This document provides an overview of digital communication and covers several topics:
- It describes different types of transmission media including guided media like twisted pair cable, coaxial cable, and fiber optic cable. It also covers unguided or wireless media.
- It discusses characteristics of different transmission media and how signals are transmitted through them. This includes concepts like attenuation, distortion, and noise.
- It defines key terms used to measure signal quality like decibels and signal-to-noise ratio.
An Overview of Digital Communication and TransmissionDon Norwood
The document provides an overview of digital communication and transmission systems. It describes the key components of transmitters and receivers, including encoders, modulators, RF sections, and antennas. It also discusses baseband systems, sampling processes, quantization, pulse amplitude modulation (PAM), and non-uniform quantization techniques like μ-law and A-law compression used for voice communication. Aliasing is described as high frequencies taking on the identity of lower frequencies in sampled signals, and methods to eliminate it like anti-aliasing filters and increasing the sampling rate are presented.
introdution to analog and digital communicationSugeng Widodo
This document provides a historical overview of developments in analog and digital communications. It discusses technologies like the telegraph, radio, telephone, electronics, television, digital communications, computer networks, satellite communications, and optical communications. It also describes applications of communications technologies like broadcasting and point-to-point links. Finally, it outlines primary resources for communication systems including transmitted power and channel bandwidth.
The Nyquist formula states that the maximum data rate supported by a bandwidth B is 2B bits per second. Doubling the bandwidth doubles the maximum data rate. Signals with more than two levels can represent more data per signal, with the formula becoming C = 2B log2M, where M is the number of signal levels. Shannon's channel capacity theorem defines the maximum reliable transmission rate C for a bandwidth B channel as C = B log2(1 + S/N), where S is the signal power and N is the noise power.
Analog signals are continuous waves that vary smoothly over time and can have an infinite number of values, while digital signals are discrete and can have only a limited set of values, such as 1 and 0. Analog signals are typically represented by sine waves, while digital signals are represented by square waves. While analog signals are best for audio and video transmission, digital signals are better suited for digital data transmission and provide benefits such as easier compression, encryption, and error detection.
The document discusses key concepts in data transmission including:
1) Transmission occurs over guided or unguided media between a transmitter and receiver.
2) Signals can be analyzed in the frequency domain and have properties like frequency, spectrum, and bandwidth.
3) Both analog and digital signals are used to represent data for transmission.
This document provides an overview of key concepts about data, signals, and their transmission. It discusses:
- The difference between data and signals, and advantages of digital over analog.
- The three components of signals: amplitude, frequency, and phase.
- How signal strength decreases over transmission due to attenuation.
- The four combinations of transmitting data and signals: analog data with analog signals, digital data with digital signals, digital data with analog signals, and analog data with digital signals.
- Several digital encoding schemes for transmitting digital data with digital signals, including NRZ-L, NRZI, Manchester, and Differential Manchester.
This document discusses Integrated Services Digital Network (ISDN) and related concepts. It can be summarized as follows:
ISDN is a set of protocols that combines digital telephony and data services over existing copper telephone lines. It allows transmission of voice, data, text, graphics and video. ISDN services include bearer services to transfer information, teleservices that can process content, and supplementary services with extra functionality. Multiplexing allows multiple signals to be transmitted simultaneously over a single channel by allocating unique time slots or frequencies to each signal.
The Presentation is as per the syllabus of the subject ”Digital Communication” of B.E. VIth Semester of Sant Gadge Baba Amravati University, Maharashtra, India
Contents are
Digital Communication System
Line Coding
Scrambling
An Overview of Digital Communication and TransmissionDon Norwood
The document provides an overview of digital communication and transmission systems. It describes the key components of transmitters and receivers, including encoders, modulators, RF sections, and antennas. It also discusses baseband systems, sampling processes, quantization, pulse amplitude modulation (PAM), and non-uniform quantization techniques like μ-law and A-law compression used for voice communication. Aliasing is described as high frequencies taking on the identity of lower frequencies in sampled signals, and methods to eliminate it like anti-aliasing filters and increasing the sampling rate are presented.
introdution to analog and digital communicationSugeng Widodo
This document provides a historical overview of developments in analog and digital communications. It discusses technologies like the telegraph, radio, telephone, electronics, television, digital communications, computer networks, satellite communications, and optical communications. It also describes applications of communications technologies like broadcasting and point-to-point links. Finally, it outlines primary resources for communication systems including transmitted power and channel bandwidth.
The Nyquist formula states that the maximum data rate supported by a bandwidth B is 2B bits per second. Doubling the bandwidth doubles the maximum data rate. Signals with more than two levels can represent more data per signal, with the formula becoming C = 2B log2M, where M is the number of signal levels. Shannon's channel capacity theorem defines the maximum reliable transmission rate C for a bandwidth B channel as C = B log2(1 + S/N), where S is the signal power and N is the noise power.
Analog signals are continuous waves that vary smoothly over time and can have an infinite number of values, while digital signals are discrete and can have only a limited set of values, such as 1 and 0. Analog signals are typically represented by sine waves, while digital signals are represented by square waves. While analog signals are best for audio and video transmission, digital signals are better suited for digital data transmission and provide benefits such as easier compression, encryption, and error detection.
The document discusses key concepts in data transmission including:
1) Transmission occurs over guided or unguided media between a transmitter and receiver.
2) Signals can be analyzed in the frequency domain and have properties like frequency, spectrum, and bandwidth.
3) Both analog and digital signals are used to represent data for transmission.
This document provides an overview of key concepts about data, signals, and their transmission. It discusses:
- The difference between data and signals, and advantages of digital over analog.
- The three components of signals: amplitude, frequency, and phase.
- How signal strength decreases over transmission due to attenuation.
- The four combinations of transmitting data and signals: analog data with analog signals, digital data with digital signals, digital data with analog signals, and analog data with digital signals.
- Several digital encoding schemes for transmitting digital data with digital signals, including NRZ-L, NRZI, Manchester, and Differential Manchester.
This document discusses Integrated Services Digital Network (ISDN) and related concepts. It can be summarized as follows:
ISDN is a set of protocols that combines digital telephony and data services over existing copper telephone lines. It allows transmission of voice, data, text, graphics and video. ISDN services include bearer services to transfer information, teleservices that can process content, and supplementary services with extra functionality. Multiplexing allows multiple signals to be transmitted simultaneously over a single channel by allocating unique time slots or frequencies to each signal.
The Presentation is as per the syllabus of the subject ”Digital Communication” of B.E. VIth Semester of Sant Gadge Baba Amravati University, Maharashtra, India
Contents are
Digital Communication System
Line Coding
Scrambling
This document provides an introduction and overview of digital communications. It outlines the key elements of a digital communication system including the information source, source encoder, channel encoder, digital modulator, communication channel, digital demodulator, channel decoder, and source decoder. It describes common communication channels such as wireline channels using twisted pair and coaxial cable, fiber optic channels, wireless electromagnetic channels for ground wave, sky wave and line of sight propagation, and underwater acoustic channels. It also discusses mathematical models for communication channels, including the additive noise channel, linear filter channel, and linear time variant filter channel.
The document discusses various communication channels and transmission mediums. It describes wired mediums like two-wire open lines, coaxial cable, and twisted pair lines. It also describes wireless transmission methods like microwave communication, radio, and satellite communication. For each medium, it provides details on bandwidth capacity, common types used, and advantages and disadvantages. The document also discusses channel capacity concepts like Nyquist rate and Shannon-Hartley theorem, and how noise affects channel capacity and data rates.
Chapter 6 - Digital Data Communication Techniques 9eadpeer
Digital data communication techniques use asynchronous or synchronous transmission. Asynchronous transmission sends data one character at a time, while synchronous transmission sends data in blocks without start/stop codes. Error detection codes like parity and CRC are added to detect errors, while error correction codes can correct errors by adding redundancy. Line configurations consider topology (star, bus, etc.) and duplex mode (half duplex uses one path while full duplex uses two simultaneous paths).
This document discusses key concepts in data transmission including:
1) Data transmission can occur over guided mediums like cables or unguided wireless mediums like air, and can be point-to-point, multi-point, simplex, half-duplex, or full-duplex.
2) Analog signals vary continuously over time while digital signals maintain constant levels that change abruptly, and periodic signals have a repeated pattern while aperiodic signals do not.
3) Factors that characterize signals include amplitude, frequency, period, phase, and wavelength. Signals can be analyzed in the frequency domain and represented by their frequency domain functions.
4) Digital data transmission has advantages over analog in being less susceptible
This document provides an overview of digital communications and data transmission. It discusses key concepts such as analog to digital conversion (A/D), source coding, channel encoding, and modulation techniques.
The document begins with defining communication as the reliable transfer of data such as voice, video or codes from one point to another. It then outlines the basic components of a communication system including the information source, transmitter, channel, receiver and information sink.
It further explains the processes of analog to digital conversion including sampling, quantization and coding. It discusses how source coding aims to represent transmitted data more efficiently by removing redundant information. Finally, it provides an introduction to channel encoding which aims to control noise and detect/correct errors, as
This document discusses concepts related to data transmission including terminology, transmission media, signal types, bandwidth, impairments and more. It defines terms like simplex, duplex, guided vs unguided media, analog vs digital signals. It describes properties of periodic signals like sine waves and discusses how signals can be represented in both the time and frequency domains. It also summarizes common transmission impairments like attenuation, delay distortion and noise.
This document discusses key concepts in digital communication including:
1) Sampling of analog signals is required to convert them to digital form, and the sampling frequency must be at least twice the bandwidth to avoid aliasing.
2) Quantization maps sampled analog values to digital codes, while pulse code modulation (PCM) combines sampling and quantization.
3) Digital communication has advantages over analog like better noise immunity and use of error detection/correction.
Effective bandwidth refers to the bandwidth of an input signal that can be transmitted without distortion through a system. If the input signal bandwidth is larger than the system bandwidth, the output will be distorted. The signal and system bandwidths should match. Transmission impairments like attenuation, delay distortion, and noise can distort signals and introduce errors. Different types of cables like twisted pair, coaxial, and optical fiber have different characteristics for digital data transmission.
Wireless Communication and Networking by WilliamStallings Chap2Senthil Kanth
Hai I'm Senthilkanth, doing MCA in Mepco Schlenk Engineering College..
The following presentation covers topic called Wireless Communication and Networking
by WilliamStallings for BSc CS, BCA, MSc CS, MCA, ME students.Make use of it.
Wireless Communication and Networking
by WilliamStallings Chapter : 2Transmission Fundamentals
Chapter 2
Electromagnetic Signal
Function of time
Can also be expressed as a function of frequency
Signal consists of components of different frequencies
Time-Domain Concepts
Analog signal - signal intensity varies in a smooth fashion over time
No breaks or discontinuities in the signal
Digital signal - signal intensity maintains a constant level for some period of time and then changes to another constant level
Periodic signal - analog or digital signal pattern that repeats over time
s(t +T ) = s(t ) -¥< t < +¥
where T is the period of the signal
Time-Domain Concepts
Aperiodic signal - analog or digital signal pattern that doesn't repeat over time
Peak amplitude (A) - maximum value or strength of the signal over time; typically measured in volts
Frequency (f )
Rate, in cycles per second, or Hertz (Hz) at which the signal repeats
Time-Domain Concepts
Period (T ) - amount of time it takes for one repetition of the signal
T = 1/f
Phase () - measure of the relative position in time within a single period of a signal
Wavelength () - distance occupied by a single cycle of the signal
Or, the distance between two points of corresponding phase of two consecutive cycles
Sine Wave Parameters
General sine wave
s(t ) = A sin(2ft + )
Figure 2.3 shows the effect of varying each of the three parameters
(a) A = 1, f = 1 Hz, = 0; thus T = 1s
(b) Reduced peak amplitude; A=0.5
(c) Increased frequency; f = 2, thus T = ½
(d) Phase shift; = /4 radians (45 degrees)
note: 2 radians = 360° = 1 period
Sine Wave Parameters
Time vs. Distance
When the horizontal axis is time, as in Figure 2.3, graphs display the value of a signal at a given point in space as a function of time
With the horizontal axis in space, graphs display the value of a signal at a given point in time as a function of distance
At a particular instant of time, the intensity of the signal varies as a function of distance from the source
Frequency-Domain Concepts
Fundamental frequency - when all frequency components of a signal are integer multiples of one frequency, it’s referred to as the fundamental frequency
Spectrum - range of frequencies that a signal contains
Absolute bandwidth - width of the spectrum of a signal
Effective bandwidth (or just bandwidth) - narrow band of frequencies that most of the signal’s energy is contained in
Frequency-Domain Concepts
Any electromagnetic signal can be shown to consist of a collection of periodic analog signals (sine waves) at different amplitudes, frequencies, and phases
The period of the total signal is equal to the period of the fundamenta
The document introduces some key concepts in data communication, including:
1) Different types of transmission media such as guided (e.g. fiber optic cable) and unguided (e.g. wireless).
2) Analog and digital signals and how analog data can be transmitted using either type of signal.
3) Factors that can impair transmission such as attenuation, delay distortion, and different types of noise. The Nyquist bandwidth and Shannon capacity formulas for calculating maximum data rates are also covered.
This document discusses key concepts in data transmission including:
1) Data transmission involves transmitting data between a transmitter and receiver via some medium, which can be guided (e.g. cable) or unguided/wireless (e.g. air).
2) Transmission can be direct point-to-point, multi-point involving more than two devices, or simplex, half-duplex, or full-duplex depending on direction of communication.
3) Digital signals maintain constant levels that change abruptly, while analog signals vary smoothly over time. Periodic signals have a repeated pattern while aperiodic signals do not.
4) Transmission is impaired by attenuation, delay distortion, noise,
This document provides an outline for a course on communication systems. It covers several key topics:
1) The different types of modulation techniques used in analog and digital communication systems including amplitude, frequency, phase, and pulse modulation.
2) The basic components and functioning of a communication system including information sources, encoding, transmission over a channel, reception and decoding.
3) Characteristics of communication channels such as bandwidth, transmitted power, and how these resources are used efficiently.
4) Differences between analog and digital communication systems and some advantages of digital systems.
This document contains notes from a chapter on transmission fundamentals from a textbook on wireless mobile computer networks. It discusses topics such as electromagnetic signals, time-domain concepts, frequency-domain concepts, analog vs digital signals and data, transmission media types, and multiplexing techniques. Specifically, it provides details on sine wave parameters, bandwidth, signal-to-noise ratio, Shannon capacity formula, classifications of transmission media including guided, unguided, radio frequency and microwave ranges, and examples of multiplexing including frequency-division and time-division.
Mathematical model for communication channelssafeerakd
This document discusses mathematical models for communication channels. It begins by showing a block diagram of a basic digital communication system and defines the key components. It then discusses different types of communication channels and mediums that can be used to transmit signals, including wires, wireless spectra, and optical fibers. The rest of the document discusses several common mathematical models used to represent communication channels, including additive noise channels, linear filter channels, and linear time-variant filter channels. It also discusses parameters that characterize channels and limits on data transmission rates. Finally, it covers optimum receivers for signals corrupted by additive white Gaussian noise.
The document discusses the Public Switched Telephone Network (PSTN) architecture and components. It describes how PSTN uses digital trunks between central office switches and analog lines from phones to the central office. It also discusses digitization of voice signals, the major components of PSTN including local loops, trunks, and switching offices.
The document provides an overview of telecommunications networks and technologies. It discusses components like customer premises equipment, switches, links/trunks. It describes different types of switches, signaling protocols, and access technologies like ISDN, DSL. It also covers transmission standards, intelligent networks, multiple access technologies, and future trends in telecom.
Upon completion of this chapter, students will be able to:
- Understand the key elements of a communication system including information sources, transmitters, transmission mediums, receivers, and destination equipment.
- Comprehend core concepts such as signals, modulation, noise, interference, and frequency spectrums.
- Learn about various communication system types including radio, broadcasting, and computer networks.
This document defines telecommunications terms beginning with A. Key terms include:
- A-law algorithm, a standard compression algorithm used in European digital communications to optimize the dynamic range of analog signals for digitizing.
- Abbreviated dialing, a telephone service that allows users to dial fewer digits to access frequently called numbers.
- Absolute gain, the ratio of output to input signal levels of a device under specified conditions, usually expressed in decibels.
- Absorption, the conversion of transmitted energy into another form like heat during signal propagation, which causes attenuation.
The document discusses computer communication architecture and the OSI and TCP/IP models. It provides details on each layer of the OSI model, including the layer number, name, function, and PDU. It also discusses data encapsulation, analogies to explain how data moves through the OSI layers, and compares the OSI and TCP/IP models. The TCP/IP model has fewer layers and is focused on interoperability rather than standards.
The document provides an overview of wireless networks and wireless communication technologies. It discusses the key elements of a wireless network including wireless hosts, base stations, wireless links, infrastructure and ad hoc modes. It also covers wireless link characteristics such as signal attenuation, interference and multipath propagation. Finally, it introduces common wireless network standards and protocols including IEEE 802.11 wireless LANs, wireless network characteristics such as the hidden terminal problem, and wireless multiple access protocols.
This document provides an introduction and overview of digital communications. It outlines the key elements of a digital communication system including the information source, source encoder, channel encoder, digital modulator, communication channel, digital demodulator, channel decoder, and source decoder. It describes common communication channels such as wireline channels using twisted pair and coaxial cable, fiber optic channels, wireless electromagnetic channels for ground wave, sky wave and line of sight propagation, and underwater acoustic channels. It also discusses mathematical models for communication channels, including the additive noise channel, linear filter channel, and linear time variant filter channel.
The document discusses various communication channels and transmission mediums. It describes wired mediums like two-wire open lines, coaxial cable, and twisted pair lines. It also describes wireless transmission methods like microwave communication, radio, and satellite communication. For each medium, it provides details on bandwidth capacity, common types used, and advantages and disadvantages. The document also discusses channel capacity concepts like Nyquist rate and Shannon-Hartley theorem, and how noise affects channel capacity and data rates.
Chapter 6 - Digital Data Communication Techniques 9eadpeer
Digital data communication techniques use asynchronous or synchronous transmission. Asynchronous transmission sends data one character at a time, while synchronous transmission sends data in blocks without start/stop codes. Error detection codes like parity and CRC are added to detect errors, while error correction codes can correct errors by adding redundancy. Line configurations consider topology (star, bus, etc.) and duplex mode (half duplex uses one path while full duplex uses two simultaneous paths).
This document discusses key concepts in data transmission including:
1) Data transmission can occur over guided mediums like cables or unguided wireless mediums like air, and can be point-to-point, multi-point, simplex, half-duplex, or full-duplex.
2) Analog signals vary continuously over time while digital signals maintain constant levels that change abruptly, and periodic signals have a repeated pattern while aperiodic signals do not.
3) Factors that characterize signals include amplitude, frequency, period, phase, and wavelength. Signals can be analyzed in the frequency domain and represented by their frequency domain functions.
4) Digital data transmission has advantages over analog in being less susceptible
This document provides an overview of digital communications and data transmission. It discusses key concepts such as analog to digital conversion (A/D), source coding, channel encoding, and modulation techniques.
The document begins with defining communication as the reliable transfer of data such as voice, video or codes from one point to another. It then outlines the basic components of a communication system including the information source, transmitter, channel, receiver and information sink.
It further explains the processes of analog to digital conversion including sampling, quantization and coding. It discusses how source coding aims to represent transmitted data more efficiently by removing redundant information. Finally, it provides an introduction to channel encoding which aims to control noise and detect/correct errors, as
This document discusses concepts related to data transmission including terminology, transmission media, signal types, bandwidth, impairments and more. It defines terms like simplex, duplex, guided vs unguided media, analog vs digital signals. It describes properties of periodic signals like sine waves and discusses how signals can be represented in both the time and frequency domains. It also summarizes common transmission impairments like attenuation, delay distortion and noise.
This document discusses key concepts in digital communication including:
1) Sampling of analog signals is required to convert them to digital form, and the sampling frequency must be at least twice the bandwidth to avoid aliasing.
2) Quantization maps sampled analog values to digital codes, while pulse code modulation (PCM) combines sampling and quantization.
3) Digital communication has advantages over analog like better noise immunity and use of error detection/correction.
Effective bandwidth refers to the bandwidth of an input signal that can be transmitted without distortion through a system. If the input signal bandwidth is larger than the system bandwidth, the output will be distorted. The signal and system bandwidths should match. Transmission impairments like attenuation, delay distortion, and noise can distort signals and introduce errors. Different types of cables like twisted pair, coaxial, and optical fiber have different characteristics for digital data transmission.
Wireless Communication and Networking by WilliamStallings Chap2Senthil Kanth
Hai I'm Senthilkanth, doing MCA in Mepco Schlenk Engineering College..
The following presentation covers topic called Wireless Communication and Networking
by WilliamStallings for BSc CS, BCA, MSc CS, MCA, ME students.Make use of it.
Wireless Communication and Networking
by WilliamStallings Chapter : 2Transmission Fundamentals
Chapter 2
Electromagnetic Signal
Function of time
Can also be expressed as a function of frequency
Signal consists of components of different frequencies
Time-Domain Concepts
Analog signal - signal intensity varies in a smooth fashion over time
No breaks or discontinuities in the signal
Digital signal - signal intensity maintains a constant level for some period of time and then changes to another constant level
Periodic signal - analog or digital signal pattern that repeats over time
s(t +T ) = s(t ) -¥< t < +¥
where T is the period of the signal
Time-Domain Concepts
Aperiodic signal - analog or digital signal pattern that doesn't repeat over time
Peak amplitude (A) - maximum value or strength of the signal over time; typically measured in volts
Frequency (f )
Rate, in cycles per second, or Hertz (Hz) at which the signal repeats
Time-Domain Concepts
Period (T ) - amount of time it takes for one repetition of the signal
T = 1/f
Phase () - measure of the relative position in time within a single period of a signal
Wavelength () - distance occupied by a single cycle of the signal
Or, the distance between two points of corresponding phase of two consecutive cycles
Sine Wave Parameters
General sine wave
s(t ) = A sin(2ft + )
Figure 2.3 shows the effect of varying each of the three parameters
(a) A = 1, f = 1 Hz, = 0; thus T = 1s
(b) Reduced peak amplitude; A=0.5
(c) Increased frequency; f = 2, thus T = ½
(d) Phase shift; = /4 radians (45 degrees)
note: 2 radians = 360° = 1 period
Sine Wave Parameters
Time vs. Distance
When the horizontal axis is time, as in Figure 2.3, graphs display the value of a signal at a given point in space as a function of time
With the horizontal axis in space, graphs display the value of a signal at a given point in time as a function of distance
At a particular instant of time, the intensity of the signal varies as a function of distance from the source
Frequency-Domain Concepts
Fundamental frequency - when all frequency components of a signal are integer multiples of one frequency, it’s referred to as the fundamental frequency
Spectrum - range of frequencies that a signal contains
Absolute bandwidth - width of the spectrum of a signal
Effective bandwidth (or just bandwidth) - narrow band of frequencies that most of the signal’s energy is contained in
Frequency-Domain Concepts
Any electromagnetic signal can be shown to consist of a collection of periodic analog signals (sine waves) at different amplitudes, frequencies, and phases
The period of the total signal is equal to the period of the fundamenta
The document introduces some key concepts in data communication, including:
1) Different types of transmission media such as guided (e.g. fiber optic cable) and unguided (e.g. wireless).
2) Analog and digital signals and how analog data can be transmitted using either type of signal.
3) Factors that can impair transmission such as attenuation, delay distortion, and different types of noise. The Nyquist bandwidth and Shannon capacity formulas for calculating maximum data rates are also covered.
This document discusses key concepts in data transmission including:
1) Data transmission involves transmitting data between a transmitter and receiver via some medium, which can be guided (e.g. cable) or unguided/wireless (e.g. air).
2) Transmission can be direct point-to-point, multi-point involving more than two devices, or simplex, half-duplex, or full-duplex depending on direction of communication.
3) Digital signals maintain constant levels that change abruptly, while analog signals vary smoothly over time. Periodic signals have a repeated pattern while aperiodic signals do not.
4) Transmission is impaired by attenuation, delay distortion, noise,
This document provides an outline for a course on communication systems. It covers several key topics:
1) The different types of modulation techniques used in analog and digital communication systems including amplitude, frequency, phase, and pulse modulation.
2) The basic components and functioning of a communication system including information sources, encoding, transmission over a channel, reception and decoding.
3) Characteristics of communication channels such as bandwidth, transmitted power, and how these resources are used efficiently.
4) Differences between analog and digital communication systems and some advantages of digital systems.
This document contains notes from a chapter on transmission fundamentals from a textbook on wireless mobile computer networks. It discusses topics such as electromagnetic signals, time-domain concepts, frequency-domain concepts, analog vs digital signals and data, transmission media types, and multiplexing techniques. Specifically, it provides details on sine wave parameters, bandwidth, signal-to-noise ratio, Shannon capacity formula, classifications of transmission media including guided, unguided, radio frequency and microwave ranges, and examples of multiplexing including frequency-division and time-division.
Mathematical model for communication channelssafeerakd
This document discusses mathematical models for communication channels. It begins by showing a block diagram of a basic digital communication system and defines the key components. It then discusses different types of communication channels and mediums that can be used to transmit signals, including wires, wireless spectra, and optical fibers. The rest of the document discusses several common mathematical models used to represent communication channels, including additive noise channels, linear filter channels, and linear time-variant filter channels. It also discusses parameters that characterize channels and limits on data transmission rates. Finally, it covers optimum receivers for signals corrupted by additive white Gaussian noise.
The document discusses the Public Switched Telephone Network (PSTN) architecture and components. It describes how PSTN uses digital trunks between central office switches and analog lines from phones to the central office. It also discusses digitization of voice signals, the major components of PSTN including local loops, trunks, and switching offices.
The document provides an overview of telecommunications networks and technologies. It discusses components like customer premises equipment, switches, links/trunks. It describes different types of switches, signaling protocols, and access technologies like ISDN, DSL. It also covers transmission standards, intelligent networks, multiple access technologies, and future trends in telecom.
Upon completion of this chapter, students will be able to:
- Understand the key elements of a communication system including information sources, transmitters, transmission mediums, receivers, and destination equipment.
- Comprehend core concepts such as signals, modulation, noise, interference, and frequency spectrums.
- Learn about various communication system types including radio, broadcasting, and computer networks.
This document defines telecommunications terms beginning with A. Key terms include:
- A-law algorithm, a standard compression algorithm used in European digital communications to optimize the dynamic range of analog signals for digitizing.
- Abbreviated dialing, a telephone service that allows users to dial fewer digits to access frequently called numbers.
- Absolute gain, the ratio of output to input signal levels of a device under specified conditions, usually expressed in decibels.
- Absorption, the conversion of transmitted energy into another form like heat during signal propagation, which causes attenuation.
The document discusses computer communication architecture and the OSI and TCP/IP models. It provides details on each layer of the OSI model, including the layer number, name, function, and PDU. It also discusses data encapsulation, analogies to explain how data moves through the OSI layers, and compares the OSI and TCP/IP models. The TCP/IP model has fewer layers and is focused on interoperability rather than standards.
The document provides an overview of wireless networks and wireless communication technologies. It discusses the key elements of a wireless network including wireless hosts, base stations, wireless links, infrastructure and ad hoc modes. It also covers wireless link characteristics such as signal attenuation, interference and multipath propagation. Finally, it introduces common wireless network standards and protocols including IEEE 802.11 wireless LANs, wireless network characteristics such as the hidden terminal problem, and wireless multiple access protocols.
The data link layer provides services to the network layer such as framing data and applying error detection methods like parity checks, checksums and cyclic redundancy checks to frames. Common data link protocols are used at this layer.
The document discusses several networking concepts:
- Classless Inter-Domain Routing (CIDR) allows ISPs to allocate blocks of IP addresses to organizations in a more efficient manner than previous methods.
- Network Address Translation (NAT) allows a local network to use private IP address ranges behind a NAT-enabled router that maps the private addresses to a single public IP address for communication with external networks.
- Subnetting and Variable Length Subnet Masking (VLSM) allow networks to be divided into subnets to better utilize limited IP address blocks and assign addresses based on subnet needs.
- Supernetting combines multiple classful network blocks into larger supernets to more efficiently use address space.
The document describes routing algorithms used in computer networks. It discusses two main types of routing algorithms: link-state algorithms and distance-vector algorithms. Link-state algorithms use a complete map of the entire network topology to calculate the shortest paths between all nodes, while distance-vector algorithms use an iterative process where each router shares routing information with neighbors to determine the shortest paths. The document then provides examples of how Dijkstra's algorithm, a link-state algorithm, and the Bellman-Ford distance-vector algorithm work to calculate the optimal paths through a sample network.
Signals traveling through transmission media experience impairment due to attenuation, distortion, and noise. Attenuation refers to loss of signal strength over distance. Distortion occurs when different frequency components of a signal arrive at different times due to traveling at different speeds. Noise refers to unwanted signals added from various sources like thermal noise, crosstalk, and impulse noise. Engineers measure signal impairment using metrics like decibels and signal-to-noise ratio.
This document discusses various types of transmission impairments including attenuation, distortion, and noise. Attenuation is the reduction of signal strength during transmission, while distortion alters the original signal shape. There are different types of distortion such as amplitude, delay, and frequency distortion. Noise refers to random electrical signals that interfere with reception, and can come from internal or external sources. Signal-to-noise ratio and noise figure are discussed as ways to measure noise levels relative to signals.
Network transmission impairments can degrade or corrupt signals and introduce bit errors. Attenuation causes signals to weaken over distance depending on the transmission medium. Delay distortion occurs for guided media where propagation speed varies with frequency. Noise such as thermal, intermodulation, crosstalk, and impulse noise from external sources can also be introduced that interferes with the original signal.
With any communications system, it must be recognized that the received signal may differ from the transmitted signal due to various transmission impairments.
This document discusses different types of transmission media used for data communication. It describes guided media such as twisted pair cables, coaxial cables, and fiber optic cables. It also covers unguided or wireless media such as radio waves, microwaves, and infrared. For each medium, it provides details on their characteristics, applications, advantages and disadvantages. The document aims to classify and explain the basic concepts of different transmission media and their use in data communication networks.
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 document discusses concepts related to transmission impairments and channel capacity. It begins by defining different types of communication including simplex, half-duplex, and full-duplex. It then discusses sources of transmission impairment including attenuation, distortion, noise and how they degrade signals. It defines signal-to-noise ratio and how it is used to measure quality. Bandwidth and channel capacity are also mentioned. Examples are provided to illustrate key concepts like decibel calculation and analyzing problems related to signal attenuation and distortion.
OSI model - physical layer,Transmission medium, switching mechanisms, multipl...sandhyakiran10
The physical layer is responsible for transmitting signals over a transmission medium. It handles functions like signal encoding/decoding, synchronization, and data rates. Transmission is impaired by attenuation, distortion, and noise as signals propagate. Attenuation reduces signal strength, distortion changes signal shape, and noise corrupts signals. Theoretical maximum data rates are given by Nyquist's formula for noiseless channels and Shannon's formula for noisy channels, which depends on bandwidth and signal-to-noise ratio. Higher data rates require wider bandwidths, more signal levels, or less noise.
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.
This document discusses transmission impairment, which refers to degradation of signals as they travel through transmission media. There are three main causes of transmission impairment: 1) attenuation, which is the loss of signal energy as it passes through a medium, 2) distortion, which is a change in the signal's form or shape, such as different frequency components arriving at different times, and 3) noise, which adds unwanted signals from sources like thermal effects, interference, or crosstalk between wires. Attenuation is measured in decibels and can be compensated for using amplifiers, while signal to noise ratio (SNR) measures the quality of a transmission system by comparing the signal strength to the noise power.
This document discusses electronic communication and microwave systems. It covers topics like introduction to communication systems, transmitters, channels, receivers, transceivers, modulation, multiplexing, bandwidth, gain, attenuation, and decibels. The document also lists materials, class rules, assessments, and provides an introduction to electronic communication including its history and basic components like transmitters, channels, and receivers.
This document provides an overview of optical fiber communications. It discusses the history of fiber optics, including how fiber transmission improved on electrical transmission. The key advantages of optical fibers are described. The electromagnetic spectrum is shown, focusing on the optical spectral bands used for fiber communications. The document outlines the windows and spectral bands designated for fiber optic links. It also discusses network information rates and standards for optical fiber communications.
This document summarizes key topics in optical communication systems including:
- Common wavelength bands used in optical fibers ranging from O band to U band.
- The two main types of modulation used - digital and analog.
- Common sources, detectors, and other components used in optical systems like lasers, photodiodes, and repeaters.
- Digital transmission standards like SONET which allows for flexibility in adding new services.
- How optical power levels are computed using decibels to calculate loss over fiber optic links.
This document discusses transmission impairment in data communications and networking. It describes three main causes of impairment: attenuation, distortion, and noise. Attenuation is the loss of signal strength over distance due to resistance in the transmission medium. Distortion occurs when different signal frequencies arrive at different times due to differences in propagation speed. Noise corrupts signals from sources like thermal motion and electromagnetic interference. The document also covers decibel measurement of signal loss/gain, signal-to-noise ratio, Nyquist's theorem on maximum data rate for noiseless channels, Shannon's capacity theorem for noisy channels, and the difference between bandwidth and throughput.
Transmission media can be guided or unguided. Guided media includes twisted pair cable, coaxial cable, and fibre optic cable. Twisted pair cable comes in shielded and unshielded variants and is commonly used for telephone lines and low-speed networks. Coaxial cable transmits signals with less interference but is more expensive and difficult to install than twisted pair. Fibre optic cable can transmit data at very high speeds but requires more specialized equipment. Unguided or wireless transmission sends signals through radio waves, microwaves, or infrared using antennas for propagation through free space.
Analog modulation is used to transmit analog signals over communication channels. It involves varying characteristics of a high-frequency carrier signal using an analog baseband signal. There are three main types of analog modulation: amplitude modulation, frequency modulation, and phase modulation. Modulation is necessary to reduce antenna size, allow for multiplexing of signals, avoid equipment limitations, and make the signal less susceptible to noise interference.
Transmission media are located below the physical layer and are used to transmit signals representing data. There are two main types of transmission media: guided media (wired), which provide a conduit for transmission, and unguided media (wireless), which transmit via electromagnetic waves without a physical pathway. Common guided media include twisted-pair cable, coaxial cable, and fiber-optic cable. Unguided media include radio waves, microwaves, and infrared. Each type of transmission media has different characteristics that determine its suitable uses.
6G wireless communications will be immersed in the future with different applications. It
is expected to support all IoT services and satellite communications, and it is expected to support
artificial intelligence (AI) and machine learning (ML). The THz frequency band has a vital role in 6G
communication. In this study, a new graphene plasmonic two-port Terahertz (THz) MIMO antenna
is analyzed by the characteristic mode theory (CMA), which gives a better insight into the physical
behavior of the MIMO configurations. The proposed MIMO antenna is compact and designed on a
Teflon substrate of 130 85 m2. The antenna provides a wide impedance bandwidth of 0.6 THz
(3.2–3.8 THz). The CMA is applied to clarify the position at which the mutual coupling gives a
maximum concentrated current distribution. It is mainly used to reveal the preferable MIMO antenna
configuration by the usage of the model significant and model current distribution property. To
reduce the mutual coupling between the radiating elements, a complementary dumbbell-structure
Metamaterial (MTM) unit cell is etched in the ground plane to block the coupling mode without any
affection on the dominant mode. The preferred MIMO configuration gives high isolation of 55 dB
between the radiating patches. The fundamental characteristics have been discussed in detail. The
proposed MIMO design offers several attractive features such as large bandwidth of 0.6 THz, low
envelope correlation coefficient (ECC) of 0.000168, compact size, stable radiation, high gain of 7.23 dB,
and low channel capacity loss (CCL) of 0.006. The proposed MIMO design is suitable for different
applications in the THz band according to the high-performance parameters such as biomedical
applications, security scanning, sensing, IoT, and 6G high-speed wireless communication systems.
Communication is the process of exchanging information between two points using a transmission medium. The document discusses various components of a basic communication system including the transmitter, receiver, and channel. It also covers different modulation techniques like amplitude modulation and frequency modulation that are used to encode information onto carrier signals for transmission. Wired mediums like twisted pair cables and wireless mediums like radio waves are discussed as potential transmission channels.
Communication is the process of exchanging information between two points using a transmission medium. Wired communication uses physical cables to transmit information while wireless communication transmits information through radio frequencies in the air without cables. A basic communication system includes a transmitter that encodes and transmits a signal, a channel that carries the signal, and a receiver that decodes the signal. Common forms of modulation include amplitude modulation and frequency modulation. Multiplexing techniques like time-division multiplexing and frequency-division multiplexing allow multiple signals to be transmitted simultaneously over the same medium.
Transmission media carry signals from sender to receiver. Guided media use physical paths like twisted pair cable, coaxial cable, and fiber optic cable. Unguided or wireless media transmit signals through the air using radio waves, microwaves, or infrared without a physical path. Guided media are classified based on the material used and include twisted pair, coaxial cable, and fiber optic cable. Each type has different characteristics, applications, advantages, and disadvantages for data transmission.
The document discusses different types of transmission media including guided media like twisted pair cable, coaxial cable, fiber optic cable and unguided media like radio waves, microwaves, and infrared. It provides details on each medium like their construction, applications, advantages and disadvantages. It also discusses concepts like propagation modes, transmission impairment and electromagnetic spectrum used for wireless communication. Satellite communication is discussed along with different types of satellites based on their orbit - geostationary, medium earth orbit and low earth orbit satellites.
This document provides an overview of computer networks and transmission media. It discusses various types of guided media like twisted pair cable, coaxial cable, and fiber optic cable. It also covers unguided or wireless transmission media like radio waves, microwaves, and infrared waves. Key topics include transmission impairments, propagation modes, antennas, and wireless channel characteristics. Multiple choice questions are provided at the end to test understanding of transmission media concepts.
A communications system allows for the transfer of information from an information source to an information sink. It consists of a transmitter that encodes a message from the information source into a transmitted signal, a channel to carry the signal, and a receiver to decode the signal back into a message for the information sink.
The transmitter may perform operations like modulation, amplification, and filtering on the message signal. The channel can be a wireline medium like coaxial cable or a wireless medium like free space. It is subject to degradation from noise, interference and distortion. The receiver performs complementary operations to the transmitter like demodulation, amplification and filtering to recover the original message from the received signal for the information sink.
This document discusses various computer arithmetic operations including addition, subtraction, multiplication, and division for signed magnitude and two's complement data representations. It describes the Booth multiplication algorithm, array multipliers for performing multiplication using combinational circuits, and the division algorithm. It also covers detecting divide overflow conditions.
The document provides an introduction to computer security including:
- The basic components of security such as confidentiality, integrity, and availability.
- Common security threats like snooping, modification, and denial of service attacks.
- Issues with security including operational challenges and human factors.
- An overview of security policies, access control models, and security models like Bell-LaPadula and Biba.
Cookies and sessions allow servers to remember information about users across multiple web pages. Cookies are small files stored on a user's computer that identify users and can store data to be accessed on subsequent page requests. Sessions use cookies to identify users and store temporary data on the server side to be accessed across multiple pages in one application, such as usernames or preferences. Both cookies and sessions must be started before any page output to ensure headers are sent before the page body.
This document discusses different aspects of functions in programming including declaring and calling functions, passing arguments to functions, and returning values from functions. It also covers variable scope. Some key points covered are declaring functions with and without arguments, specifying default values, returning single values or arrays from functions, and understanding variable scope and how it relates to the global and $GLOBALS keywords and array.
This document discusses various aspects of working with web forms in PHP, including:
1) Useful server variables for forms like QUERY_STRING and SERVER_NAME.
2) Accessing form parameters submitted to the server.
3) Processing forms with functions, including validating form data with techniques like checking for required fields and valid email addresses.
4) Displaying default values or error messages for form fields.
5) Stripping HTML tags from form inputs and encoding special characters for safe display.
The document provides examples of implementing each of these techniques.
The document discusses various programming concepts related to decision making and repetition in code including understanding true and false values, using if/elseif/else statements, equality and relational operators, logical operators, and using while and for loops to repeat code. Specific topics covered include evaluating booleans, making single and multi-line if statements, comparing different data types, negation, and printing select menus with loops.
This document discusses working with arrays in PHP. It covers array basics like creating and accessing arrays, looping through arrays with foreach and for loops, modifying arrays by adding/removing elements and sorting arrays. It also discusses multidimensional arrays, how to create them and access elements within them.
This document discusses text and numbers in programming. It covers defining and manipulating text strings using single or double quotes. Escape characters can be used inside strings. Text can be validated and formatted using various string functions like trim(), strlen(), strtoupper(), substr(), and str_replace(). Numbers can be integers or floats. Variables hold data and can be operated on with arithmetic and assignment operators like +, -, *, /, %, and .=. Variables can also be incremented, decremented, and placed inside strings.
This document provides an introduction and overview of PHP for beginners. It discusses PHP's use for building websites, how PHP code is run on web servers and accessed through browsers. It then highlights some key advantages of PHP like being free, cross-platform, and widely used. It demonstrates a basic "Hello World" PHP program and shows how to output HTML forms and formatted numbers. Finally, it outlines some basic rules of PHP programs regarding tags, syntax, whitespace, comments, and case sensitivity.
The document discusses capacity planning for a data warehouse environment. It notes that capacity planning is important given the large volumes of data and processing in a data warehouse. It describes factors that make capacity planning unique for a data warehouse, such as variable workloads and larger data volumes than operational systems. The document provides guidance on estimating disk storage needs, classifying and estimating processing workloads, creating workload profiles, identifying peak capacity needs, and selecting hardware capacity to meet needs.
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Search engines allow users to search the vast collection of documents on the web. They consist of crawlers that fetch web pages, indexers that analyze page content and links, and interfaces that allow users to enter queries. Crawlers add pages to an index by following links, and indexers create inverted indexes to map words to pages. When a query is searched, results are retrieved from the index and ranked based on relevance. PageRank is a key algorithm that ranks pages higher that receive more links from other highly ranked pages. While it effectively searches the large, diverse and dynamic web, search poses challenges in understanding ambiguous queries over an evolving collection.
Web mining involves applying data mining techniques to discover useful information from web data. There are three types of web mining: web content mining analyzes data within web pages, web structure mining examines the hyperlink structure between pages, and web usage mining involves analyzing server logs to discover patterns in user behavior and interactions with websites. Web mining has applications in website design, web traffic analysis, e-commerce personalization, and security/crime investigation.
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Information and Communication Technology in EducationMJDuyan
(𝐓𝐋𝐄 𝟏𝟎𝟎) (𝐋𝐞𝐬𝐬𝐨𝐧 2)-𝐏𝐫𝐞𝐥𝐢𝐦𝐬
𝐄𝐱𝐩𝐥𝐚𝐢𝐧 𝐭𝐡𝐞 𝐈𝐂𝐓 𝐢𝐧 𝐞𝐝𝐮𝐜𝐚𝐭𝐢𝐨𝐧:
Students will be able to explain the role and impact of Information and Communication Technology (ICT) in education. They will understand how ICT tools, such as computers, the internet, and educational software, enhance learning and teaching processes. By exploring various ICT applications, students will recognize how these technologies facilitate access to information, improve communication, support collaboration, and enable personalized learning experiences.
𝐃𝐢𝐬𝐜𝐮𝐬𝐬 𝐭𝐡𝐞 𝐫𝐞𝐥𝐢𝐚𝐛𝐥𝐞 𝐬𝐨𝐮𝐫𝐜𝐞𝐬 𝐨𝐧 𝐭𝐡𝐞 𝐢𝐧𝐭𝐞𝐫𝐧𝐞𝐭:
-Students will be able to discuss what constitutes reliable sources on the internet. They will learn to identify key characteristics of trustworthy information, such as credibility, accuracy, and authority. By examining different types of online sources, students will develop skills to evaluate the reliability of websites and content, ensuring they can distinguish between reputable information and misinformation.
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4. GUIDED MEDIA
Guided media, which are those that provide a conduit
from one device to another, include twisted-pair cable,
coaxial cable, and fiber-optic cable.
22. Advantages of Optical Fiber
Higher bandwidth
Less signal attenuation
Immunity to electromagnetic Interference
Resistance to corrosive materials
Light weight
More immune to tapping
24. UNGUIDED MEDIA: WIRELESS
Unguided media transport electromagnetic waves
without using a physical conductor. This type of
communication is often referred to as wireless
communication.
Radio Waves
Microwaves
Infrared
Topics discussed in this section:
29. Radio waves(3 KHz- 1 GHz) are used for multicast communications, such as radio and
television, and paging systems.
They can penetrate through walls.
Highly regulated.
Use omni directional antennas
Note
31. Microwaves(1-300 GHz) are used for unicast communication such as cellular
telephones, satellite networks,
and wireless LANs.
Higher frequency ranges cannot penetrate walls.
Use directional antennas - point to point line of sight communications.
Note
33. Infrared signals can be used for short-range communication in a closed area using
line-of-sight propagation.
Note
34. TRANSMISSION IMPAIRMENT
Signals travel through transmission media, which are not perfect. The imperfection causes
signal impairment. This means that the signal at the beginning of the medium is not the
same as the signal at the end of the medium. What is sent is not what is received. Three
causes of impairment are attenuation, distortion, and noise.
36. Attenuation
• Means loss of energy -> weaker signal
• When a signal travels through a medium it
loses energy overcoming the resistance of
the medium
• Amplifiers are used to compensate for this
loss of energy by amplifying the signal.
37. Measurement of Attenuation
• To show the loss or gain of energy the unit
“decibel” is used.
dB = 10log10P2/P1
P1 - input signal
P2 - output signal
39. Suppose a signal travels through a transmission medium and its power is reduced to one-
half. This means that P2 is (1/2)P1. Find the attenuation (loss of power)
Example
40. A loss of 3 dB (–3 dB) is equivalent to losing one-half the power.
Solution
:
41. A signal travels through an amplifier, and its power is increased 10 times. This means that
P2 = 10P1 . In this case, the amplification (gain of power) can be calculated as
Example
43. Distortion
• Means that the signal changes its form or shape
• Distortion occurs in composite signals
• Each frequency component has its own
propagation speed traveling through a medium.
• The different components therefore arrive with
different delays at the receiver.
• That means that the signals have different phases
at the receiver than they did at the source.
45. Noise
• There are different types of noise
– Thermal - random noise of electrons in the
wire creates an extra signal
– Induced - from motors and appliances, devices
act are transmitter antenna and medium as
receiving antenna.
– Crosstalk - same as above but between two
wires.
– Impulse - Spikes that result from power lines,
lightning, etc.
47. Signal to Noise Ratio (SNR)
• To measure the quality of a system the SNR
is often used. It indicates the strength of
the signal wrt the noise power in the
system.
• It is the ratio between two powers.
• It is usually given in dB and referred to as
SNRdB.
48. The power of a signal is 10 mW and the power of the noise is 1 μW; what are the values
of SNR and SNRdB ?
Example
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