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.
3.Frequency Domain Representation of Signals and SystemsINDIAN NAVY
This document provides an overview of frequency domain representation of signals and systems. It defines key concepts such as the Fourier transform, which converts a signal from the time domain to the frequency domain. The frequency spectrum shows the distribution of frequencies within a signal. Periodic signals can be represented using Fourier series, while aperiodic signals use the Fourier transform. Properties of the Fourier transform such as linearity, time shifting, and the convolution theorem are also covered.
This document provides an overview of noise in amplitude modulation systems. It discusses the noise calculation and signal-to-noise ratio for various AM systems, including double sideband suppressed carrier (DSB-SC), single sideband suppressed carrier (SSB-SC), and AM with envelope detection. It describes the components and operation of a basic AM receiver, including RF amplification, mixing, intermediate frequency filtering and amplification, and demodulation. It also explains the advantages of the superheterodyne receiver principle for gain, filtering, and multiplexing of different carrier frequencies.
1. The document discusses key concepts in quantum physics including Planck's quantum theory, de Broglie's hypothesis of matter waves, Heisenberg's uncertainty principle, and Schrodinger's time-independent wave equation.
2. It provides details on experiments that verified the wave-like properties of matter including electron diffraction experiments by Davisson and Germer.
3. The document derives expressions for the energy levels of particles confined in one-dimensional potential wells and boxes in terms of Planck's constant and other variables.
Erbium-Doped Fiber Amplifier (EDFA) is an optical amplifier used in the C-band and L-band, where the loss of telecom optical fibers becomes lowest in the entire optical telecommunication wavelength bands. Invented in 1987, an EDFA is now most commonly used to compensate the loss of an optical fiber in long-distance optical communication. Another important characteristic is that EDFA can amplify multiple optical signals simultaneously, and thus can be easily combined with WDM technology.
A Gunn diode is a type of diode that uses the Gunn effect to generate microwave frequencies when a voltage above a threshold is applied. It consists of a single piece of N-type semiconductor like gallium arsenide and has a negative differential resistance region in its current-voltage characteristics that allows it to function as an oscillator. Gunn diodes are used to generate microwave signals from 10 GHz to THz and have applications in radar, sensors, and microwave transmission.
This document provides information about the course "ANALOG COMMUNICATION" including the course code, instructor details, course contents which are divided into 5 units covering topics like introduction to communication systems, amplitude modulation, angle modulation, transmitters and receivers, and noise in analog communication. It lists the textbooks recommended for different units. One of the units is about noise in analog communication which is further divided into two parts - part 1 covering topics like introduction to noise, sources of noise (external and internal), classification of noise, thermal noise calculations, signal to noise ratio, noise figure and cascaded amplifiers etc.
Active noise cancellation uses a microphone to measure ambient noise and generate an inverted "anti-noise" signal to destructively interfere with and cancel out the noise. It works best for low frequencies while passive noise control using insulation is more effective at higher frequencies. Adaptive noise cancellation algorithms like LMS analyze noise waveforms and generate inverted signals through transducers to reduce perceived noise levels. Noise-cancelling headphones apply this technique to improve listening and sleep on planes by offsetting engine noise.
This document discusses cavity resonators and ultra-wideband (UWB) systems. It begins with an introduction to cavity resonators and mentions that they are useful microwave devices. It then discusses different types of cavity resonators, including rectangular and circular cavity resonators. The document also covers applications of cavity resonators and UWB systems. For UWB systems, it notes that they use very short sub-nanosecond pulses across a wide bandwidth and have features like unlicensed spectrum use, high data rates, and immunity to multipath fading. It also discusses UWB antennas and their requirements like operating across the entire frequency band simultaneously with minimal pulse distortion.
3.Frequency Domain Representation of Signals and SystemsINDIAN NAVY
This document provides an overview of frequency domain representation of signals and systems. It defines key concepts such as the Fourier transform, which converts a signal from the time domain to the frequency domain. The frequency spectrum shows the distribution of frequencies within a signal. Periodic signals can be represented using Fourier series, while aperiodic signals use the Fourier transform. Properties of the Fourier transform such as linearity, time shifting, and the convolution theorem are also covered.
This document provides an overview of noise in amplitude modulation systems. It discusses the noise calculation and signal-to-noise ratio for various AM systems, including double sideband suppressed carrier (DSB-SC), single sideband suppressed carrier (SSB-SC), and AM with envelope detection. It describes the components and operation of a basic AM receiver, including RF amplification, mixing, intermediate frequency filtering and amplification, and demodulation. It also explains the advantages of the superheterodyne receiver principle for gain, filtering, and multiplexing of different carrier frequencies.
1. The document discusses key concepts in quantum physics including Planck's quantum theory, de Broglie's hypothesis of matter waves, Heisenberg's uncertainty principle, and Schrodinger's time-independent wave equation.
2. It provides details on experiments that verified the wave-like properties of matter including electron diffraction experiments by Davisson and Germer.
3. The document derives expressions for the energy levels of particles confined in one-dimensional potential wells and boxes in terms of Planck's constant and other variables.
Erbium-Doped Fiber Amplifier (EDFA) is an optical amplifier used in the C-band and L-band, where the loss of telecom optical fibers becomes lowest in the entire optical telecommunication wavelength bands. Invented in 1987, an EDFA is now most commonly used to compensate the loss of an optical fiber in long-distance optical communication. Another important characteristic is that EDFA can amplify multiple optical signals simultaneously, and thus can be easily combined with WDM technology.
A Gunn diode is a type of diode that uses the Gunn effect to generate microwave frequencies when a voltage above a threshold is applied. It consists of a single piece of N-type semiconductor like gallium arsenide and has a negative differential resistance region in its current-voltage characteristics that allows it to function as an oscillator. Gunn diodes are used to generate microwave signals from 10 GHz to THz and have applications in radar, sensors, and microwave transmission.
This document provides information about the course "ANALOG COMMUNICATION" including the course code, instructor details, course contents which are divided into 5 units covering topics like introduction to communication systems, amplitude modulation, angle modulation, transmitters and receivers, and noise in analog communication. It lists the textbooks recommended for different units. One of the units is about noise in analog communication which is further divided into two parts - part 1 covering topics like introduction to noise, sources of noise (external and internal), classification of noise, thermal noise calculations, signal to noise ratio, noise figure and cascaded amplifiers etc.
Active noise cancellation uses a microphone to measure ambient noise and generate an inverted "anti-noise" signal to destructively interfere with and cancel out the noise. It works best for low frequencies while passive noise control using insulation is more effective at higher frequencies. Adaptive noise cancellation algorithms like LMS analyze noise waveforms and generate inverted signals through transducers to reduce perceived noise levels. Noise-cancelling headphones apply this technique to improve listening and sleep on planes by offsetting engine noise.
This document discusses cavity resonators and ultra-wideband (UWB) systems. It begins with an introduction to cavity resonators and mentions that they are useful microwave devices. It then discusses different types of cavity resonators, including rectangular and circular cavity resonators. The document also covers applications of cavity resonators and UWB systems. For UWB systems, it notes that they use very short sub-nanosecond pulses across a wide bandwidth and have features like unlicensed spectrum use, high data rates, and immunity to multipath fading. It also discusses UWB antennas and their requirements like operating across the entire frequency band simultaneously with minimal pulse distortion.
This document discusses and compares the classical/transfer function approach and the state space/modern control approach for modeling dynamical systems. The classical approach uses Laplace transforms and transfer functions in the frequency domain, while the state space approach uses matrices to represent systems of differential equations directly in the time domain. The state space approach can model nonlinear, time-varying, and multi-input multi-output systems and considers initial conditions, while the classical approach is limited to linear time-invariant single-input single-output systems. The document provides examples of modeling circuits using the state space representation.
A Klystron is a vacuum tube that can be used either as a generator or as an amplifier or as an oscillator, at microwave frequencies.The Klystron is a linear beam device; that is, the electron flow is in a straight line focused by an axial magnetic field.
This document provides information about diffusion and drift currents. It includes the topic, which is diffusion and drift currents. It also lists the degree, which is a BS(Hons) in Physics from the University of Education Township in Lahore. Finally, it provides references for additional reading on the topics of solid state physics, concepts of modern physics, solid state electronic devices, and the differences between diffusion current and drift current.
SOLUTION MANUAL OF WIRELESS COMMUNICATIONS BY THEODORE S RAPPAPORTvtunotesbysree
This document appears to be a solution manual for a textbook on wireless communications by Theodore S. Rappaport. The solution manual likely provides answers and explanations to problems presented in Rappaport's textbook on wireless communications to help students learn and understand the concepts and applications of wireless communication technology.
Raman spectroscopy is a spectroscopic technique used to observe vibrational, rotational, and other low-frequency modes in a system. It relies on inelastic scattering, or Raman scattering, of monochromatic light, usually from a laser in the visible, near infrared, or near ultraviolet range. The laser light interacts with molecular vibrations, phonons or other excitations in the system, resulting in the energy of the laser photons being shifted up or down. The shift in energy gives information about the vibrational modes in the system. Raman spectroscopy provides a fingerprint by which molecules can be identified. It provides information about chemical structure, crystallinity, and molecular interactions.
This lab covers pulse amplitude modulation and demodulation. Students will modulate a pulse train with a modulating signal and observe the output waveform. They will also demodulate the modulated signal and measure the recovered modulating signal. The objectives are to learn how to perform PAM modulation and demodulation and calculate the modulation index. The hardware required includes transistors, integrated circuits, resistors, capacitors, an oscilloscope, and pulse generator. The theory section describes how PAM works by varying the amplitude of pulses based on the modulating signal. Demodulation recovers the modulating signal using a low pass filter. Students will set up the modulation and demodulation circuits, take readings, and answer post-lab questions.
1. Power dividers are microwave components that divide input power between output ports. Common types include T-junction, Wilkinson, and multi-section broadband dividers. T-junction dividers can be lossless or lossy. Wilkinson dividers provide isolation between output ports.
2. Directional couplers are 4-port networks that divide power between through and coupled ports. They use quarter-wave length lines and even-odd mode analysis. Voltage ratios define coupling factors. Multisection designs provide broadband operation.
3. Hybrids like the quadrature and ring hybrids are 90 or 180 degree hybrids based on symmetric/asymmetric port designs and even-odd mode analysis to provide specific scattering
The document discusses digital communication systems. It provides examples of digital communication including an email sent to invite team members to a meeting. It then explains the key building blocks of a digital communication system including the input source, source encoder, channel encoder, digital modulator, channel, digital demodulator, channel decoder, source decoder and output transducer. The document also discusses channels used for digital communication, causes of signal loss, and comparisons between digital and analog communication systems.
This presentation covers noise performance of Continuous wave modulation systems; It explains modelling of white noise , noise figure of DSB-SC, SSB, AM, FM system
The document discusses various types of small antennas that can be used for EnOcean-based products, including quarter-wave monopole antennas, helical antennas, chip antennas, and PCB antennas. It emphasizes that the antenna design is critical for radio performance and range. The antenna and a sufficiently sized ground plane form a resonant circuit. Common pitfalls in antenna design are an undersized ground plane or traces and components placed too close to the antenna.
Photomultiplier tubes are highly sensitive light detectors that amplify weak light signals through the photoelectric effect and secondary electron emission. They consist of a photocathode and multiple dynodes inside an evacuated glass tube, with each dynode at a progressively more positive voltage than the last. When light hits the photocathode, emitted primary electrons trigger the release of multiple secondary electrons at each dynode, resulting in electron multiplication and a detectable output current. This amplification process enables a single photon to produce around 107 electrons, making photomultiplier tubes widely used as light detectors in applications like spectroscopy.
The document summarizes the Kronig-Penny model, which models an electron in a one-dimensional periodic potential. It describes how the potential is a periodic square wave, allowing the Schrodinger equation to be solved analytically. It then shows the solution of the Schrodinger equation, expressing the eigenfunctions as a linear combination of periodic functions with a periodicity of the potential width. By applying boundary conditions and the translation operator over multiple periods, it derives an expression for the allowed wavevectors and thus the dispersion relation of the model.
The document discusses electromagnetic boundary conditions between two different media. It states that while electromagnetic quantities vary smoothly within a homogeneous medium, they can be discontinuous at boundaries between dissimilar media. The document then derives and explains the boundary conditions for the electric and magnetic fields at such interfaces. Specifically, it shows that the tangential components of E and B are continuous, while the normal components of D and B are continuous, but the normal component of H is discontinuous and depends on the relative permeability of the two media.
This document is Sakib Hussain's vocational training report from his 2-week training at All India Radio Kolkata. It details his training experiences at 4 centers: Akash Bani Bhaban (control room), Golf Green FM transmitter center, HPT Amtola (medium wave transmission), and HPT Amtola (medium and short wave transmission). The report is divided into 4 parts covering introductions to communication systems, AIR studio and broadcasting, AIR MW and SW transmission systems, and AIR FM transmission systems.
The document discusses Fourier analysis techniques. It covers topics like line spectra and Fourier series, including periodic signals and average power. Key aspects covered include phasor representation of sinusoids, convergence conditions of Fourier series, and Parseval's power theorem relating signal power to Fourier coefficients.
This document provides an overview of optical fiber communication. It begins with introducing optical fibers and how they guide light through total internal reflection. It then describes the different types of optical fibers, including step index and graded index fibers. The key elements of an optical fiber communication system are presented, along with the benefits such as high bandwidth, low loss, and electrical isolation. Applications include telecommunications networks, computing, and military systems. In conclusion, while optical fibers have some disadvantages, they have revolutionized communications due to their wide bandwidth and low transmission losses.
This document discusses various microwave sources and semiconductor devices used to generate microwave signals. It describes common microwave tubes like klystrons, magnetrons, and traveling wave tubes which use electron beams and electric/magnetic fields to generate microwaves. It also covers semiconductor microwave devices like tunnel diodes, Gunn diodes, IMPATT diodes, varactor diodes, PIN diodes, LSA diodes, and Schottky barrier diodes which generate microwaves using quantum mechanical effects in semiconductor materials. Each device type is briefly explained along with its operating principles and key applications in microwave generation and amplification.
This document discusses chromophores and auxochromes in ultraviolet-visible spectroscopy. It defines chromophores as groups that absorb in the UV-visible region and undergo π → π* or n → π* transitions. Examples include ethylenic, carbonyl, and nitrile groups. Auxochromes are groups that shift absorption to longer wavelengths by extending conjugation but do not absorb themselves, such as -OH, -NH2. Bathochromic and hypsochromic shifts change the absorption maximum wavelength while hyperchromic and hypochromic effects alter absorption intensity. Woodward-Fieser rules relate conjugation in dienes to absorption maximum.
This document discusses microwave devices, specifically directional couplers and isolators. It begins by defining microwaves and their applications such as telecommunications and radar. It then describes how directional couplers are passive devices that divide power through four ports and discusses their key figures of merit like coupling factor, isolation, and directivity. Isolators are also covered as two-port non-reciprocal devices that allow high power transmission in one direction while providing high attenuation in the opposite direction using Faraday rotation in a ferrite rod.
Principles and application of fluorescence spectroscopyruthannfrimpong1
Fluorescence spectroscopy is a technique that measures the fluorescence from samples to determine their composition. It involves exciting a sample with light and measuring the wavelengths of the light emitted. The document discusses the principles of fluorescence, the components of fluorescence spectrometers, factors that influence fluorescence measurements, and applications to food analysis like detecting heat treatments of milk and quantifying nutrients. Case studies demonstrate how fluorescence spectra can distinguish between raw and processed milk.
This document discusses different types of noise in communication systems. It defines noise and describes two main categories of noise: external noise and internal noise. External noise sources include atmospheric noise from lightning, extraterrestrial noise from space objects, and man-made noise from industrial equipment. Internal noise is generated within communication systems and includes thermal noise, shot noise, flicker noise, and intermodulation noise caused by non-linear components. The document provides detailed explanations and examples of different noise sources.
The document defines communication and its basic elements, which are a transmitter, channel, and receiver. It describes transmission media as the pathway that carries information between sender and receiver. The two main types are wired/guided media and wireless/unguided media. It also discusses analog and digital signals, periodic vs aperiodic signals, baseband vs broadband transmission, noise and signal-to-noise ratio, multiplexing, and provides short notes on communication through the ionosphere and DSB-SC and VSB modulation techniques.
This document discusses and compares the classical/transfer function approach and the state space/modern control approach for modeling dynamical systems. The classical approach uses Laplace transforms and transfer functions in the frequency domain, while the state space approach uses matrices to represent systems of differential equations directly in the time domain. The state space approach can model nonlinear, time-varying, and multi-input multi-output systems and considers initial conditions, while the classical approach is limited to linear time-invariant single-input single-output systems. The document provides examples of modeling circuits using the state space representation.
A Klystron is a vacuum tube that can be used either as a generator or as an amplifier or as an oscillator, at microwave frequencies.The Klystron is a linear beam device; that is, the electron flow is in a straight line focused by an axial magnetic field.
This document provides information about diffusion and drift currents. It includes the topic, which is diffusion and drift currents. It also lists the degree, which is a BS(Hons) in Physics from the University of Education Township in Lahore. Finally, it provides references for additional reading on the topics of solid state physics, concepts of modern physics, solid state electronic devices, and the differences between diffusion current and drift current.
SOLUTION MANUAL OF WIRELESS COMMUNICATIONS BY THEODORE S RAPPAPORTvtunotesbysree
This document appears to be a solution manual for a textbook on wireless communications by Theodore S. Rappaport. The solution manual likely provides answers and explanations to problems presented in Rappaport's textbook on wireless communications to help students learn and understand the concepts and applications of wireless communication technology.
Raman spectroscopy is a spectroscopic technique used to observe vibrational, rotational, and other low-frequency modes in a system. It relies on inelastic scattering, or Raman scattering, of monochromatic light, usually from a laser in the visible, near infrared, or near ultraviolet range. The laser light interacts with molecular vibrations, phonons or other excitations in the system, resulting in the energy of the laser photons being shifted up or down. The shift in energy gives information about the vibrational modes in the system. Raman spectroscopy provides a fingerprint by which molecules can be identified. It provides information about chemical structure, crystallinity, and molecular interactions.
This lab covers pulse amplitude modulation and demodulation. Students will modulate a pulse train with a modulating signal and observe the output waveform. They will also demodulate the modulated signal and measure the recovered modulating signal. The objectives are to learn how to perform PAM modulation and demodulation and calculate the modulation index. The hardware required includes transistors, integrated circuits, resistors, capacitors, an oscilloscope, and pulse generator. The theory section describes how PAM works by varying the amplitude of pulses based on the modulating signal. Demodulation recovers the modulating signal using a low pass filter. Students will set up the modulation and demodulation circuits, take readings, and answer post-lab questions.
1. Power dividers are microwave components that divide input power between output ports. Common types include T-junction, Wilkinson, and multi-section broadband dividers. T-junction dividers can be lossless or lossy. Wilkinson dividers provide isolation between output ports.
2. Directional couplers are 4-port networks that divide power between through and coupled ports. They use quarter-wave length lines and even-odd mode analysis. Voltage ratios define coupling factors. Multisection designs provide broadband operation.
3. Hybrids like the quadrature and ring hybrids are 90 or 180 degree hybrids based on symmetric/asymmetric port designs and even-odd mode analysis to provide specific scattering
The document discusses digital communication systems. It provides examples of digital communication including an email sent to invite team members to a meeting. It then explains the key building blocks of a digital communication system including the input source, source encoder, channel encoder, digital modulator, channel, digital demodulator, channel decoder, source decoder and output transducer. The document also discusses channels used for digital communication, causes of signal loss, and comparisons between digital and analog communication systems.
This presentation covers noise performance of Continuous wave modulation systems; It explains modelling of white noise , noise figure of DSB-SC, SSB, AM, FM system
The document discusses various types of small antennas that can be used for EnOcean-based products, including quarter-wave monopole antennas, helical antennas, chip antennas, and PCB antennas. It emphasizes that the antenna design is critical for radio performance and range. The antenna and a sufficiently sized ground plane form a resonant circuit. Common pitfalls in antenna design are an undersized ground plane or traces and components placed too close to the antenna.
Photomultiplier tubes are highly sensitive light detectors that amplify weak light signals through the photoelectric effect and secondary electron emission. They consist of a photocathode and multiple dynodes inside an evacuated glass tube, with each dynode at a progressively more positive voltage than the last. When light hits the photocathode, emitted primary electrons trigger the release of multiple secondary electrons at each dynode, resulting in electron multiplication and a detectable output current. This amplification process enables a single photon to produce around 107 electrons, making photomultiplier tubes widely used as light detectors in applications like spectroscopy.
The document summarizes the Kronig-Penny model, which models an electron in a one-dimensional periodic potential. It describes how the potential is a periodic square wave, allowing the Schrodinger equation to be solved analytically. It then shows the solution of the Schrodinger equation, expressing the eigenfunctions as a linear combination of periodic functions with a periodicity of the potential width. By applying boundary conditions and the translation operator over multiple periods, it derives an expression for the allowed wavevectors and thus the dispersion relation of the model.
The document discusses electromagnetic boundary conditions between two different media. It states that while electromagnetic quantities vary smoothly within a homogeneous medium, they can be discontinuous at boundaries between dissimilar media. The document then derives and explains the boundary conditions for the electric and magnetic fields at such interfaces. Specifically, it shows that the tangential components of E and B are continuous, while the normal components of D and B are continuous, but the normal component of H is discontinuous and depends on the relative permeability of the two media.
This document is Sakib Hussain's vocational training report from his 2-week training at All India Radio Kolkata. It details his training experiences at 4 centers: Akash Bani Bhaban (control room), Golf Green FM transmitter center, HPT Amtola (medium wave transmission), and HPT Amtola (medium and short wave transmission). The report is divided into 4 parts covering introductions to communication systems, AIR studio and broadcasting, AIR MW and SW transmission systems, and AIR FM transmission systems.
The document discusses Fourier analysis techniques. It covers topics like line spectra and Fourier series, including periodic signals and average power. Key aspects covered include phasor representation of sinusoids, convergence conditions of Fourier series, and Parseval's power theorem relating signal power to Fourier coefficients.
This document provides an overview of optical fiber communication. It begins with introducing optical fibers and how they guide light through total internal reflection. It then describes the different types of optical fibers, including step index and graded index fibers. The key elements of an optical fiber communication system are presented, along with the benefits such as high bandwidth, low loss, and electrical isolation. Applications include telecommunications networks, computing, and military systems. In conclusion, while optical fibers have some disadvantages, they have revolutionized communications due to their wide bandwidth and low transmission losses.
This document discusses various microwave sources and semiconductor devices used to generate microwave signals. It describes common microwave tubes like klystrons, magnetrons, and traveling wave tubes which use electron beams and electric/magnetic fields to generate microwaves. It also covers semiconductor microwave devices like tunnel diodes, Gunn diodes, IMPATT diodes, varactor diodes, PIN diodes, LSA diodes, and Schottky barrier diodes which generate microwaves using quantum mechanical effects in semiconductor materials. Each device type is briefly explained along with its operating principles and key applications in microwave generation and amplification.
This document discusses chromophores and auxochromes in ultraviolet-visible spectroscopy. It defines chromophores as groups that absorb in the UV-visible region and undergo π → π* or n → π* transitions. Examples include ethylenic, carbonyl, and nitrile groups. Auxochromes are groups that shift absorption to longer wavelengths by extending conjugation but do not absorb themselves, such as -OH, -NH2. Bathochromic and hypsochromic shifts change the absorption maximum wavelength while hyperchromic and hypochromic effects alter absorption intensity. Woodward-Fieser rules relate conjugation in dienes to absorption maximum.
This document discusses microwave devices, specifically directional couplers and isolators. It begins by defining microwaves and their applications such as telecommunications and radar. It then describes how directional couplers are passive devices that divide power through four ports and discusses their key figures of merit like coupling factor, isolation, and directivity. Isolators are also covered as two-port non-reciprocal devices that allow high power transmission in one direction while providing high attenuation in the opposite direction using Faraday rotation in a ferrite rod.
Principles and application of fluorescence spectroscopyruthannfrimpong1
Fluorescence spectroscopy is a technique that measures the fluorescence from samples to determine their composition. It involves exciting a sample with light and measuring the wavelengths of the light emitted. The document discusses the principles of fluorescence, the components of fluorescence spectrometers, factors that influence fluorescence measurements, and applications to food analysis like detecting heat treatments of milk and quantifying nutrients. Case studies demonstrate how fluorescence spectra can distinguish between raw and processed milk.
This document discusses different types of noise in communication systems. It defines noise and describes two main categories of noise: external noise and internal noise. External noise sources include atmospheric noise from lightning, extraterrestrial noise from space objects, and man-made noise from industrial equipment. Internal noise is generated within communication systems and includes thermal noise, shot noise, flicker noise, and intermodulation noise caused by non-linear components. The document provides detailed explanations and examples of different noise sources.
The document defines communication and its basic elements, which are a transmitter, channel, and receiver. It describes transmission media as the pathway that carries information between sender and receiver. The two main types are wired/guided media and wireless/unguided media. It also discusses analog and digital signals, periodic vs aperiodic signals, baseband vs broadband transmission, noise and signal-to-noise ratio, multiplexing, and provides short notes on communication through the ionosphere and DSB-SC and VSB modulation techniques.
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.
Lecture 1 introduction and signals analysistalhawaqar
This document provides an introduction to communication systems and signal analysis. It discusses key components of a communication system including the information source, transmitter, channel, receiver and information user. It also describes different types of communication channels and various analog and digital modulation techniques. The document further discusses noise sources in communication channels including natural and man-made noise. It introduces concepts of time and frequency domains and Fourier analysis which are important for signal analysis in communication systems.
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
This document discusses different types of noise that can affect communication systems. It describes two main categories of noise: external noise and internal noise. External noise comes from sources outside the system, such as atmospheric effects, extra-terrestrial sources like the sun, and man-made industrial sources. Internal noise is generated within the system itself and includes thermal noise, shot noise, transit time noise, and other minor sources. The document provides detailed explanations and examples of different noise types in communication systems.
This document discusses electronic noise issues and electromagnetic compatibility (EMC). It provides examples of noise issues that have caused accidents or malfunctions in various systems. It explains that as electronic devices have become more prevalent, both suppressing noise generated by devices and protecting against incoming noise is important for EMC. It discusses different types of noises and noise transfer pathways. It also summarizes EMC standards around the world and the key aspects of EMC, including electromagnetic interference (EMI) suppression and electromagnetic susceptibility (EMS) protection. The document provides an overview of noise control techniques and components used to achieve EMC.
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.
Thermal noise from components and the environment is a major source of noise in satellite communication systems. Noise comes from internal components as well as external sources like the sun, atmosphere, and space. The signal-to-noise ratio indicates the strength of the signal relative to noise, with a higher ratio desired. Forward error correction, adaptive equalization, and diversity techniques can help compensate for noise and other issues like fading that affect signal quality. Maintaining stability, power supply, and operating in the harsh environment of space present ongoing challenges for satellite systems.
Lecture-01 analog and digital communication.pptxMdShafiMahmud
To introduce with basic communication systems.
Various Amplitude modulation and demodulation systems
Various Angle modulation and demodulation systems
Basics of Noise theory and performance of various receivers.
Design modulation and optimum demodulation and detection methods for digital communications over an AWGN channel.
Calculate the error rate performance for a number of modulation schemes in AWGN environments
This document discusses the key functional elements of a communication system including the input transducer, transmitter, channel, receiver, and output transducer. It then provides details on each element. Specifically, it explains that the transmitter performs modulation to couple the message to the channel for various reasons. It also describes different types of channels including electromagnetic wave propagation channels, guided electromagnetic wave channels, and optical channels. Finally, it discusses various sources of noise and degradation that can impact communication systems such as thermal noise, shot noise, fading, multipath, and fiber optic dispersion.
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
The document discusses various parts of the electromagnetic spectrum including radio waves, infrared, ultraviolet, visible light, x-rays, and gamma rays. It provides details on the wavelength ranges and common applications of each type of electromagnetic radiation. Examples of applications discussed include GPS, FM/AM radio, TV broadcasting, microwave ovens, MRI, radar, RFID, and radio telescopes. Harmful effects of electromagnetic radiation generally increase with higher frequency and energy.
The document discusses the differences between baseband and broadband transmissions. It explains that baseband transmits a single data stream at a time using digital signals, while broadband transmits multiple data streams simultaneously using analog signals. It also discusses sources of transmission impairment including attenuation, distortion, and noise such as thermal noise and crosstalk.
1. This document discusses the electromagnetic spectrum, which includes electromagnetic waves ranging from radio waves to gamma rays. It describes the key properties and applications of different types of electromagnetic waves.
2. Students are instructed to read through the powerpoint presentation on electromagnetic waves and attempt an EM wave quiz within 60 minutes. The quiz grades will count towards their semester assessment.
3. The presentation covers the main components of the electromagnetic spectrum, the properties of all EM waves, and discusses the role and applications of different EM waves like radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. Students are provided tips to remember the EM spectrum and visible light spectrum.
The document discusses various sources and types of noise in communication systems and instrumentation. It provides details on fundamental, environmental, and instrumental noise. The major types of fundamental noise are thermal, shot, and flicker noise. Thermal noise originates from thermally induced motions in charge carriers and is represented by a formula involving resistance, temperature, and bandwidth. Shot noise arises when current involves the movement of charged particles across a junction, like at a pn interface. Flicker noise is associated with crystal surface defects and decreases with increasing frequency. Hardware techniques for improving signal-to-noise ratio include filtering, grounding/shielding, difference amplifiers, and analog filtering. Narrowing bandwidth and lowering resistance/temperature can reduce thermal noise
OBT751 Analytical methods Instrumentation materialsMercy Joseph
Instrumental methods of analysis have several advantages over chemical methods, including requiring only small sample sizes, being faster, and being able to analyze complex mixtures. The basic functions of instrumental analysis are signal generation, transduction, amplification, and presentation. Instrumental techniques are divided into spectroscopy, electrochemistry, and chromatography. Noise in instrumental analysis can come from chemical, instrumental, thermal, shot, flicker, or environmental sources. Hardware techniques can help reduce environmental, flicker, and transducer noise through methods like filters, choppers, shields, modulators, and synchronous detection.
Radio uses parts of the electromagnetic spectrum to transmit audio signals. AM radio uses amplitude modulation to vary the strength of radio carrier waves to encode audio information, while FM radio uses frequency modulation to vary the frequency of carrier waves. AM radio has greater coverage range but poorer audio quality and is more susceptible to interference than FM radio. The key differences are that AM modulates amplitude while FM modulates frequency, FM can filter out interference better, and FM provides higher quality stereo audio over greater distances.
How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
Reimagining Your Library Space: How to Increase the Vibes in Your Library No ...Diana Rendina
Librarians are leading the way in creating future-ready citizens – now we need to update our spaces to match. In this session, attendees will get inspiration for transforming their library spaces. You’ll learn how to survey students and patrons, create a focus group, and use design thinking to brainstorm ideas for your space. We’ll discuss budget friendly ways to change your space as well as how to find funding. No matter where you’re at, you’ll find ideas for reimagining your space in this session.
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.
हिंदी वर्णमाला पीपीटी, hindi alphabet PPT presentation, hindi varnamala PPT, Hindi Varnamala pdf, हिंदी स्वर, हिंदी व्यंजन, sikhiye hindi varnmala, dr. mulla adam ali, hindi language and literature, hindi alphabet with drawing, hindi alphabet pdf, hindi varnamala for childrens, hindi language, hindi varnamala practice for kids, https://www.drmullaadamali.com
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
How to Build a Module in Odoo 17 Using the Scaffold MethodCeline George
Odoo provides an option for creating a module by using a single line command. By using this command the user can make a whole structure of a module. It is very easy for a beginner to make a module. There is no need to make each file manually. This slide will show how to create a module using the scaffold method.
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.
Leveraging Generative AI to Drive Nonprofit InnovationTechSoup
In this webinar, participants learned how to utilize Generative AI to streamline operations and elevate member engagement. Amazon Web Service experts provided a customer specific use cases and dived into low/no-code tools that are quick and easy to deploy through Amazon Web Service (AWS.)
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
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
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.
1. MATRUSRI ENGINEERING COLLEGE
DEPARTMENT OF ELECTRONICS AND COMMUNICATION
ENGINEERING
SUBJECT NAME: ANALOG COMMUNICATIONS
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: Understand analog communication system
CO2: Compare and analyze analog modulation techniques
CO3: Calculate noise performance of analog modulation techniques
CO4: Design AM and FM receivers
CO5: Differentiate between pulse modulation techniques & continuous
modulation techniques.
MATRUSRI
ENGINEERING COLLEGE
3. SYLLABUS
UNIT I- Linear Modulation schemes: Need for modulation,
conventional 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 V- Noise Sources and types
MATRUSRI
ENGINEERING COLLEGE
S. No. Topic(S)
No.
of Hrs
Relevant
COs
Text Book/
Reference
Book
1. Noise Sources and types: Atmospheric noise, Shot
noise and thermal noise
1 CO3 T1,T2,T3
2. Noise temperature. Noise in two-port network:
noise figure, equivalent noise temperature and noise
bandwidth. Noise figure and equivalent noise
temperature of cascade stages
1 CO3 T1,T2,T3
3. Narrow band noise representation. 1 CO3 T1,T2,T3
4. S/N ratio and Figure of merit calculations in AM,
DSB-SC, SSB and FM systems,
3 CO3 T1,T2,T3
5. Pre-Emphasis and De-Emphasis, 1
Total 07
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:
UNIT V- NOISE
Discuss the different types of Noises and noise source, Narrowband Noise In phase and
quadrature phase components and its Properties.
Analyze the Noise in DSB and SSB System, Noise in AM System, Noise in Angle
Modulation System, Pre-emphasis and de-emphasis circuits
MATRUSRI
ENGINEERING COLLEGE
Initially Noise Definition and Types of noises, Noise temperature are discussed.
Then Noise in two port Network-Noise figure, equivalent temperature ,Noise
bandwidth are discussed. Then noise figure and noise temperature of cascaded
stages are calculated .finally students will calculate S/N ratio and Figure of merit
calculations for AM ,DSB-SC,SSB-SC and FM systems. Finally Pre-emphasis and De-
emphasis concepts are also discussed.
9. CONTENTS:
5.1. Noise sources and types:
- Atmospheric noise,
- Shot noise
- Thermal noise.
5.2. Noise temperature, noise in two-port network: noise figure, equivalent noise temperature,
noise bandwidth, Noise figure and equivalent noise temperature of cascade stages.
5.3. Narrow band noise representation.
5.4. S/N ratio and figure of merit calculations in: AM, DSB-SC, SSB and FM systems
5.5. Pre-emphasis and de-emphasis
OUTCOMES:
Discuss the different types of Noises and noise source, Narrowband Noise In phase and
quadrature phase components and its Properties.
Analyze the Noise in DSB and SSB System, Noise in AM System, Noise in Angle Modulation
System, Pre-emphasis and de-emphasis circuits
UNIT V- NOISE
MATRUSRI
ENGINEERING COLLEGE
10. CONTENTS:
5.1. Noise sources and types:
- Atmospheric noise,
- Shot noise
- Thermal noise.
OUTCOMES:
Discuss the different types of Noises and noise source, Narrowband Noise In phase and
quadrature phase components and its Properties.
MODULE-1
MATRUSRI
ENGINEERING COLLEGE
11. Noise is an unwanted signal which interferes with the original message signal and corrupts the
parameters of the message signal. This alteration in the communication process, leads to the
message getting altered. It is most likely to be entered at the channel or the receiver.
The noise signal can be understood by taking a look at the following example.
5.1. Noise sources and types
MATRUSRI
ENGINEERING COLLEGE
Most common examples of noise are −
•Hiss sound in radio receivers
•Buzz sound amidst of telephone
conversations
•Flicker in television receivers, etc.
12. Types of noise:
There are two main ways in which noise is produced. One is through some external source , other is
created by an internal source.
External source: This noise is produced by the external sources which may occur in the medium or
channel of communication, usually. This noise cannot be completely eliminated. The best way is to
avoid the noise from affecting the signal.
Most common examples of this type of noise are −
Atmospheric noise (due to irregularities in the atmosphere). Extra-terrestrial noise, such as solar
noise and cosmic noise, Industrial noise.
Internal source:
This noise is produced by the receiver components while functioning. The components in the circuits,
due to continuous functioning, may produce few types of noise. This noise is quantifiable. A proper
receiver design may lower the effect of this internal noise.
Most common examples of this type of noise are −
• Thermal agitation noise (johnson noise or electrical noise).
• Shot noise (due to the random movement of electrons and holes).
• Transit-time noise (during transition).
• Miscellaneous noise is another type of noise which includes flicker, resistance effect and mixer
generated noise, etc.
5.1. Noise sources and types
MATRUSRI
ENGINEERING COLLEGE
13. Atmospheric noise or static is caused by lighting discharges in thunderstorms and other
natural electrical disturbances occurring in the atmosphere. These electrical impulses are
random in nature. Hence the energy is spread over the complete frequency spectrum used for
radio communication.
Extraterrestrial noise:
(I)solar noise: This is the electrical noise emanating from the sun. Under quite conditions, there is a
steady radiation of noise from the sun.
This results because sun is a large body at a very high temperature (exceeding 6000°C on the
surface), and radiates electrical energy in the form of noise over a very wide frequency spectrum
including the spectrum used for radio communication.
The intensity produced by the sun varies with time. In fact, the sun has a repeating 11-year noise
cycle. During the peak of the cycle, the sun produces some amount of noise that causes tremendous
radio signal interference, making many frequencies unusable for communications.
(Ii)Galatic noise (or)cosmic noise: Distant stars are also suns and have high temperatures. These
stars, therefore, radiate noise in the same way as our sun. The noise received from these distant stars
is thermal noise (or black body noise) and is distributing almost uniformly over the entire sky. We
also receive noise from the center of our own galaxy (the milky way) from other distant galaxies and
from other virtual point sources such as quasars and pulsars.
5.1. Noise sources and types
MATRUSRI
ENGINEERING COLLEGE
14. iii. Man-made noise (industrial noise) is meant the electrical noise produced by such sources as
automobiles and aircraft ignition, electrical motors and switch gears, leakage from high voltage lines,
fluorescent lights, and numerous other heavy electrical machines. Such noises are produced by the
arc discharge taking place during operation of these machines.
Such man-made noise is most intensive in industrial and densely populated areas. Man-made noise
in such areas far exceeds all other sources of noise in the frequency range extending from about 1
MHz to 600 MHz
5.1. Noise sources and types
MATRUSRI
ENGINEERING COLLEGE
INTERNALNOISE:
i. Thermal noise conductors contain a large number of free electrons and ions strongly bound
by molecular forces. The ions vibrate randomly about their normal (average) positions,
however, this vibration being a function of the temperature. Continuous collisions between the
electrons and the vibrating ions take place.
Thus there is a continuous transfer of energy between the ions and electrons. This is the
source of resistance in a conductor. The movement of free electrons constitutes a current
which is purely random in nature and over a long time averages zero. There is a random
motion of the electrons which give rise to noise voltage called thermal noise. Thus noise
generated in any resistance due to random motion of electrons is called thermal noise or
white or johnson noise relate the noise power generated by a resistor to be proportional to
its absolute temperature.
15. Thermal Noise: Noise power is also proportional to the bandwidth over which it is measured.
Pn∝ T
Pn∝ B
Pn = KTB
where Pn = maximum noise power output of a resistor.
K = boltzmann’s constant= 1.38 x10^-23 joules / kelvin.
T = absolute temperature,
B = bandwidth over which noise is measured
Thermal noise is often referred to as ‘white
noise’ because it has a uniform ‘spectral density
5.1. Noise sources and types
MATRUSRI
ENGINEERING COLLEGE
This thermal noise may be represented by an equivalent
circuit as shown
16. Shot Noise:
Shot noise was originally used to describe noise due to random fluctuations in electron emission from
cathodes in vacuum tubes (called shot noise by analogy with lead shot).
Shot noise also occurs in semiconductors due to the liberation of charge carriers.
For pn junctions the mean square shot noise currentis
5.1. Noise sources and types
MATRUSRI
ENGINEERING COLLEGE
Where I is the direct current as the Pn junction (amps) saturation current
(amps)
• “Io” is the electron charge = 1.6 x 10-19coulombs
• B is the effective noise bandwidth(Hz)
• Shot noise is found to have a uniform spectral density as for “thermal noise”
17. CONTENTS:
5.2. Noise temperature, noise in two-port network: noise figure, equivalent noise
temperature, noise bandwidth, Noise figure and equivalent noise temperature of
cascade stages.
OUTCOMES:
Discuss the Noise temperature, noise bandwidth and Noise figure
MODULE-2
MATRUSRI
ENGINEERING COLLEGE
18. Two-Port Network:
The signal to noise ratio is given by Signal power to Noise power
5.2.Noise Figure &Equivalent Noise Temp .of 2-port Network
MATRUSRI
ENGINEERING COLLEGE
10
.
.
( ) 10log( )
. .
( )
. .
. .
( )
. .
i
i
i
o
o
o
Signal Power
SNR
Noise Power
signalpower
SNR
NoisePower
S
input signal power
SignaltoNoiseRatio
input Noise Powert N
S
output signal power
SignaltoNoiseRatio
output Noise Powert N
NoiseFigu
0
( )
( )
i
o
o
i
i
S
SNR N
re
S
SNR
N
19. (i) for noise less system sno=sni
therefore noise figure=1
(ii) for noisy system sno>sni noise figure is nf>1
total noise power density at the output is the sum of the noise power density(sno) due to the input
source sni and noise power density contributed by the system sns
(sno)= sni+ sns
5.2.Noise Figure &Equivalent Noise Temp .of 2-port Network
MATRUSRI
ENGINEERING COLLEGE
Therefore Noise figure is
1
No NI Ns Ns
NI NI NI
S S S S
NF
S S S
Noise Figure in terms of Noise Temperature
The noise figure in terms of equivalent input noise temperature can be expressed
1
Ts
NF
T
Ts=Noise temperature of the system
T=Noise temperature of the source
( 1)
Tc T NF
20. Noise figure in cascaded stages:
let the two stage amplifier connected in cascade. Then the overall noise figure of the
cascade connection in terms of the noise figure of the individual amplifier or 2-ports
5.2.Noise Figure &Equivalent Noise Temp .of 2-port Network
MATRUSRI
ENGINEERING COLLEGE
. . .
( ) .
. . . . . .
Ni No
Ni
G Actual output noise power
i NF
G Noise output power if the amplifier in
Available gain G
Available input noise power KT(Δf)
Available Output Noise Power NF.G.KT.(S Δf)
Power
Gain(G1)
NF=F1
Power
Gain(G2)
NF=F2
(F1-1)KT(Δf)
KT(Δf)
(F2-1)KT(Δf)
F1.KT(Δf)G1G2
+
(F2-1)KT(Δf)G2
21. NOISE FIGURE IN CASCADED STAGES:
5.2.Noise Figure &Equivalent Noise Temp .of 2-port Network
MATRUSRI
ENGINEERING COLLEGE
1 2 1
1 2 2
1 2
2 1
1
1
. . .
. . ( )
. . .assuming.the.amplifier
( )G G ( )G
. . ( )
( )G G
( )
Actual Output Noise Power
Overall Noise Figure NF
Output Noise Power
Overall Noise Figure NF
F
N
F KT f F KT
F F
f
KT f
G
It may be extended to any no of amplifiers connected in cascade
3 1
2 1 4 1
1
1 1 2 1 2 3
( )
( ) ( )
. . .
F
F F
NF F
G G G G G G
Quadrant noise temperature of cascaded amplifiers
Individual stages have equivalent noise temperature To1,To2,To3,….and available power gains
G1,G2,G3,….Let the Room temperature be T.If the equivalent noise temperature of cascaded
connection is say Te.
1 1 2
1 1 2
1 2 3
1 1
1 2 3
Te Te Te Te
To To GTo G G To
Te Te Te
Te
G G G
23. NARROW BAND NOISE REPRESENTATION:
SINGLE –SIDE BAND SUPPRESSED CARRIER (SSB-SC):
The front end of the receiver will be designed to have a bandwidth just equal to the bandwidth of the
transmitted signal
5.3. Narrow band Noise Representation
MATRUSRI
ENGINEERING COLLEGE
t
w
t
m
t
w
t
m
A
t
m
SC
SSB c
c
c
c sin
).
(
cos
).
(
2
1
)
(
: ^
+ BPF Detector output
k.mc(t)
nw(t)
24. 5.3. Narrow band Noise Representation
MATRUSRI
ENGINEERING COLLEGE
)
(
2
2
t
M
K
SR
)
(
.
4
1
.
2
1
)
(
.
4
1
.
2
1
sin
).
(
cos
.
sin
).
(
).
(
.
2
cos
).
(
4
1
2
^
2
2
2
2
2
2
2
^
2
2
2
2
t
m
A
k
t
m
A
k
S
t
w
t
m
t
w
t
w
t
m
t
m
t
w
t
m
A
k
S
c
c
R
c
c
c
c
C
R
)
(
)
( 2
^
2
t
m
t
m
Since the Hilbert transform does not alter the power
where c
R A
K
A .
t
w
t
n
t
w
t
n
t
w
t
m
A
t
w
t
m
A
t
y
t
w
t
n
t
w
t
n
t
n
t
n
t
Km
t
y
c
q
c
i
c
R
c
R
c
q
c
i
c
sin
)
(
cos
)
(
sin
).
(
2
1
cos
).
(
2
1
)
(
sin
).
(
cos
).
(
)
(
)
(
)
(
)
(
^
25. .
5.3. Narrow band Noise Representation
MATRUSRI
ENGINEERING COLLEGE
In detector/synchronous detector y(t) is multiplied by coswct and LPF:
After LPF (with cuttoff frequency ‘w’ Hz)
2
2 2 2 2
2
2
i
..
2 w 2 w
1
( ) ( )(1 ) ( )(1 )
2 2 2
2 w 2 w
1 1 1
( )( ) ( )( )
2 2 2 2 2
1 1
( ) ( )
4 4
1 1
( ) ( )
4 4
( )
1
. ( )
2
( )
c c
R i
c c
R i
R i
R R
R R
n
T T
D SSB
Cos t Cos t
w f A m t n t
Cos t Cos t
A m t n t
A m t n t
A Zn f A m f
S S
S
N w
t
S
N
FigureofMeri
( )
1
( )
D
C
S
N
t
S
N
t
w
t
n
t
w
t
n
t
w
t
m
A
t
w
t
m
A
t
z
t
w
t
y
t
z
c
q
c
i
c
R
c
R
c
2
sin
).
(
cos
).
(
2
sin
).
(
4
1
cos
).
(
2
1
)
(
cos
).
(
)
(
2
^
2
26. .
5.3. Narrow band Noise Representation
MATRUSRI
ENGINEERING COLLEGE
Consider detector is synchronous detector , Then the modulated or transmitted signal is
given by :
( ) ( )cosw ..
c c c
m t A m t t DSBSC signal
Then received signal is K.mi(t)
2 2
2 2
. . ( ).cos
.m(t)cos
Re . . ( ) ( )
1
( ) .............. 2
2
. . .det ( ) ( )cos ( )
( )cos ( )cos ( )sin
.
.
( )
c c
R c
R
R
R c
R c i c q
i
i
c
R
K A m t w t
A w t
ceived signal power S K m t
m t A DSBSC BW w
Input to the ector y t A m t w t n t
A m t w t n t w t n t w t
A m
m t
K t
t n
m
c
( ) cos ( )sin
.. det .. . ( ).by.cosw t
i c q c
t w t n t w t
The synchronous ector multiplies y t
27. 5.3. Narrow band Noise Representation
MATRUSRI
ENGINEERING COLLEGE
c
c
2
c
cosw t
( ) ( ) cos ( )sin cosw t
( ) ( ) cos ( )sin .cosw t
1 1 1
( ) ( ) ( ) ( ) 2 ( )sin 2
2 2 2
.. . . .
1
( )
.
( ) ( )
2
.
R i c q c
R i c q c
R i R i c q c
R i
A m t n t w t n t w t
A m t n t w t n t w t
A m t n t A m t n t Cos w t n t w t
The output o
Z t
f LPF is
W t
y t
A m t n t
2 2
2
( )
( ) 2
c R R
D i T
A m t S S
S
N n t W
28. CONTENTS:
5.4. S/N ratio and figure of merit calculations in: DSB-SC, SSB
OUTCOME:
Analyze the Noise in DSB and SSB System,
MODULE-4
MATRUSRI
ENGINEERING COLLEGE
29. Input of the receiver Si(t)= Ac m(t)cos2π fc t+ Ni(t)
Mean square value of the signal
S/N Ratio and Figure of Merit Calculations in DSB-SC
MATRUSRI
ENGINEERING COLLEGE
S/N Ratio and Figure of Merit Calculations in DSB-SC
DSB-SC signal =Ac m(t)cos2π fc t
2
2
( . )
c c
Si t A m t cos f t
Input band pass Noise can be
2 2 2
( ) ( ) 2 ( )sin 2
( ) ( ) ( )
i i c q c
i q I
N t n t cos f t n t f t
Ni n t n t n t
At Demodulator/Detector :DSB-SC signal is multiplied by carrier signal Cos2πfct
=Ac m(t). Cos2f ct. Cos2f ct
2
( ) 1 cos4
2
2 c
c
c
m t cos f t
A
t
m f
t
Output of LPF:
( )
2
c
A m t
So t
2
)
(
2
2
t
m
A
S c
i
Input signal Power
30. .
S/N Ratio and Figure of Merit Calculations in DSB-SC
MATRUSRI
ENGINEERING COLLEGE
The output Signal Power:
2
( ) ( ) 2
( ) 2 ( )sin 2 . 2
( )
( )
sin 4
2
1
( ) (
1 cos4
2
cos4
) ( ) sin 4
2
o c
i c q c c
q
i
c c
i i c q c
n t n t cos f t
n t cos f t n t f t cos f t
n t
n t
f t f t
n t n t f t n t f t
After LPF
2 2
1
( )
2
1 1
( ) ( )
4 4
1
4
o i
o o i I
o
I
N t n t
N n t n t N
N
N
8
)
(
.
)
(
2
2
)
(
.
)
(
2
2
2
t
m
A
t
S
t
m
A
t
S
c
o
c
o
Figure of Merit:
i
S
1
4
1
4
1
i
SNR
SNR
N
N
S
S
O
i
o
i
o
31. .
S/N Ratio and Figure of Merit Calculations in SSB-SC
MATRUSRI
ENGINEERING COLLEGE
Single Sideband Suppressed carrier(SSB-SC):
t
f
t
m
t
f
t
m
A
SC
SSB c
c
c
2
sin
).
(
2
cos
).
(
2
:
)
(
2
sin
).
(
2
cos
).
(
2
t
n
t
f
t
m
t
f
t
m
A
c
c
c
Input of the Receiver + Noise
)
(
4
)
(
2
1
)
(
2
1
4
2
2
2
^
2
2
t
m
A
t
m
t
m
A
S c
c
i
Input signal Power is
At Input of Demodulator or Detector
t
f
t
f
t
m
t
f
t
m
A
t
S c
c
c
c
d
2
cos
.
2
sin
).
(
2
cos
).
(
2
)
(
^
t
f
t
m
A
t
f
t
m
A
c
c
c
c
^
4
sin
).
(
4
]
2
cos
1
).[
(
4
32. S/N Ratio and Figure of Merit Calculations in SSB-SC
MATRUSRI
ENGINEERING COLLEGE
After LPF: )
(
.
4
)
( t
m
A
t
S c
o
Output signal Power of the Demodulator:
)
(
.
16
2
2
t
m
A
S c
o
i
S
4
1
4
1
i
o
S
S
Figure of Merit:
1
i
o
i
o
i
i
o
o
N
N
S
S
N
S
N
S
33. CONTENTS:
5.4. S/N ratio and figure of merit calculations in: AM systems
OUTCOME:
Analyze the Noise in AM System
MODULE-5
MATRUSRI
ENGINEERING COLLEGE
34. .
Noise In Amplitude Modulation (AM) Scheme
MATRUSRI
ENGINEERING COLLEGE
In a conventional amplitude modulated (AM)wave both sidebands and the carrier are transmitted.
The received signal has the term :
S(t)=Ac(1+Kam(t))cos2 fct
Envelope Detector/Envelope Detection:
It consists of simply a non linear device followed by a LPF.
Si(t)= Ac(1+Kam(t))cos2 fct + ni(t)
The mean square signal power Si and noise Power Ni
2
2 2
[1 ( )]
2
c
i a
A
S k m t
To compute the mean square power, so and noise power No at the output of the demodulator,
35. .
Noise In Amplitude Modulation (AM) Scheme
MATRUSRI
ENGINEERING COLLEGE
1
2 2 2
1
1 2 ( ) 2 ( )sin 2
[ 1 ( )] 2 ( )sin 2
( ). (2 ( ))
where....C(t) [[ 1 ( )] ( )
( )
( ) tan
[ 1 ( )]
i c a c I c Q c
i c a I c Q c
c
c a I Q
Q
c a I
S t A K m t cos f t n t cos f t n t f t
S t A K m t n t cos f t n t f t
k C t cos f t t
A K m t n t n t
n t
t
A K m t n t
The output of the envelope detector is obviously C(t).we shall now consider two cases:
a)small noise case Ac(1+Kam(t)) >> n(t)
b) Large noise case n(t) >> Ac(1+Kam(t))
36. .
Noise In Amplitude Modulation (AM) Scheme
MATRUSRI
ENGINEERING COLLEGE
a) small noise case: Ac(1+Kam(t)) >> n(t)
In this case Ac(1+Kam(t)) >> n(t)
Therefore Ac(1+Kam(t)) >> nI(t) or nQ(t)
The envelope equation can be approximated under this condition
1
2
1
2
2
1 2 1 .
( )
1
1
( )
1
1
[{ } ]
2
[1
[1
1 ( )
c a c a I
I
c a
c a
I
c a
c a
c a I
E t A K m t A K m t n t
n t
A K m t
A K m t
n t
A K m t
A K m t
A K m t n t
Ni(t)
Nq(t)
Phasor diagram for small noise Ψ(t)
37. 5.4. Noise In Amplitude Modulation (AM) Scheme
MATRUSRI
ENGINEERING COLLEGE
a) small noise case: Ac(1+Kam(t)) >> n(t)
1 ( )
( ) c a I
A K m t n
E t t
And Ψ(t)=0
It is evident that the useful signal at the output of the demodulator
So(t)=Ka Ac m(t)
ni(t)=nI(t)
2 2 2
a c
So K A m t
2
( )
o I i
N n t N
2 2 2
2 2
2 2 2
2 2
2
1
1
2
o
a c
o a
c
i a
a
i
S
K A m t
N K m t
A
S K m t
K m t
N
When µ=KaAm is the modulation index. Now the avg power of the modulating signal is
2
2
( )
2
m
A
m t
2
2
2 2
2 2 2
2
2
2 2
2
1
2
o m
a
o a m
m a m
i
a
i
S A
K
N K A
A K A
S
K
N
When µ=KaAm=1 which corresponds to 100%
modulation The max improvement in S/N that
can be achieved by 2/3
38. .
5.4 Noise In Amplitude Modulation (AM) Scheme
MATRUSRI
ENGINEERING COLLEGE
b) Large noise case : n(t) >> Ac(1+Kam(t)):
In this case n(t) >> Ac(1+Kam(t))
ni(t) and nq(t) >> Ac(1+Kam(t))
under this condition the envelope of the second signal given by:
1
2 2 2
1
2 2
1
2
1
2 2 2
1
[ 2 ]
[ ( ) 2 ]
( )[1 cos[ (t)]]
( )
( ) [ ]
(t) t
1
1
(
an ( )
1
I Q I c a
I c a
c a
I Q
I
Q
R t
R t
R t
e t n t n t n t A K m t
e t n t A K m t
A K m t
e t
n t n t
n t
n t
R t
( )[1 cos[ (t)]]
( )
( ) cos[ (t)]
( ) cos (t)) cos[ (t)]
( ) cos (t)) cos[ (t
( 1
( 1
(
)
( ]
c a
c a
c c a
c c a
R t
R
A K m t
e t
e t A K m t
e t A A K m t
e t A A K m t
t
R t
R t
R t
E(t) can be further simplified as:
39. .
5.4 Noise In Amplitude Modulation (AM) Scheme
MATRUSRI
ENGINEERING COLLEGE
B) COHERENT DETECTION:
If synchronous or coherent detector is used for demodulation of AM , it can be shown that the
same improvement in the S/N ratio will be obtained in the large noise as well as in the small
noise case:
2
2 2
[1 ( )]
2
c
i a
A
S k m t
2
( )
i i
N n t
The synchronous detector output:
2 2
( ) [( 1 2 ( ) 2
)
(1 (1
2
( )sin 2 ] 2
( ) 1 2 ( ) 2 ( )sin 2 . 2
( )
( )
( ) 1 ( ) 4 ) 4 ) sin 4
2
d c a c I c q c c
d c a c I c q c c
q
I
d c a c c c
S t A K m t cos f t n t cos f t n t f t cos f t
S t A K m t cos f t n t cos f t n t f t cos f t
n t
n t
S t A K m t cos f t cos f t f t
40. 5.4 Noise In Amplitude Modulation (AM) Scheme
MATRUSRI
ENGINEERING COLLEGE
After LPF
2
2 2
2
( )
4
( ) 1
4 4
c
o a
I
o i
A
S K m t
n t
N N
2
2
2
2 2 2
2
2 2 2
2
2
2
2
2 2 2
2
2
1
2
2
..... 1....
( )
.
3
m
o m
a
o a m
m a m
i
a
i
o
o
i
i
A
S A
K
N K A
A K A
S
K
N
S
N
when
S
N
m t
41. CONTENTS:
5.4. S/N ratio and figure of merit calculations in: FM systems
OUTCOME:
Analyze the Noise in Angle Modulation System
MODULE-6
MATRUSRI
ENGINEERING COLLEGE
42. .
5.4 Noise in FM receivers
MATRUSRI
ENGINEERING COLLEGE
BPF
Frequency
discriminator
Post Detection
filter(LPF)
FM
Noise
The angle modulated carrier is generalized form S(t) (2 ( ))
c c
A cos f t t
Message is bandlimited to W hz
The channel noise at the input of the demodulator is a bandpass noise with power spectral
density sn(f) and band limited to 2( Δf+fm)
Where Ac=unmodulated carrier component
fc=carrier frequency
Ø(t)= Instantaneous phase angle
Ø(t)=Kp.m(t)………………..for PM
Ø(t)=2πKf. ∫m(t).dt……….for FM
Noise in FM Receiver:
43. .
5.4 Noise in FM receivers
MATRUSRI
ENGINEERING COLLEGE
The noise can be expressed
( )
( ) ( ). (2
( )cos ( )sin
(t))
i c q c
c
n t
n t R t cos
n t w t n t t
f
w
t
2 2
1 ( )
(t) t
( ) ( ) ( )
an
( )
q
q
I
I
n
R t n t n t
t
n t
(2 2 . . ) ( )
(2 2 . . ) ( ). 2 t
( )
( )
i c c f
i c c f c
S t A cos f t K m t dt n t
S t A cos f t K m t dt R t cos f t
The signal present at the input of FM demodulator can be written as
Where
Resultant
R(t)
( ) ( )
t t
)
(t) (t
This can be represented by
phasor diagram
44.
5.4 Noise in FM receivers
MATRUSRI
ENGINEERING COLLEGE
The relative phase Ψ(t) is
1 ( )]
( )sin
( )
(
[ (t)
( )cos )]
[ (t)
c
R t
A
t
t t tan
R t t
Where
Ø(t)=2πKf. ∫m(t).dt
For the sake of simplicity we assume that the amp of un-modulated carrier is very large so that the
carrier to noise ratio is measured at the discriminator input is large compared to unity
Under this condition the relative phase Ψ(t) of the resultant phasor can be
0
(t)
( )
( ) ( ) sin[ ( )]
( ) 2 . 2 . .
c
t
f f
R t
t t t
A
t K m t dt K m t dt
The output of the discriminator can be written as
1 ( )
( )
2
(
( . ( ) )
)
d
d f d
K m t
d t
S t
dx
S t n t
Where nd(t) is the noise defined as
(
1
( ) ( )sin[ (t) )]
2 c
d
d
n t R t
A dt
t
45. 5.4 Noise in FM receivers
MATRUSRI
ENGINEERING COLLEGE
.
The assumption further simplifies
1
( ) [ ( )sin (t)]
2 c
d
d
n t R t
dt
A
Further written as 1
( ) [ ( )]
2 c
d s
d
n t n
A
t
dt
The discriminator output is given by kfm(t)+nd(t), when this signal is passed through LPF, the
final demodulator signal output becomes:
so(t)=kfm(t)
mean square signal power is
2 2
( )
f m
So k t
Linear filter transfer function 2
2
( )
c c
f jf
H f
A
j
A
The PSD of the quadrature component of the bandpass noise and noise output of the
demodulator is:
2
2
2
(f) ( )
( )
nq
nq
N
N
c
S f
S
H S f
f
f
S f
A
46. 5.4 Noise in FM receivers
MATRUSRI
ENGINEERING COLLEGE
2
2
2
0
nd c
f BT
f
S f A
otherwise
0
η
f
2
BT
2
BT
f
The average noise power is obtained by
integrating the PSD
Where
2
2
3
2
2
3
w
o
c w
o
c
N f df
A
w
N
A
The average signal power present at the input of the demodulator:
2
2
c
i
A
S
The average noise power at the demodulator input is 2
i
N T
2
3
2
6 ( )
o
o
i
i
S
N
W
Kf m t BT
S
N
47. .
5.4 Noise in FM receivers
MATRUSRI
ENGINEERING COLLEGE
Signal to noise ratio at the demodulator output is given by
2 2
3
2
3 (
2
)
o c
o
Kf A m t
S
N W
The signal output of the Envelope detector is given
It is interesting to compare S/N ratio at the demodulator output for FM and AM
If there signal m(t) were transmitting using AM
2 2 2
2
( )
( ) 2
o a c
o I i
S k A m t
N n t N w
The S/N at the AM demodulator o/p can be written as:
2 2 2
2
3 3 3 3
f c f m
FM
m m m
AM
So
k A k A f
No
Si f f f
Ni
For comparison we also consider
AM under most favorable condition i. e
AM with 100% modulation
In this case the amp of m(t)
becomes same as that of the carrier i.e Ac
Ka=1/Ac=1/Am AM being
amplitude of message
2
2
2
0 3
a
f
AM
o
o
FM
o
k
w
k
N
S
N
S
W
B
t
m
k
N
S a
AM
o
o
2
).
(
2
2
48. .
5.4 Noise in FM receivers
MATRUSRI
ENGINEERING COLLEGE
Threshold in FM:
The threshold effect in FM is much more pronounced then in Am
The FM signal at the demodulator input can be expressed as:
. 2 ( )) ( )
(
i c c
S t A Cos f t t n t
0
( (
(
( ) 2 ( )
( ) ( ) 2 ) ( ) 2 )
n(t) R(t) 2 ( ))
t
f
i c q c
c
t k m t dt
n t n t Cos f t n t Sin f t
Cos f t t
Where
The above equation can be written as : . 2 ( ))
( ( ) (
(2 ))
i c c c
S t A Cos f t t R t Cos f t t
The phasor diagram representing the equation
1
. 2 ( )) ( )
sin( ( ) ( ))
..... ( ) tan
( ) cos( ( ) ( ))
(
i c c
c
c
S t A Cos f t t t
A t t
where t
R t A t t
49. 5.4 Noise in FM receivers
MATRUSRI
ENGINEERING COLLEGE
For large noise case:
R(t)>>Ac the equation can be expressed as
1
1
sin( ( ) ( ))
( ) tan
( )
( ) tan sin( ( ) ( ))
( )
c
c
A t t
t
R t
A
t t t
R t
The output of the FM Demodulator is given by
( ) (2 ( ) ( ))
( ) ( )
( ) 2
d c
d c
d
S t f t t t
dt
d t d t
S t f
dt dt
50. CONTENTS:
5.5. Pre-emphasis and de-emphasis
OUTCOME:
Understand the concepts of Pre-emphasis and de-emphasis .
MODULE-7
MATRUSRI
ENGINEERING COLLEGE
51. Pre-emphasis & De-emphasis:
5.5. Pre-emphasis and de-emphasis
MATRUSRI
ENGINEERING COLLEGE
Pre-emphasis: The Boosting of the amplitude of high frequency modulating signal at
FM transmitter is called Pre-emphasis
3dB Low cut-off frequency for the pre-emphasis circuit cab be computed by
Fc=1/2πR2C
52. .
5.5. Pre-emphasis and de-emphasis
MATRUSRI
ENGINEERING COLLEGE
De-emphasis:
The Artifically Boosted High frequency signal in the process of pre-emphasis
at FM tranmitter are brought to their original amplitude levels using using
de-emphasis circuit at the FM Receiver
53. 1. (A)What are external and internal noises?
(B)Define signal to noise ratio, noise figure and equivalent noise temperature
2.Explain using phasor diagram the effect of noise on FM.
3. Calculate the system noise of a receiver that has a bandwidth of 6 mhz and an input noise
temperature of 250K to the antenna. The equivalent noise resistance of receiver is 75 ohms, the
antenna has a resistance of 72 ohms. Assume to=2900 k.
4. Explain pre-emphasis and de emphasis in FM systems?
5. Explain noise in angle modulation systems?
Assignment Question
MATRUSRI
ENGINEERING COLLEGE
54. Short answer questions
Questions & Answers
MATRUSRI
ENGINEERING COLLEGE
S.NO QUESTION
Blooms
Taxonomy
Level
Course
Outcome
1. Classify the different noises in communication system. CO5
2 Define the noise figure and noise temperature. CO5
3. What is meant by Pre-emphasis and De-emphasis? CO5
4. Explain thermal noise and Shot noise? CO5
5. Explain Equivalent noise temperature in cascaded stages? CO5
55. Long answer questions
Questions & Answers
MATRUSRI
ENGINEERING COLLEGE
S.NO QUESTION
Blooms
Taxonomy
Level
Course
Outcome
1. Define the Terms:
(a) Thermal Noise (b) Shot noise (c) Noise temperature (d) Noise
Figure CO5
2. Derive the figure of merit Expressions for AM, CO5
3. Derive the figure of merit Expressions for DSBSC and SSBSC CO5
4. Derive the expression for figure of merit of FM system. CO5
5. A mixer stage has a noise figure of 25 dB and a stage before it is an
amplifier with a noise figure of 7 dB and an available power gain of
15 db. Find out the overall noise figure referred to input.
CO5