Transcript File - The Mohsin Jahan

BS Evening (Reg.)
10 Feb, 16
Introduction to
Communication Systems
Lecture - 1
Communication Systems
Waseem Gulsher
Waseem Gulsher
MS (Electronics) in progress
from PAF-KIET
Email: [email protected]
Contact: 0333-5454993
Recommended Text Book
Electronic Communication
Systems
George Kennedy
Electronic Communication
Systems
Wyne Tomasi
Grading
Mid Term
Assignments
Quizzes
Class
Participation
Attendance
25
10
10
5
Midterm Paper
• Three out of five questions
Final Term Paper
• Five out of Eight questions
Final
Total
50
100
Rules & Regulations
No need to take permission while
entering or leaving the class during lecture.
•
There will be three assignments during
semester and average of best two will be
taken for sessional marks.
•
There will be five quizzes during
semester and average of best four will be
taken for sessional marks.
•
Assignments are to be submitted in a
file / folder.
•
Rules & Regulations
No marks will be given for copy work.
Assignments must be submitted within
one week.
•
If assignment is submitted with one
week delay, it will marked out of 5 marks
instead of 10
•
No assignment will be accepted after 2
weeks.
•
•
Rules & Regulations
All lectures will be delivered on
multimedia.
•
Lectures (including assignments) will
be email on your addresses within 24 hours.
•
If not received, you can text me on my
cell phone.
•
There will be no compromise on
attendance in any case.
•
Introduction to
Communication Systems
Significance of
Human Communication
Communication is the
exchanging information.
process
of
Main barriers are language and distance.
Contemporary society’s emphasis is now
the
accumulation,
packaging,
and
exchange of information.
Significance of
Human Communication
Methods of communication:
1.
2.
3.
4.
Face to face
Signals
Written word (letters)
Electrical innovations:
 Telegraph
 Telephone
 Radio
 Television
 Internet (computer)
Communication Systems
Basic components:



Transmitter
Channel or medium
Receiver
Noise degrades or interferes with transmitted
information.
Communication Systems
A general model of all 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.

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).

Receiver
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.

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

Attenuation & Noise
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.

Noise is random, undesirable electronic
energy that enters the communication system via
the communicating medium and interferes with
the transmitted message.

Types of Electronic
Communication
Electronic communications are classified
according to whether they are
1.
2.
One-way (simplex) or two-way (full duplex
or half duplex) transmissions
Analog or digital signals.
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)

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.

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
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)
Analog Signals
Analog signals (a) Sine wave “tone.” (b) Voice.
(c) Video (TV) signal.
Types of Electronic
Communication
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)
Digital Signals
Figure 1-6: Digital signals (a) Telegraph (Morse code). (b)
Continuous-wave (CW) code. (c) Serial binary code.
Thank You