Course Outline:

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Course Outline I. PRELIMINARY PERIOD (16
Hours) A. The Electromagnetic Spectrum and
Noise B. Decibels and Noise C. Amplitude
Modulation D. Receivers for AM
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II. MIDTERM PERIOD (16 Hours) A. Frequency
and Phase Modulation B. Digital Information C.
Digital Communication Fundamentals
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III. FINAL PERIOD (16 Hours) A. Digital
Communication System B. Digital Modulation and
Testing C. Other Topics D. Project Making
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References A. Communication Electronics by
Louis Frenzel B. Electronic Communication System
by George Kennedy C. Advanced Electronic Comm
System by Wayne Tomasi D. Fundamentals of
Microwave Comm by Manuel Rule E. ECE Reviewer,
Volume 2 by Edward Munar F. ECE Licensure
Guidebook by Ronnie Villamor G. Other
Electronic Communication/ECE Books
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INTRODUCTION TO ELECTRONIC COMMUNICATION SYSTEM
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• The field of electronics can be roughly divided
  into three major subfields computers,
  communications, and control.
• The largest field in terms of the sales of
  equipment and services and number of employees is
  the computer field.
• The communications industry is the second
  largest in size and is most certainly the oldest
  field.
• The smallest field is the control field.
• The computer industry is concerned with the
  development and servicing of computer hardware
  and software used by business, industry and
  government for the processing, storage and
  retrieval of data.

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• The communication industry is concerned with the
  electronic equipment used for the transfer of
  information between to or more points.
• That information may be voice, television,
  pictures, computer data, or some other form of
  electronic information.
• The control field is concerned with electric
  power as well as various kinds of electronic
  components.

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• Definition of Communication
• It is the basic process of exchanging
  information. It is what humans do to convey
  their thoughts, ideas and feelings to one
  another.
• It is to share ones thought with others. It is
  a bi-directional process. The term electronic
  communication refers to the sending, processing
  and reception of information by electrical means.

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• General Categories of Electronic Communication
• Depending upon the types of information to be
  sent and received following system have been
  developed over the years.
• Radio Communication
• Telephony
• Telegraphy
• Broadcasting
• Radar System
• Radio Telemetry
• Navigational Aids

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Milestone in Electronic Communication 1440
Gutenberg invents the printing press. 1644 Morse
patents the telegraph. 1866 First successful use
of transatlantic telegraph cable. 1876 Bell
invents and patents the telephone. 1879 Eastman
develop photographic film. 1887 Hertz discovers
radio waves. 1895 Marconi demonstrates wireless
telegraphy. 1901 Marconi makes first
transatlantic radio transmission. 1903 The
Fleming valve is invented.
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Milestone in Electronic Communication (cont
2) 1906 De Forest invents the triode vacuum tube
and the first radiotelephone broadcast. 1923 Tele
vision is invented. 1931 Radio astronomy is
discovered. 1940-45 Radar is perfected and
helps win WWII. 1948 The transistor is
invented. 1954 Color television broadcasting
begins. 1959 The integrated circuit is
invented. 1962 First communication satellite.
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• The Elements of a Communications System
• The basic components are a transmitter, a
  communication channel or a medium, and a
  receiver.
• In most systems, a human generates a message that
  we call the information, or intelligence signal.
  
• Noise is the general term applied to any
  interference that degrades the transmitted
  information.
• The transmitter is a collection of electronic
  components and circuits designed to convert the
  information into a signal suitable for
  transmission over a given communication medium.

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• The Elements of a Communications System
• The communication channel is the medium by which
  the electronic signal is sent from one place to
  another.
• Radio is the broad general term applied to any
  form of wireless communication from one point to
  another.
• The receiver is another collection of electronic
  components and circuits that accept the
  transmitted message from the channel and convert
  it back into a form understandable by humans.
• Noise is random, undesirable electric energy
  that enters the communications system via the
  communicating medium and interferes with the
  transmitted message.

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• Sources of Noise
• Internal Source (Transmitter/Receiver)
• Atmosphere
• Outer Space
• Manufactured equipment
• External Interference
• Thermal agitation of atoms

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The Elements of a Communications System
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Types of Electronic Communications 1. According
to Mode of Transmission a. Simplex b.
Duplex Half-Duplex
Full-Duplex Full-Full-Duplex c.
Echoplex
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Types of Electronic Communications 2. According
to the intelligence signals transmitted a.
Analog b. Digital c. Hybrid 3.
According to type of transmission method a.
Baseband b. Broadband
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Modulation, defined Modulation is the process of
having a baseband voice, video or digital signal
modify another, higher-frequency signal called
the carrier. The information to be sent is said
to be impressed upon the carrier. The carrier is
usually a sine wave that is higher in frequency
than the highest intelligence signal frequency.
Three basic characteristics of the carrier can be
changed by the information signal amplitude,
frequency, and phase. The information or
intelligence signal is also called the modulation
signal or wave.
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Modulation, defined Common Categories of
Modulation 1. Analog Modulation a.
Amplitude Modulation (AM) b. Angle
Modulation Frequency Modulation
(FM) Phase Modulation (PM) 2.
Digital Modulation
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Amplitude Modulation
Sinusoidal modulating wave
Sinusoidal unmodulated carrier waver
Amplitude Modulated Wave
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Sinusoidal modulating signal
Frequency Modulation
t
Frequency modulated wave
t
Varying frequency sinusoidal carrier
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Modulation The higher-frequency carrier signal
is more compatible with the medium (such as free
space) and propagates through it with greater
efficiency. At the receiver the carrier is
demodulated to extract the original baseband
information signal and transmitted message.
Another name for the demodulation process is
detection. The use of modulation also permits
another technique known as multiplexing to be
used. Multiplexing is the process of
transmitting two or more signals simultaneously
over the same channel.
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Survey of Communications applications Simplex 1.
AM and FM Radio broadcasting 2. TV
broadcasting 3. Cable television 4.
Facsimile 5. Wire remote control 6. Paging
services 7. Navigation and direction-finding
services.
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Survey of Communications applications Simplex 8.
Telemetry 9. Radio astronomy 10.
Surveillance 11. Teletext and Viewdata
12. Music Services
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Survey of Communications applications Duplex 1.
Telephones 2. Two-way radio 3. Radar 4.
Sonar 5. Amateur radio 6. Citizens radio 7.
Data Communications 8. Local area network (LAN)

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THE ELECTROMAGNETIC SPECTRUM
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The Electromagnetic Spectrum Before it can be
transmitted, information must be converted into
electronic signals compatible with the medium.
For example, a microphone changes voice into a
voltage of varying frequency and amplitude. This
baseband signal is then passed over wires to a
receiver or headphone. This is the way the
telephone system works. A tremendous amount of
information is transmitted in this way. These
so-called electromagnetic signals travel through
space for long distances. Electromagnetic
signals are also referred to as radio-frequency
(RF) waves.
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The Electromagnetic Spectrum Electromagnetic
waves are signals that oscillate that is, the
amplitudes of the electric and magnetic fields
vary at specific rate. This entire range of
frequencies is referred to as the electromagnetic
spectrum. Remember the relationship between
frequency f and wavelength ?. ? c/f where ?
wavelength, in meters (m) c speed of
light, 3 x 108 m/s f frequency, in Hertz (Hz)
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The Electromagnetic Spectrum Frequency is simply
the number of times a particular phenomenon
occurs in a given period of time. It may be the
number of voltage polarity alternations or
electromagnetic field oscillations that take
place in one second. Each alternation or
oscillation is called a cycle and the frequency
is measured in cycles per second (cps. In
electronics, the term hertz is used to express
frequency in cps. 60 cps 60 Hz.
Positive alternation
V
0
t
Negative alternation
cycle
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The Electromagnetic Spectrum Wavelength is also
the distance travelled by an electromagnetic wave
during the time of one cycle. Electromagnetic
waves travel as a speed of 300,000,000 meters per
second (c). ? c/f
1 wavelength
0
1 wavelength
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The Electromagnetic Spectrum Name Frequency W
avelength Extremely Low Frequency (ELF) 30-300
Hz 107 - 106 m Voice Frequency (VF)
300-3000 Hz 106 - 105 m Very Low Frequency
(VLF) 3-30 kHz 105 - 104 m Low Frequency
(LF) 30-300 kHz 104 - 103 m Medium Frequency
(MF) 300-3000 kHz 103 - 102 m High
Frequency (HF) 3-30 MHz 102 - 101 m Very High
Frequency (VHF) 30-300 MHz 101 - 1 m
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The Electromagnetic Spectrum Name Frequency W
avelength Ultra High Frequency (UHF)
300-3000 MHz 1 - 10-1 m Super High Frequency
(SHF) 3-30 GHz 10-1 - 10-2 m Extremely High
Frequency (EHF) 30-300 GHz 10-2 - 10-3
m Infrared - 0.7 - 10 ?m The
Visible spectrum (light) - 0.4 - 0.8 ?m
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Bandwidth Bandwidth is that portion of the
electromagnetic spectrum occupied by a signal.
It is also the frequency range over which an
information signal is transmitted or over which a
receiver or other electronic circuit operates.
More specifically, bandwidth (BW) is the
difference between the upper and lower frequency
limits of the signal or the equipment operation
range. The upper frequency is f2 and the lower
frequency is f1. The bandwidth then is BW f2
- f1 3000 - 300
2700 Hz
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Bandwidth When information is modulated onto a
carrier somewhere in the electromagnetic
spectrum, the resulting signal occupies a small
portion of the spectrum surrounding the carrier
frequency.
Bandwidth (BW)
f1 300 Hz
f2 3000 Hz
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NOISE
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NOISE Noise - Any unwanted form of disturbance
of signal or energy tending to interfere with the
proper and easy reception and reproduction of
unwanted signal. General Categories 1.
Uncorrelated Noise - noise present regardless of
whether there is a signal present or not. a.
External noise - generated external to acircuit
and allowed to enter the circuit. b. Internal
noise - electrical interference generated within
a device.
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NOISE 2. Correlated Noise - unwanted electrical
energy that is present as a direct result of a
signal, such as harmonic and intermodulation
distortion.
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UNCORRELATED NOISE Types of External Noise 1.
Atmospheric noise - static caused by lightning
discharges and thunderstorms. 2.
Extraterrestrial noise a. Solar Noise - sunspot
activity, solar noise, corona flares - cyclic
electrical disturbance every 11 years and
supercycles every 100 years b. Galactic or
cosmic noise - thermal or lack body noise from
distant stars and meteors.
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UNCORRELATED NOISE 3. Man-made/Industrial noise
- from arc discharges from motors, welding
machines, ignition systems, switching gears,
fluorescent lamps, starters, etc.
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UNCORRELATED NOISE Types of Internal Noise 1.
Thermal Noise - noise from thermal agitation of
active and passive devices resulting from rapid
and random motion of molecules. The temperature
of a body is the statistical root mean square
value of the velocity of motion of particles in
the body. 2. Shot Noise - noise from quantum
flow of electricity in a transmission system or
the random variations or arrival times of
electrons or holes at the input electrodes of an
amplifier and appears as a variable noise current
superimposed on the output.
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UNCORRELATED NOISE In ?2eldB In rms shot
noise current in amperes e electron charge
1.602 x 10-19 coulomb Id diode dc current B
bandwidth in Hertz 3. Transit Time Noise - high
frequency noise resulting from delayed travel of
electrons from emitter-collector of a vacuum tube
or semiconductor
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UNCORRELATED NOISE Miscellaneous Noise 1.
Flicker Noise - low frequency noise from carrier
density fluctuations. It is proportional to
emitter current and junction temperature,
inversely proportional to frequency. It is
negligible at frequencies above 500 Hz. 2. Mixer
Noise - cause by low transconductance of mixers
compared to amplifier and inadequate image
frequency rejection. 3. Generation-Recombination
Noise - random fluctuation of semiconductor
conductivity giving rise to noise current when DC
flows through the semiconductor.
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UNCORRELATED NOISE Miscellaneous Noise 4.
Crosstalk - interference signal from one channel
to another. Resistor Noise Power, Pn kTB Pn
maximum resistor noise power output k
Boltzmanns constant 1.39 x 10-23 Joules/K T
absolute temperature in Kelvin (k 273.15 ?C)
B bandwidth in Hertz
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UNCORRELATED NOISE Noise Voltage (Vn) and Noise
Current (In) Vn ?4kTBRL In ?4kTBG k
Boltzmanns constant T absolute temperature RL
load resistance G conductance 1/R B
bandwidth
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UNCORRELATED NOISE Noise Voltage (Vn) from
Several Sources in Series Vn ?4kTBRT where RT
R1 R2 R3 . . . Rn
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CORRELATED NOISE 1. Harmonic Distortion -
unwanted multiples of a signle frequency sine
that are created when the sine wave is amplified
in a non-linear device, such as large-signal
amplifier THD Vhigher/Vfund x 100 2.
Intermodulation Distortion - unwanted
cross-product (sum and difference) frequencies
created when two or more signals are amplified in
a non-linear device
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DECIBEL AND NOISE CALCULATION