectively.
For our convenience, assume the phase angle of the carrier signal is zero. An amplitude-
modulated (AM) wave S(t) can be described as function of time is given by
S (t) = Ac [1+ka m (t)] cos2πfct eq.,3
Where ka = Amplitude sensitivity of the modulator
20. The equation 3, can be written as
S (t) = Ac cos2πfct + Ac ka m (t) cos2πfct eq., 4
The carrier wave, after being modulated, if the modulated level is calculated, then it is
called as Modulation Index or Modulation Depth .
SAM (t) = Ac [1+ka Am cos(2πfmt)] cos2πfct eq., 5
SAM (t) = Ac [1+µcos(2πfmt)] cos2πfct eq.,6
Where µ is “Modulation Index” or “Depth of Modulation”
1.2 AMPLITUDE MODULATION (AM)
MATRUSRI
ENGINEERING COLLEGE
c
m
A
A
2
/
2
/
min
max
min
max
A
A
A
A
A
A
c
m
m
in
m
ax
m
in
m
ax
A
A
A
A
then
eq.,7
eq.,8
eq.,9
21. 1.2 AMPLITUDE MODULATION (AM)
MATRUSRI
ENGINEERING COLLEGE
Frequency Domain Representation:
Frequency Spectrum of Modulating signal
Frequency Spectrum of Modulated signal
22. Bandwidth of Amplitude Modulation:
It is defined as the difference between the higher Upper side band frequency and Lower side band
frequency.
Band width (BW)= fUSB-fLSB = fc+fm- (fc-fm)=2fm
= 2 X Message Bandwidth/highest frequency
message signal
1.2 AMPLITUDE MODULATION (AM)
MATRUSRI
ENGINEERING COLLEGE
eq.,10
23. CONTENTS:
1.2. Amplitude Modulation
-Single Tone Modulation
-Multi tone Modulation
- Power and Efficiency calculation of AM
OUTCOMES:
Explain different types of AM modulation techniques and calculating power & Efficiency
MODULE-3
MATRUSRI
ENGINEERING COLLEGE
24. Single Tone Modulation:
Single tone modulation is “a modulation in which the modulation is carried out by a single frequency
(tone) signal”.
The toned (single frequency) modulating signal consists of only one frequency component and this
signal is modulated with a carrier signal.
Amplitude modulates signal SAM (t) = Ac [1+ka m (t)] cos2πfct
Let us consider single modulating signal m(t) = Am cos(2πfmt)
S (t) = Ac Cos (2π fct)+Acµ /2[cos2 π(fc+fm)t]+ Acµ /2[cos2π (fc-fm)t]
Fourier transform of S (t) is :
S (f) =Ac/2[𝝳 (f-fc) + (f+fc)] +Acµ /4[𝝳 (f-fc-fm) +𝝳 (f+fc+fm)]
+ Acµ /4[𝝳 (f- fc+fm ) +𝝳 (f+fc-fm)]
1.2 AMPLITUDE MODULATION (AM)
MATRUSRI
ENGINEERING COLLEGE
eq.,11
eq.,12
26. Multi Tone Modulation:
In multi-tone modulation modulating signal consists of more than one frequency component where
as in single-tone modulation modulating signal consists of only one frequency component .
Amplitude modulates signal SAM (t) = Ac [1+ka m (t)] cos2πfct
Let us consider single modulating signal m(t) = Am1cos(2πfm1t)+ Am2cos(2πfm2t)+-----
S (t) = Ac Cos (2π fct)+Acµ1 /2[cos2 π(fc+fm1)t]+ Acµ1 /2[cos2π (fc-fm1)t]
+Acµ2 /2[cos2 π(fc+fm2t]+ Acµ1 /2[cos2π (fc-fm2)t]+------
Fourier transform of S (t) is :
S (f) =Ac/2[𝝳 (f-fc) + (f+fc)] +Acµ1 /4[𝝳 (f-fc-fm1) +𝝳 (f+fc+fm1)]
+ Acµ1 /4[𝝳 (f- fc+fm1 ) +𝝳 (f+fc-fm1)]
+ Acµ2 /4[𝝳 (f-fc-fm2) +𝝳 (f+fc+fm2)]
+ Acµ2 /4[𝝳 (f- fc+fm2 ) +𝝳 (f+fc-fm2)]+----------
1.2 AMPLITUDE MODULATION (AM)
MATRUSRI
ENGINEERING COLLEGE
eq.,13
eq.,14
eq.,15
28. 1.2 AMPLITUDE MODULATION (AM)
MATRUSRI
ENGINEERING COLLEGE
Power Calculation of AM
Single - tone Modulation
Let the modulating signal be, m(t) = Am cos(2πfmt)
and the carrier signal be, c(t)= Ac cos(2πfct)
Then AM equation is S (t) = Ac [1+ka m (t)] cos2πfct
S (t) = Ac Cos (2π fct)+Acµ /2[cos2 π(fc+fm)t]+ Acµ /2[cos2π (fc-fm)t]
Total Power: Pt= Pc + PUSB+PLSB
Power of any signal is equal to the mean square value of the signal
Carrier power Pc = Ac2/2
Upper Side Band power PUSB = Ac2 µ2/8
Lower Side Band power P LSB = Ac2 µ2/8
Total power Pt = Pc + PLSB + PUSB
Total power Pt = Ac2/2 + Ac2 µ2/8 + Ac2 µ2/8
= Ac2/2 + Ac2 µ2/4
= Ac2/2[1 + µ2/2]
29. 1.2 AMPLITUDE MODULATION (AM)
MATRUSRI
ENGINEERING COLLEGE
Power Calculation of AM
Total power Pt = Ac2/2 + Ac2 µ2/8 + Ac2 µ2/8
= Ac2/2 + Ac2 µ2/4
= Ac2/2[1 + µ2/2]
Total power Pt =
Total power Pt =
2
2
2
1
2
c
A
2
2
1
c
P
1
2
1
2
1
2
2
c
t
C
T
c
t
I
I
V
V
P
P
30. 1.2 AMPLITUDE MODULATION (AM)
MATRUSRI
ENGINEERING COLLEGE
Transient Efficiency of AM(ղ)
It is defined as the ratio of power carried by the side bands to the total power available
t
LSB
USB
t
SB
P
P
P
P
P
2
1
2
4
2
2
2
2
2
C
C
A
A
2
/
1
2
/
2
2
100
2
/
1
2
/
2
2
X
31. 1.2 AMPLITUDE MODULATION (AM)
MATRUSRI
ENGINEERING COLLEGE
Power Calculation of AM
Multi-tone Modulation:
Total Power: Pt= Pc + PUSB1+PLSB1 + PUSB2+PLSB2+-------------------
Total power Pt = Ac2/2 + Ac2 µ12/8 + Ac2 µ12/8 + Ac2 µ22/8 + Ac2 µ22/8+--------
= Ac2/2 + Ac2 µ12/4 + Ac2 µ22/4+---------
= Ac2/2[1 + µ12/2+ µ22/2+-----]
= Ac2/2[1 + µt2/2]
Total power Pt = Pc[1 + µt2/2]
33. CONTENTS:
1.2. Generation and Detection of AM waves
A. Generation Methods
OUTCOMES:
, Discuss various techniques of generation AM.
MODULE-4
MATRUSRI
ENGINEERING COLLEGE
34. A. GENERATION OF AM WAVES:
1. Square –Law Modulator
2. Switching Modulator
B. DETECTION OF AM WAVES :
1. Synchronous detector
2. Square law detector
3. Rectifier detector
1.2 Generation and Detection of AM Waves
MATRUSRI
ENGINEERING COLLEGE
35. 1. Square –Law Modulator(1/3):
1.2 (a) Generation of AM Waves
MATRUSRI
ENGINEERING COLLEGE
Square –Law Modulator
36. Square –Law Modulator(2/3):
MATRUSRI
ENGINEERING COLLEGE
1.2 (a) Generation of AM Waves
)
(
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37. Square –Law Modulator(3/3):
Applying Fourier transform:
MATRUSRI
ENGINEERING COLLEGE
1.2 (a) Generation of AM Waves
After Passing through a BPF with the cutoff frequency fc
t
f
t
m
a
b
aA
t
bm
a
t
f
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38. 2. Switching Modulator :
1.2 (a) Generation of AM Waves
MATRUSRI
ENGINEERING COLLEGE
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cos
)
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2 t
m
t
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(
)
( 2
1
t
V
t
V C(t) > 0
C(t) <0
)
(
).
(
)
( 1
2 t
g
t
V
t
V p
Mathematically
With period To=1/fc and a duty cycle of 50%
)]
2
2
(
2
cos[
1
2
1
2
2
1
)
(
1
1
n
t
f
n
t
g c
n
n
p
39. 2. Switching Modulator :
1.2 (a) Generation of AM Waves
MATRUSRI
ENGINEERING COLLEGE
cs
oddHarmoni
t
f
t
g c
p
2
cos
2
2
1
)
(
]
2
cos
2
2
1
)][
(
2
cos
[
)
( cs
oddHarmoni
t
f
t
m
t
f
A
t
g c
c
c
p
cs
oddHarmoni
f
A
A
t
f
A
t
f
t
m
t
m
t
V
c
c
c
c
c
c
4
cos
2
cos
2
2
cos
)
(
2
2
)
(
)
(
2
t
f
A
t
f
t
m
t
V c
c
c
2
cos
2
2
cos
)
(
2
)
(
2
)]
(
1
[
2
cos
2
t
m
A
a
t
f
A
c
c
c
After Passing through a BPF
40. CONTENTS:
1.2. Detection Methods of AM
OUTCOMES:
Discuss various techniques of Detection of AM
MODULE-5
MATRUSRI
ENGINEERING COLLEGE
41. 1. Synchronous/Coherent Detector(1/2):
1.2 (b) Detection of AM Waves
MATRUSRI
ENGINEERING COLLEGE
t
f
A
t
f
t
m
k
A
t
S c
c
c
a
c
AM
2
cos
.
2
cos
)]
(
1
[
)
(
t
f
t
m
k
A
t
m
k
A
t
f
A
A
t
S c
a
c
a
c
c
c
c
AM )
2
(
2
cos
)
(
2
)
(
2
)
2
(
2
cos
2
2
)
(
2
2
2
2
)
(
2
)
(
2
t
m
k
A
t
S a
c
AM After Passing through LPF
42. 1. Synchronous/Coherent Detector(2/2):
1.2 (b) Detection of AM Waves
MATRUSRI
ENGINEERING COLLEGE
t
f
A
t
f
t
m
k
A
t
S c
c
c
a
c
AM )
2
cos(
.
2
cos
)]
(
1
[
)
(
t
t
f
t
t
f
A
t
f
t
m
k
A
A
t
S c
c
c
c
a
c
c
AM )
sin(
.
2
sin
cos
)
2
[cos(
.
2
cos
)]
(
[
)
(
For a phase ø:
When there is no proper synchronization ,then
cos
).
(
2
)
(
2
t
m
k
A
t
V a
c
o
)
(
2
)
(
2
t
m
k
A
t
V a
c
o
then
o
If ,
0
0
;
,
90 0
0
V
then
If
i.e., There is no De-Modulated output. This effect is called “ Quadrature -Null effect” .
In order to avoid above problem, we will maintain synchronization at receiver , but the
complexity of receiver will increase.
43. 2.SQUARE-LAW DETECTOR(1/2) :
1.2 (b) Detection of AM Waves
MATRUSRI
ENGINEERING COLLEGE
)
(
)
(
)
( 2
1
1
2 t
bV
t
aV
t
V
]
2
cos
)
(
1
(
[
]
2
cos
)
(
1
(
[
)
(
2
cos
)]
(
1
[
)
(
2
2
2
2
1
t
f
t
m
k
A
b
t
f
t
m
k
A
a
t
V
t
f
t
m
k
A
t
V
c
a
c
c
a
c
c
a
c
]
2
/
)
2
(
2
cos
1
)]
(
2
)
(
1
(
[
2
cos
)
(
2
cos
)
( 2
2
2
2 t
f
t
m
k
t
m
k
A
b
t
f
t
m
k
aA
t
f
aA
t
V c
a
a
c
c
a
c
c
c
]
)
2
(
2
cos
1
)][
(
2
2
)
(
2
2
[
2
cos
)
(
2
cos
2
2
2
2
2
2
2
t
f
t
m
k
A
b
t
m
k
bA
bA
t
f
t
m
k
aA
t
f
aA
c
a
c
a
c
c
c
a
c
c
c
44. 2.SQUARE-LAW DETECTOR(2/2) :
After passing through the LPF:
1.2 (b) Detection of AM Waves
MATRUSRI
ENGINEERING COLLEGE
)
(
)
(
2
2
)
(
]
)
2
(
2
cos
)]
(
)
(
2
2
[
)]
(
)
(
2
2
[
2
cos
)
(
2
cos
)
(
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
t
m
k
bA
t
m
k
bA
bA
t
y
t
f
t
m
k
bA
t
m
k
bA
bA
t
m
k
bA
t
m
k
bA
bA
t
f
t
m
k
aA
t
f
aA
t
V
a
c
a
c
c
c
a
c
a
c
c
a
c
a
c
c
c
a
c
c
c
)
(
)
(
2
)
( 2
2
2
2
2
t
m
k
bA
t
m
k
bA
t
V a
c
a
c
o
The unwanted terms gives rise to signal
distortion . The ratio to the desired signal
to undesired signal
)
(
2
)
(
2
)
(
2
2
2
2
t
m
k
t
m
k
bA
t
m
k
bA
N
S
a
a
c
a
c
45. 3. Envelope detector(1/2) :
1.2 (b) Detection of AM Waves
MATRUSRI
ENGINEERING COLLEGE
Half wave rectifier ,the Negative Portion is cliff off
Envelope detector
46. MATRUSRI
ENGINEERING COLLEGE
1.2 (b) Detection of AM Waves
c
s
f
c
R
1
c
L
f
c
R
1
m
L
f
c
R
1
The charging time constant RsC is very small when compared to the
carrier period 1/fc i.e.,
The Dis-charging time constant RsC is must large enough to
ensure that the capacitor discharges slowly through load capacitor
The discharging time constant should not exceed the period of
The message signal
47. 1.2 (b) Detection of AM Waves
MATRUSRI
ENGINEERING COLLEGE
mb
L
c
s
f
C
R
f
c
R
1
1
The discharging time constant RLC is very large when compared to the charging time
constant i.e.,
49. Condition to Avoid Diagonal Clipping:
1.2 (b) Detection of AM Waves
MATRUSRI
ENGINEERING COLLEGE
m
L C
R
2
1
The Max. time constant depends up on given modulation index and highest
frequency message signal without causing diagonal clipping.
0
)
(
dt
dE
t
V
dt
d
c
t
f
A
E m
c
2
cos
1
m
m
c
L
t
A
C
R
E
Thus
.
sin 0
50. CONTENTS:
1.3 double side band suppressed carrier (DSB –sc)modulation
.OUTCOMES:
Analyze the time domain, frequency domain description of Double Side Band
Suppressed Carrier (DSB SC)
MODULE-6
MATRUSRI
ENGINEERING COLLEGE
51. DSB-SC can be generated by using a Product modulator/Balanced Modulator with
message signal and Carrier signal getting multiplied.
1.3 Double side band suppressed carrier (DSB –sc)modulation
MATRUSRI
ENGINEERING COLLEGE
)
(
.
2
cos
)
( t
m
t
f
k
A
t
S c
a
c
52. Single-Tone Modulation
DSB-SC Modulated signal is: S (t) = Ac ka cos2πfct. m (t)
For a single tone ,
m(t)= Am cos2πfmt
Then, S (t) = Ac ka cos2πfct. Am cos2πfmt
= Ac Am/2[cos2π(fc + fm)t +cos2π(fc - fm)t ]
Fourier transform of S (t) is :
S (f) =AcAm /4[𝝳 (f-fc-fm) +𝝳 (f+fc+fm)] + AcAm /4[𝝳 (f- fc+fm ) +𝝳 (f+fc-fm)]
1.3 Double side band suppressed carrier (DSB –sc)modulation
MATRUSRI
ENGINEERING COLLEGE
53. 1.3 Double side band suppressed carrier (DSB –sc)modulation
MATRUSRI
ENGINEERING COLLEGE
54. 1.3 DOUBLE SIDE BAND SUPPRESSED CARRIER (DSB –SC)MODULATION
MATRUSRI
ENGINEERING COLLEGE
Power Calculation of DSB-SC
Let the modulating signal be, m(t) = Am cos (2πfmt)
and the carrier signal be, c(t)= Ac cos (2πfct)
Then DSB-SC equation is S (t) = Ac ka cos2πfct. m (t)
S (t) = Ac Am/2[cos2π(fc + fm)t +cos2π(fc - fm)t ]
Total Power: Pt= PUSB+PLSB
Total power Pt = Ac2 µ2/8 + Ac2 µ2/8
= Ac2 µ2/4
= Pc . µ2/2
Efficiency:
t
LSB
USB
t
SB
P
P
P
P
P
Efficiency is 100%
55. CONTENTS:
1.3. Generation and detection of DSB-SC waves
a. Generation methods
OUTCOMES:
Explain various generation techniques of DSB SC
MODULE-7
MATRUSRI
ENGINEERING COLLEGE
56. A. GENERATION OF AM WAVES:
1. Balanced Modulator
(a). Balanced Modulator using FET
(b). Balanced Modulator using BJT
2. Ring Modulator
B. DETECTION OF AM WAVES :
1. Synchronous detector
1.3. Generation and Detection of DSB-SC Waves
MATRUSRI
ENGINEERING COLLEGE
57. 1. Balanced modulator:
Carrier signal applied to two AM Modulators is same but the message signal modulating
wave is applied to one of the AM Modulator with the 180 degrees phase shift
1.3.(A)Generation of DSB-SC Waves
MATRUSRI
ENGINEERING COLLEGE
Balanced modulator
58. 1.3.(A) Generation of DSB-SC Waves
.
MATRUSRI
ENGINEERING COLLEGE
t
f
t
m
k
A
t
x c
a
c
2
cos
)]
(
1
[
)
(
1
The output of First AM generator is
The output of Second AM generator is t
f
t
m
k
A
t
x c
a
c
2
cos
)]
(
1
[
)
(
2
The output of Summer is: x1-x2:
t
f
t
m
k
A
t
f
t
m
k
A
t
y c
a
c
c
a
c
2
cos
)]
(
1
[
2
cos
)]
(
1
[
)
(
2
1
2
2
1
2
1 4
2 V
V
a
V
a
id
id
i
C
c
a A
t
f
t
m
k
t
y .
2
cos
).
(
2
)
(
59. 1(a).Balanced Modulator Using FET(Non-Linear Device):
In FET V1 is applied together in phase where as V2 appears 180 degrees out of phase to
one of the FETs since they are at opposite ends of the center tapped transformer
1.3 (a) Generation of DSB-SC Waves
MATRUSRI
ENGINEERING COLLEGE
Balanced Modulator Using FET
60. 1(a).Balanced Modulator Using FET(Non-Linear Device):
The currents output of push-pull center taped transformer id1:
1.3 (a) Generation of DSB-SC Waves
MATRUSRI
ENGINEERING COLLEGE
2
2
1
2
2
1
1
0
1 )
(
)
( V
V
a
V
V
a
a
id
2
2
1
2
2
1
1
0
2 )
(
)
( V
V
a
V
V
a
a
id
Then the output is:
2
1
2
2
1
2
1 4
2 V
V
a
V
a
id
id
i
If the output tank circuit tuned to a center frequency fc, then V0α I
)
(
2
cos
]
4
[
2
1
2
1
2
0
t
m
V
t
f
A
V
V
V
a
k
kI
V
c
c
ka
wherek
t
f
t
m
A
k
t
m
t
f
A
a
k
V
c
c
c
c
4
2
cos
).
(
.
.
)]
(
.
2
cos
.
4
[
1
1
2
0
Then
61. 1(b).Balanced Modulator Using BJT (Non-Linear Device):
1.3 (a) Generation of DSB-SC Waves
MATRUSRI
ENGINEERING COLLEGE
Balanced Modulator Using BJT
62. 1.3 (a) Generation of DSB-SC Waves
MATRUSRI
ENGINEERING COLLEGE
2. Ring Modulator(1/2):
Mathematically the square wave is represented as:
]
)
1
2
(
2
cos[
1
2
)
1
(
4
)
( 1
1
t
n
f
n
t
c c
n
n
.....]
)
3
(
2
cos
3
1
2
[cos
4
)
(
t
f
t
f
t
c c
c
63. 2. RING MODULATOR(2/2):
The output of the Ring Modulator is :
When s(t) is passed through a BPF, Then the o/p of the filter is:
1.3 (a) Generation of DSB-SC Waves
MATRUSRI
ENGINEERING COLLEGE
.....)]
)
3
(
2
cos
).
(
3
1
2
cos
).
(
[
4
)
(
.....)]
)
3
(
2
cos
3
1
2
[cos
4
)(
(
)
(
)
(
).
(
)
(
t
f
t
m
t
f
t
m
t
s
t
f
t
f
t
m
t
s
t
c
t
m
t
s
c
c
c
c
t
f
t
m
t
s c
2
cos
).
(
4
)
(
65. CONTENTS:
1.3.B. Detection of DSB-SC wave
Detection Methods
OUTCOMES:
Explain various detection techniques of DSB SC
MODULE-8
MATRUSRI
ENGINEERING COLLEGE
66. 1.Coherent/Synchronous Detector:
MATRUSRI
ENGINEERING COLLEGE
1.3.(B) Detection of DSB-SC Waves
)
(
2
)
(
]
)
2
(
2
cos
1
)[
(
2
)
(
2
cos
).
(
)
(
2
cos
.
2
cos
).
(
)
(
)
(
2
cos
).
(
)
(
2
2
2
2
t
m
A
t
y
AfterLPF
t
f
t
m
A
t
y
t
f
t
m
A
t
y
t
f
A
t
f
t
m
A
t
y
AfterLPF
t
y
t
f
A
t
S
t
x
c
c
c
c
c
c
c
c
C
c
c
67. When there is NO Perfect Synchronization, two distortions arises:
1. Effect of Phase distortion
2. Effect of Frequency distortion
1.3(B) Detection of DSB-SC Waves
MATRUSRI
ENGINEERING COLLEGE
0
)
(
,
90
)
(
2
)
(
,
0
cos
)
(
2
)
(
]
cos
)
4
)[cos(
(
2
)
(
)
2
cos(
.
2
cos
)
(
)
(
)
2
cos(
).
(
)
(
0
2
0
2
2
t
y
t
m
A
t
y
when
t
t
m
A
t
y
AfterLPF
t
t
t
f
t
m
A
t
x
t
f
A
t
f
t
m
A
t
x
t
f
A
t
S
t
x
c
c
c
c
c
c
c
c
c
c
1. Effect of Phase distortion:
When there is phase shift of π/2, the demodulated output is zero, Even though the input is
present. This effect is called “Quadrature null effect”
68. 2.Effect of Frequency distortion
1.3(B) Detection of DSB-SC Waves
MATRUSRI
ENGINEERING COLLEGE
When there is frequency distortion, each signal undergo a shift of ⍙f and power reduced
By Factor 2. Phase distortion can be tolerated but nor frequency distortion
]
)
2
cos(
)
4
)[cos(
(
2
)
(
)
(
2
cos
.
2
cos
)
(
)
(
)
(
2
cos
).
(
)
(
2
t
f
t
f
f
t
m
A
t
x
f
f
A
t
f
t
m
A
t
x
t
f
f
A
t
S
t
x
c
c
c
c
c
c
c
c
)
2
(
4
2
2
4
)]
(
)
(
[
4
)
(
]
)
(
2
)[cos
(
2
)
(
:
4
4
1
2
2
edby
powerreduc
P
X
A
P
X
A
P
f
f
M
f
f
M
A
F
Y
t
f
t
m
A
t
y
AfterLPF
m
c
m
c
c
c
69. 2. COSTAS LOOP(1/2):
1.3 (B) Detection of DSB-SC Waves
MATRUSRI
ENGINEERING COLLEGE
Synchronization Techniques:
1. Use of Pilot Carrier
2. COSTAS LOOP
3. Squaring LOOP
70. 2. COSTAS LOOP(2/2):
1.3 (B) Detection of DSB-SC Waves
MATRUSRI
ENGINEERING COLLEGE
If ø error=0,
I-channel o/p: Ac2 /2 m(t)
Q-channel o/p:0
Then the o/p of I-Channel taken as Demodulated signal
When there is a small amount of Phase error, then:
I-channel o/p: Ac2 /2 m(t). Cos ø
Q-channel o/p: Ac2 /2 m(t).sin ø
Then Phase Discriminator output is:
Output is: Ac2 /2 m(t). ø
71. 3. Squaring LOOP:
Unlike COSTAS LOOP , the squaring LOOP extracts the carrier signal of correct
frequency and phase from the received DSB-SC Signal
1.3(B) Detection of DSB-SC Waves
MATRUSRI
ENGINEERING COLLEGE
Squaring LOOP
72. 3. Squaring LOOP:
The limiter output is:
1.3 (B) Detection of DSB-SC Waves
MATRUSRI
ENGINEERING COLLEGE
)
(
.
2
1
4
cos
).
(
2
2
1
)
(
]
4
cos
1
)[
(
2
)
(
)
(
.
2
cos
)
(
)
(
)
(
.
2
cos
.
)
(
2
2
2
2
2
t
m
A
t
f
t
m
A
t
z
t
f
t
m
A
t
y
t
m
t
f
A
t
x
t
y
t
m
t
f
A
t
x
c
c
c
c
c
c
c
c
c
t
f
K
t
w c
4
cos
.
)
( 1
The frequency divider output is:
t
f
K
t
f
K
t
V c
c
2
cos
.
2
4
cos
.
)
( 2
2
73. CONTENTS:
1.4 Hilbert transform, properties of hilbert transform
OUTCOMES:
Discuss about Hilbert transform and its properties
MODULE-9
MATRUSRI
ENGINEERING COLLEGE
74. Hilbert Transform: Hilbert transform is a method of separating w. r.t Phase contents
i.e., When all the phase angle of signal components are shifted by ± π/2 then the
resultant function is:
1. Fourier, Laplace, and z-transforms change from the time-domain representation of a
signal to the frequency-domain representation of the signal.
2. The resulting two signals are equivalent representations of the same signal in terms of
time or frequency.
3. In contrast, The Hilbert transform does not involve a change of domain, unlike many
other transforms .
4. First, the result of a Hilbert transform is not equivalent to the original signal, rather it
is a completely different signal.
5. Second, the Hilbert transform does not involve a domain change, i.e., the Hilbert
transform of a signal x(t) is another signal denoted by in the same domain
(i. e., time domain)
1.4 Hilbert transform, properties of Hilbert transform
MATRUSRI
ENGINEERING COLLEGE
)
(
ˆ t
x
75. The Hilbert transform of a signal x(t) is a signal whose frequency components lag
the frequency components of x(t) by 90.
has exactly the same frequency components present in x(t) with the same
amplitude–except there is a 90 phase delay.
The Hilbert transform of x(t) = Acos (2f0t + ) is Acos (2f0t + - 90) = Asin (2f0t + ).
1.4 Hilbert transform, properties of Hilbert transform
MATRUSRI
ENGINEERING COLLEGE
)
(
ˆ t
x
)
(
ˆ t
x
)
(
)
sgn(
)
(
ˆ f
X
f
j
t
x
F
t
f
j
F
1
)
sgn(
1
d
t
x
t
x
t
t
x
)
(
1
)
(
1
)
(
ˆ
The operation
of the Hilbert
transform is
equivalent to a
convolution, i.e.,
filtering
76. Properties of Hilbert Transform:
1. Evenness and Oddness:
The Hilbert transform of an even signal is odd, and the Hilbert transform of an odd
signal is even
1.4 Hilbert transform, properties of Hilbert transform
MATRUSRI
ENGINEERING COLLEGE
Proof
If x(t) is even, then X(f) is a real and even function
Therefore, -jsgn(f)X(f) is an imaginary and odd function
Hence, its inverse Fourier transform will be odd
If x(t) is odd, then X(f) is imaginary and odd
Thus -jsgn(f)X(f) is real and even
Therefore, is even
)
(
ˆ t
x
)
(
ˆ t
x
77. Properties of hilbert -transform:
2. Sign reversal:
Applying the hilbert-transform operation to a signal twice causes a sign reversal of the
signal, i.e
X( f ) does not contain any impulses at the origin
1.4 Hilbert transform, properties of Hilbert transform
MATRUSRI
ENGINEERING COLLEGE
)
(
)
(
ˆ
ˆ t
x
t
x
)
(
)
sgn(
)]
(
ˆ
ˆ
[
2
f
X
f
j
t
x
F
)
(
)]
(
ˆ
ˆ
[ f
X
t
x
F
Proof:
78. Properties of Hilbert Transform:
3.Energy
The energy content of a signal is equal to the energy content of its Hilbert
transform
1.4 Hilbert transform, properties of Hilbert transform
MATRUSRI
ENGINEERING COLLEGE
Proof
Using Rayleigh's theorem of the Fourier transform
df
f
X
dt
t
x
Ex
2
2
)
(
)
(
df
f
X
df
f
X
f
j
dt
t
x
Ex
2
2
2
ˆ )
(
)
(
)
sgn(
)
(
ˆ
Using the fact that |-jsgn(f)|2 = 1 except for f = 0, and the fact that X(f)
does not contain any impulses at the origin completes the proof
79. Properties of hilbert -transform:
4. Orthogonality
The signal x(t) and its hilbert transform are orthogonal
Using Parseval's theorem of the Fourier transform, we obtain
1.4 Hilbert transform, properties of Hilbert transform
MATRUSRI
ENGINEERING COLLEGE
Proof:
df
f
X
f
j
f
X
dt
t
x
t
x *
*
)]
(
)
sgn(
)[
(
)
(
ˆ
)
(
0
)
(
)
(
0
2
0 2
df
f
X
j
df
f
X
j
In the last step, we have used the fact that X(f) is Hermitian;
| X(f)|2 is even.
80. CONTENTS:
1.5. Pre-envelop, complex envelope representation of band pass signals in-phase and
quadrature components
OUTCOMES:
Analyze the concept of band pass signals representation
MODULE-9
MATRUSRI
ENGINEERING COLLEGE
81. Let x(t) is real valued signal, then complex signal representation is
1.5 .Pre-envelop, complex envelope representation of band pass signals
MATRUSRI
ENGINEERING COLLEGE
Let x(t) be a BP signal(it consists of non –zero freq. components, centered at fc
and BW=2w)
)
(
)
(
)
(
)
(
)
(
)
(
)
(
)
(
)
(
f
jx
f
x
f
x
simillarly
f
jx
f
x
f
x
afterFT
t
jx
t
x
t
x
sin
).
(
.
cos
).
(
]
sin
).[cos
(
).
(
)
(
:
~
t
m
j
t
m
j
t
m
e
t
m
t
x
Envelope
Natual
j
Pre-Envelope
82. 1.5 .Pre-envelop, complex envelope representation of band pass signals
MATRUSRI
ENGINEERING COLLEGE
.
))
(
2
(
).
(
)
(
]
(
sin
.
2
sin
)
(
cos
.
2
)[cos
(
)
(
2
sin
)
(
2
cos
).
(
)
(
:
))
(
2
cos(
).
(
)
(
t
fct
j
Q
I
e
t
m
t
x
then
t
fct
t
fct
t
m
t
x
fct
t
X
fct
t
x
t
x
envelope
pre
t
fct
t
m
t
Letx
)
(
2
))
(
2
(
2
~
).
(
.
).
(
).
(
)
( t
j
fct
j
t
fct
j
fct
j
e
t
m
e
e
t
m
e
t
x
t
x
Complex –Envelop:
)
(
)
(
~
t
m
t
x
Natural–Envelop:
In-phase and Quadrature component:
sin
).
(
.
cos
).
(
]
sin
).[cos
(
).
(
)
(
~
t
m
j
t
m
j
t
m
e
t
m
t
x j
83. CONTENTS:
1.6. Low pass representation of band pass systems
OUTCOMES:
Analyze the Low pass signal representation
MODULE-10
MATRUSRI
ENGINEERING COLLEGE
84. A linear time invariant band pass system is one which accepts an input signal x(t),
processes it in some manner, depending upon its impulse response function, h(t) and
gives a band pass signal y(t) as the output signal.
1.6. Low pass representation of band pass systems
MATRUSRI
ENGINEERING COLLEGE
d
h
t
x
t
h
t
x
t
y
s
LTISystemi
jugation
complexcon
is
e
t
y
e
t
y
t
h
e
t
y
t
y
and
e
t
h
e
t
h
t
h
e
t
h
t
h
e
t
x
e
t
x
t
x
e
t
x
t
x
t
f
j
t
f
j
t
f
j
t
f
j
t
f
j
t
f
j
t
f
j
t
f
j
t
f
j
c
c
c
c
c
c
c
c
c
)
(
)
(
)
(
*
)
(
)
(
:
*
]
)
(
)
(
[
2
1
)
(
]
)
(
Re[
)
(
]
)
(
)
(
[
2
1
)
(
]
)
(
Re[
)
(
]
)
(
)
(
[
2
1
)
(
]
)
(
Re[
)
(
2
~
*
2
~
2
~
2
~
*
2
~
2
~
2
~
*
2
~
2
~
85. 1.6. Low pass representation of band pass systems
MATRUSRI
ENGINEERING COLLEGE
:
d
e
h
e
t
x
e
h
e
t
x
d
h
e
t
x
h
e
t
x
t
y
d
e
h
e
h
e
t
x
e
t
x
t
y
t
iny
t
h
t
subx
t
f
j
t
f
j
t
f
j
t
f
j
t
f
j
t
f
j
t
f
j
t
f
j
t
f
j
t
f
j
c
c
c
c
c
c
c
c
c
c
}
)
(
)
(
).
(
)
(
{
4
1
)}
(
)
(
)
(
)
(
{
4
1
)
(
}
)
(
)
(
}{
)
(
)
(
{
4
1
)
(
)
(
)
(
&
)
(
)
(
4
~
)
(
2
*
~
)
(
4
~
*
)
(
2
~
*
~
)
(
2
*
~
~
)
(
2
~
)
(
2
*
~
)
(
2
~
)
(
2
*
~
)
(
2
~
]
).
(
Re[
)
(
]
).
(
).
(
[
2
1
)
(
)
(
)
(
2
1
)
(
]
}
)
(
)
(
4
1
)
(
)
(
4
1
)
(
2
~
2
~
*
2
~
~
~
~
2
*
~
~
~
~
t
f
j
t
f
j
t
f
j
t
f
j
c
c
c
c
e
t
y
t
y
e
t
y
e
t
y
t
y
d
h
t
x
t
y
Then
e
d
h
t
x
d
h
t
x
t
y
)]
(
*
)
(
[
2
1
)
(
)
(
2
1
)
(
~
~
~
~
~
h
t
x
d
h
t
x
t
y
86. CONTENTS:
1.7 Single side band (SSB) modulation
OUTCOMES:
Analyze the time domain, frequency domain description of Vestigle Side Band
Suppressed Carrier (VSB- SC)
MODULE-11
MATRUSRI
ENGINEERING COLLEGE
87. SSB-SC: It is a form Amplitude modulation in which the carrier is fully suppressed and
one of the side bands (LOWER/UPPER) also suppressed.
1.7 Single side band (SSB) modulation
MATRUSRI
ENGINEERING COLLEGE
88. Derivation for USB-SC:
1.7 Single side band (SSB) modulation
MATRUSRI
ENGINEERING COLLEGE
j
j
e
e
t
m
j
A
e
e
t
m
A
t
S
e
t
m
A
e
t
m
A
t
S
f
f
M
f
f
M
A
IFT
t
S
f
S
IFT
t
S
f
f
M
f
f
M
A
f
S
t
jw
t
jw
c
t
jw
t
jw
c
USB
t
jw
c
t
jw
c
USB
c
c
c
USB
USB
USB
c
c
c
USB
c
c
c
c
c
c
.
2
)
).(
(
2
2
)
).(
(
2
)
(
2
).
(
2
2
).
(
2
)
(
)]
(
)
(
(
2
[
)
(
)]
(
[
)
(
)]
(
)
(
[
2
)
(
t
t
m
A
t
t
m
A
t
S c
c
c
c
LSB
sin
).
(
2
cos
).
(
2
)
(
t
t
m
A
t
t
m
A
t
S c
c
c
c
USB
sin
).
(
2
cos
).
(
2
)
(
89. Derivation for LSB-SC:
1.7 Single side band (SSB) modulation
MATRUSRI
ENGINEERING COLLEGE
j
j
e
e
t
m
j
A
e
e
t
m
A
t
S
e
t
m
A
e
t
m
A
t
S
f
f
M
f
f
M
A
IFT
t
S
f
S
IFT
t
S
f
f
M
f
f
M
A
f
S
t
jw
t
jw
c
t
jw
t
jw
c
USB
t
jw
c
t
jw
c
USB
c
c
c
USB
LSB
LSB
c
c
c
LSB
c
c
c
c
c
c
.
2
)
).(
(
2
2
)
).(
(
2
)
(
2
).
(
2
2
).
(
2
)
(
)]
(
)
(
(
2
[
)
(
)]
(
[
)
(
)]
(
)
(
[
2
)
(
t
t
m
A
t
t
m
A
t
S c
c
c
c
LSB
sin
).
(
2
cos
).
(
2
)
(
90. CONTENTS:
1.7 Single side band (SSB) modulation
a. Generation
b. Detection
OUTCOMES:
Understand the different types of generation techniques and detection technique.
MODULE-11
MATRUSRI
ENGINEERING COLLEGE
91. (a)Generation of SSB-SC:
1.Filter method/Balanced modulator method
2. Phase discriminator method
3. Third method/Weaver’s Method
(b) Detection of SSB-SC:
1. Coherent/Synchronous Detector:
1.7 Single side band (SSB) modulation
MATRUSRI
ENGINEERING COLLEGE
Generation of SSB-SC
93. 2. Phase discriminator method:
1.7 (a) Generation of SSB-SC
MATRUSRI
ENGINEERING COLLEGE
Phase discriminator method
94. 1.7 (a) Generation of SSB-SC
3. Third method/Weaver’s Method:
MATRUSRI
ENGINEERING COLLEGE
95. 1Coherent/Synchronous Detector:
1.7 (b) Detection of SSB-SC
MATRUSRI
ENGINEERING COLLEGE
)
(
4
)
(
:
4
sin
).
(
4
4
cos
)
(
4
)
(
4
)
(
2
cos
].
2
sin
).
(
2
cos
).
(
[
2
)
(
2
cos
).
(
)
(
]
2
sin
).
(
2
cos
).
(
[
2
)
(
2
2
2
2
t
m
A
t
z
AfterLPF
t
f
t
m
A
t
f
t
m
A
t
m
A
t
y
t
f
A
t
f
t
m
t
f
t
m
A
t
y
t
f
A
t
s
t
y
t
f
t
m
t
f
t
m
A
t
S
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
c
sc
ssb
96. CONTENTS:
1.8 Vestigial-sideband (VSB) modulation
OUTCOMES:
Analyze the time domain, frequency domain description of Vestigle Side Band Suppressed Carrier
(VSB- SC), generation techniques and detection technique.
MODULE-12
MATRUSRI
ENGINEERING COLLEGE
97. Vestigial sideband modulation or VSB modulation is the procedure where a part of the
signal called as vestige is modulated, along with one sideband. A VSB signal can be
plotted as shown in the resulting figure.
1.8 Vestigial-sideband (VSB) modulation
MATRUSRI
ENGINEERING COLLEGE
98. Generation of VSB-SC:
1.8 .(a) Generation & Detection of VSB-SC
MATRUSRI
ENGINEERING COLLEGE
Detection of VSB-SC:
99. 1. 400hz, 600hz and 800hz three audio signals. AM modulates the carrier of 4000 khz
signal. What are the frequencies present in the output?
2. For a given AM signal s(t)=acos(10000t)+bcos(10800t)+acos(11600t). The carrier
power is 200W and the efficiency of transmission is 30%. Determine A, B and
modulation index.
3. An AM wave has peak to peak voltage of 600V and valley to valley voltage of 100V.
Find the percentage depth of modulation.
4. A 360W carrier is simultaneously amplitude modulated by two audio waves with
modulation percentages of 55% and 65% respectively. What is the total sideband
power radiated?
5. Calculate the net modulation index and power associated with AM signal given bys (t)
=8cos2π+4cos2π2π+2cos2π.
6. An AM signal is of form s(t)=10(1+0.5cos2000πt+0.5cos4000πt).Sketch the spectrum
and find average power , total power , side band power , power efficiency and
modulation index.
Assignment Questions
MATRUSRI
ENGINEERING COLLEGE
100. 7. A tuned circuit of the oscillator in an AM transmitter uses a 50µh coil and 1nf
capacitor. Now if the oscillator output is modulated by audio frequencies up to8 khz
then find the frequency range occupied by sidebands.
8. A transmitter radiates 9KW without modulation and 10.125KW after modulation.
Determine the depth of modulation.
9. The output power of an AM transmitter is 1KW when sinusodially modulated to a
depth of 100%. Calculate the power in each side band when the modulation depth is
reduced to 50%.
10. For an AM DSBFC wave with peak un-modulated carrier voltage vc =10vp, a load
resistance of =10Ω and a modulation co-efficient of 1. Determine power of carrier,
upper and lower sideband. Total power of modulated wave. Total sideband power.
Draw the power spectrum.
11. The antenna current of an AM transmitter is 8A if only the carrier is sent, but it
increases to 8.93A if the carrier is modulated by a single sinusoidal wave. Determine
the percentage modulation. Also find the antenna current if the percent of
modulation changes to 0.8.
Assignment Questions
MATRUSRI
ENGINEERING COLLEGE
101. Short answer questions
Questions & Answers
MATRUSRI
ENGINEERING COLLEGE
S.NO QUESTION
Blooms
Taxonomy
Level
Course
Outcome
1. Explain the need for modulation. L1 CO1
2. What is meant by quadrature null effect? L1 CO1
3. Define modulation. What are the different types of
modulations?
L1 CO1
4. Define complex and pre-envelopes of signal. L1 CO1
5. Why quadrature null effect is not serious in SSB as in DSB-
SC?
L1 CO1
6. Draw the block diagram of a general communication system. L1 CO1
7. Write advantages of SSB. L1 CO1
8. Define Hilbert transform and mention any three properties
of HT.
L1 CO1
102. Long answer questions
Questions & Answers
MATRUSRI
ENGINEERING COLLEGE
S.NO QUESTION
Blooms
Taxonomy
Level
Course
Outcome
1. With a neat diagram, explain the frequency components of
AM wave.
L2 CO1
2. Explain the working of RING MODULATOR for generation of
DSBSC wave.
L2 CO1
3. For an AM DSBFC wave with peak un-modulated carrier
voltage Vc=10Vp, a resistance RL=10ohm and a modulation
co-efficient m=1 determine: power of carrier, USB, LSB total
power of modulated wave, total side band power, draw the
power spectrum
L2
CO1
4. Explain Weavers method for generating an SSB signal with
the help of a neat block diagram
L2 CO1
5. Derive an Expression for the total transmitter power in the
AM wave. Also obtain its efficiency.
L2 CO1