The document provides an overview of topics covered in Chapter 1 of an introduction to electronic communication textbook. It discusses the significance of human communication, components of communication systems including transmitters, channels, and receivers. It also describes types of electronic communication such as simplex, full duplex, and digital/analog signals. Modulation, multiplexing, and the electromagnetic spectrum are explained. The chapter concludes with an overview of various communication applications and careers in the communication industry.
A communication system is for transmitting and receiving the information that users want to exchange. To make up a communication system, we can adopt the FDMA, TDMA, CDMA, and so on. In this presentation, we introduce a simplified communication blocks with which we can understand a modern system.
A communication system is for transmitting and receiving the information that users want to exchange. To make up a communication system, we can adopt the FDMA, TDMA, CDMA, and so on. In this presentation, we introduce a simplified communication blocks with which we can understand a modern system.
Topics covered in this presentation:
Radio & Microwave Communication.
2. Spectrum Management.
3. Digital Microwave Systems.
4. Fading and measures to counter Fading effect.
5. Digital Microwave link – Performance Objectives.
6. Modulation Methods.
7. A word about BWA
8. Other wireless communication Applications
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
Topics covered in this presentation:
Radio & Microwave Communication.
2. Spectrum Management.
3. Digital Microwave Systems.
4. Fading and measures to counter Fading effect.
5. Digital Microwave link – Performance Objectives.
6. Modulation Methods.
7. A word about BWA
8. Other wireless communication Applications
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
In this chapter we examine the capacity of a single-user wireless channel where transmitter and/or receiver have a single antenna. We will discuss capacity for channels that are both time invariant and time varying. We first look at the well-known formula for capacity of a time-invariant additive white Gaussian noise (AWGN) channel and then consider capacity of time-varying flat fading channels. We will first consider flat fading channel capacity where only the fading distribution is known at the transmitter and receiver. We will also treat capacity of frequency-selective fading channels. For time -invariant frequency-selective channels the capacity is known and is achieved with an optimal power allocation that water-fills over frequency instead of time. We will consider only discrete-time systems in this chapter.
http://www.reinventyourselftogreatness.com
To be able to grow as self development, personal leadership you need to stay away from toxic people that might have limiting beliefs. This presentation is about recognizing toxic traits in some people as warning signs 15 toxic people traits to stay away from
How to Handle Guest with Complaints in HotelHotelCluster
The key to running a successful hotel is customer service. A big part of this is addressing customer complaints and ensuring that these complaints are resolved to the customer’s satisfaction. Successful resolution will have a positive effect on the customer, who will be more conducive to returning to the hotel in the future, as the way the complaint was handled and resolved makes the customer feel special and shows him that the hotel is genuinely interested in keeping its customers happy and satisfied.
2. 3
Topics Covered in Chapter 1
1-1: Significance of Human Communication
1-2: Communication Systems
1-3: Types of Electronic Communication
1-4: Modulation and Multiplexing
3. Topics Covered in Chapter 1
(continued)
1-5: The Electromagnetic Spectrum
1-6: Bandwidth
1-7: A Survey of Communication Applications
1-8: Jobs and Careers in the Communication Industry
4
4. 1-1: Significance of
Human Communication
Communication is the process of exchanging
information.
Main barriers are language and distance.
Contemporary society’s emphasis is now the
accumulation, packaging, and exchange of
information.
5
5. 1-1: Significance of
Human Communication
Methods of communication:
1.Face to face
2.Signals
3.Written word (letters)
4.Electrical innovations:
Telegraph
Telephone
Radio
Television
Internet (computer)
6
6. 7
1-2: Communication Systems
Basic components:
Transmitter
Channel or medium
Receiver
Noise degrades or interferes with transmitted
information.
8. 9
1-2: Communication Systems
Transmitter
The transmitter is a collection of electronic
components and circuits that converts the electrical
signal into a signal suitable for transmission over a
given medium.
Transmitters are made up of oscillators, amplifiers,
tuned circuits and filters, modulators, frequency mixers,
frequency synthesizers, and other circuits.
9. 10
1-2: Communication Systems
Communication Channel
The communication channel is the medium by which
the electronic signal is sent from one place to another.
Types of media include
Electrical conductors
Optical media
Free space
System-specific media (e.g., water is the medium for sonar).
10. 11
1-2: Communication Systems
Receivers
A receiver is a collection of electronic components and
circuits that accepts the transmitted message from the
channel and converts it back into a form understandable
by humans.
Receivers contain amplifiers, oscillators, mixers, tuned
circuits and filters, and a demodulator or detector that
recovers the original intelligence signal from the
modulated carrier.
11. 12
1-2: Communication Systems
Transceivers
A transceiver is an electronic unit that incorporates
circuits that both send and receive signals.
Examples are:
• Telephones
• Fax machines
• Handheld CB radios
• Cell phones
• Computer modems
12. 13
1-2: Communication Systems
Attenuation
Signal attenuation, or degradation, exists in all media
of wireless transmission. It is proportional to the square
of the distance between the transmitter and receiver.
13. 14
1-2: Communication Systems
Noise
Noise is random, undesirable electronic energy that
enters the communication system via the
communicating medium and interferes with the
transmitted message.
14. 1-3: Types of Electronic
Communication
Electronic communications are classified according
to whether they are
1. One-way (simplex) or two-way (full duplex or half
duplex) transmissions
2. Analog or digital signals.
15
15. 1-3: Types of Electronic
Communication
Simplex
The simplest method of electronic communication is
referred to as simplex.
This type of communication is one-way. Examples are:
Radio
TV broadcasting
Beeper (personal receiver)
16
16. 1-3: Types of Electronic
Communication
Full Duplex
Most electronic communication is two-way and is
referred to as duplex.
When people can talk and listen simultaneously, it is
called full duplex. The telephone is an example of this
type of communication.
17
17. 1-3: Types of Electronic
Communication
Half Duplex
The form of two-way communication in which only one
party transmits at a time is known as half duplex.
Examples are:
Police, military, etc. radio transmissions
Citizen band (CB)
Family radio
Amateur radio
18
18. 1-3: Types of Electronic
Communication
Analog Signals
An analog signal is a smoothly and continuously
varying voltage or current. Examples are:
Sine wave
Voice
Video (TV)
19
19. 1-3: Types of Electronic
Communication
Figure 1-5: Analog signals (a) Sine wave “tone.” (b) Voice. (c) Video (TV) signal.
20
20. 1-3: Types of Electronic
Communication
21
Digital Signals
Digital signals change in steps or in discrete increments.
Most digital signals use binary or two-state codes.
Examples are:
Telegraph (Morse code)
Continuous wave (CW) code
Serial binary code (used in computers)
21. 1-3: Types of Electronic
Communication
Figure 1-6: Digital signals (a) Telegraph (Morse code). (b) Continuous-wave (CW)
code. (c) Serial binary code.
22
22. 1-3: Types of Electronic
Communication
Digital Signals
Many transmissions are of signals that originate in
digital form but must be converted to analog form to
match the transmission medium.
Digital data over the telephone network.
Analog signals.
They are first digitized with an analog-to-digital (A/D)
converter.
The data can then be transmitted and processed by
computers and other digital circuits.
23
23. 24
1-4: Modulation and Multiplexing
Modulation and multiplexing are electronic
techniques for transmitting information efficiently from
one place to another.
Modulation makes the information signal more
compatible with the medium.
Multiplexing allows more than one signal to be
transmitted concurrently over a single medium.
24. 25
1-4: Modulation and Multiplexing
Baseband Transmission
Baseband information can be sent directly and
unmodified over the medium or can be used to
modulate a carrier for transmission over the medium.
In telephone or intercom systems, the voice is placed on
the wires and transmitted.
In some computer networks, the digital signals are applied
directly to coaxial or twisted-pair cables for transmission.
25. 26
1-4: Modulation and Multiplexing
Broadband Transmission
A carrier is a high frequency signal that is modulated by
audio, video, or data.
A radio-frequency (RF) wave is an electromagnetic
signal that is able to travel long distances through space.
26. 27
1-4: Modulation and Multiplexing
Broadband Transmission
A broadband transmission takes place when a carrier
signal is modulated, amplified, and sent to the antenna
for transmission.
The two most common methods of modulation are:
Amplitude Modulation (AM)
Frequency Modulation (FM)
Another method is called phase modulation (PM), in
which the phase angle of the sine wave is varied.
28. 29
1-4: Modulation and Multiplexing
Figure 1-8: Types of modulation. (a) Amplitude modulation. (b) Frequency modulation.
29. 30
1-4: Modulation and Multiplexing
Broadband Transmission
Frequency-shift keying (FSK) takes place when data
is converted to frequency-varying tones.
Devices called modems (modulator-demodulator)
translate the data from digital to analog and back again.
Demodulation or detection takes place in the receiver
when the original baseband (e.g. audio) signal is
extracted.
30. 31
1-4: Modulation and Multiplexing
Multiplexing
Multiplexing is the process of allowing two or more
signals to share the same medium or channel.
The three basic types of multiplexing are:
Frequency division
Time division
Code division
32. 33
1-5: The Electromagnetic Spectrum
The range of electromagnetic signals encompassing
all frequencies is referred to as the electromagnetic
spectrum.
34. 35
1-5: The Electromagnetic Spectrum
Frequency and Wavelength: Frequency
A signal is located on the frequency spectrum according
to its frequency and wavelength.
Frequency is the number of cycles of a repetitive wave
that occur in a given period of time.
A cycle consists of two voltage polarity reversals,
current reversals, or electromagnetic field oscillations.
Frequency is measured in cycles per second (cps).
The unit of frequency is the hertz (Hz).
35. 36
1-5: The Electromagnetic Spectrum
Frequency and Wavelength: Wavelength
Wavelength is the distance occupied by one cycle of a
wave and is usually expressed in meters.
Wavelength is also the distance traveled by an
electromagnetic wave during the time of one cycle.
The wavelength of a signal is represented by the Greek
letter lambda (λ).
36. 37
1-5: The Electromagnetic Spectrum
Figure 1-15: Frequency and wavelength. (a) One cycle. (b) One wavelength.
37. 38
1-5: The Electromagnetic Spectrum
Frequency and Wavelength: Wavelength
Wavelength (λ) = speed of light ÷ frequency
Speed of light = 3 × 108 meters/second
Therefore:
λ = 3 × 108 / f
Example:
What is the wavelength if the frequency is 4MHz?
λ = 3 × 108 / 4 MHz
= 75 meters (m)
38. 39
1-5: The Electromagnetic Spectrum
Frequency Ranges from 30 Hz to 300 GHz
The electromagnetic spectrum is divided into segments:
Extremely Low Frequencies (ELF)
30–300 Hz.
Voice Frequencies (VF)
300–3000 Hz.
Very Low Frequencies (VLF)
include the higher end of the
human hearing range up to
about 20 kHz.
Low Frequencies (LF)
30–300 kHz.
Medium Frequencies (MF)
300–3000 kHz
AM radio 535–1605 kHz.
39. 40
1-5: The Electromagnetic Spectrum
Frequency Ranges from 30 Hz to 300 GHz
High Frequencies (HF)
3–30 MHz
(short waves; VOA, BBC
broadcasts; government and
military two-way communication;
amateur radio, CB.
Very High Frequencies (VHF)
30–300 MHz
FM radio broadcasting (88–108
MHz), television channels 2–13.
Ultra High Frequencies (UHF)
TV channels 14–67, cellular
phones, military communication.
300–3000 MHz
40. 41
1-5: The Electromagnetic Spectrum
Frequency Ranges from 30 Hz to 300 GHz
Microwaves and Super High
Frequencies (SHF)
1–30 GHz
Satellite communication, radar,
wireless LANs, microwave ovens
Extremely High Frequencies (EHF)
Satellite communication, computer
data, radar
30–300 GHz
41. 42
1-5: The Electromagnetic Spectrum
Optical Spectrum
The optical spectrum exists directly above the
millimeter wave region.
Three types of light waves are:
Infrared
Visible spectrum
Ultraviolet
42. 43
1-5: The Electromagnetic Spectrum
Optical Spectrum: Infrared
Infrared radiation is produced by any physical
equipment that generates heat, including our bodies.
Infrared is used:
In astronomy, to detect stars and other physical bodies in the
universe,
For guidance in weapons systems, where the heat radiated
from airplanes or missiles can be detected and used to guide
missiles to targets.
In most new TV remote-control units, where special coded
signals are transmitted by an infrared LED to the TV receiver to
change channels, set the volume, and perform other functions.
In some of the newer wireless LANs and all fiber-optic
communication.
43. 44
1-5: The Electromagnetic Spectrum
Optical Spectrum: The Visible Spectrum
Just above the infrared region is the visible spectrum
we refer to as light.
Red is low-frequency or long-wavelength light
Violet is high-frequency or short-wavelength light.
Light waves’ very high frequency enables them to
handle a tremendous amount of information (the
bandwidth of the baseband signals can be very wide).
44. 45
1-5: The Electromagnetic Spectrum
Optical Spectrum: Ultraviolet
Ultraviolet is not used for communication
Its primary use is medical.
45. 46
1-6: Bandwidth
Bandwidth (BW) is that portion of the electromagnetic
spectrum occupied by a signal.
Channel bandwidth refers to the range of
frequencies required to transmit the desired
information.
46. 47
1-6: Bandwidth
More Room at the Top
Today, virtually the entire frequency spectrum between
approximately 30 kHz and 300 MHz has been spoken
for.
There is tremendous competition for these frequencies,
between companies, individuals, and government
services in individual carriers and between the different
nations of the world.
The electromagnetic spectrum is one of our most
precious natural resources.
47. 48
1-6: Bandwidth
More Room at the Top
Communication engineering is devoted to making the
best use of that finite spectrum.
Great effort goes into developing communication
techniques that minimize the bandwidth required to
transmit given information and thus conserve spectrum
space.
This provides more room for additional communication
channels and gives other services or users an
opportunity to take advantage of it.
48. 49
1-6: Bandwidth
Spectrum Management and Standards
Spectrum management is provided by agencies set up
by the United States and other countries to control
spectrum use.
The Federal Communications Commission (FCC)
and the National Telecommunications and
Information Administration (NTIA) are two agencies
that deal in spectrum management.
Standards are specifications and guidelines necessary
to ensure compatibility between transmitting and
receiving equipment.
49. 1-7: A Survey of
Communications Applications
Simplex
AM and FM
broadcasting
Digital radio
TV broadcasting
Digital television (DTV)
Cable television
Facsimile
Wireless remote control
Paging services
Navigation and
direction-finding
services
Telemetry
Radio astronomy
Surveillance
Music services
Internet radio and
video
50
50. 1-7: A Survey of
Communications Applications
Duplex
Telephones
Two-way radio
Radar
Sonar
Amateur radio
Citizens radio
Family Radio service
The Internet
Wide-area networks
(WANs)
Metropolitan-area
networks (MANs)
Local area networks
(LANs)
51