30820-Communication Systems
Week 1 – Lecture 1-3
(Ref: Chapter 1 of text book)
INTRODUCTION
Course Information
• Instructor: Dr. Adnan Zafar (Assistant Professor)
– Office: Room No 2, EE Department, Block VI
– Email: adnan.zafar@ist.edu.pk
• Text Book: “Modern Digital and Analog Communication Systems”, 4th Edition,
By B. P. Lathi, Zhi Ding
• Program Learning Outcome: The course is designed so that students will
achieve
– Problem Analysis: PLO-02
– Design/Development of Solution: PLO-03
• Course Learning Outcome: Upon successful completion of the course, the
students will be able to
– Apply the concepts of signals and systems to different communication systems
– Analyze different analog and digital transmission schemes
– Design amplitude modulation (AM) and frequency modulation (FM) transmitter
• Online Resource: https://youtube.com/playlist?list=PLG8mrLNiKT2G4dwycq9kUzxm8j8Ihiux6
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Online Resource
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Class Instructions
• Be punctual
• No use of cell phones
• No tolerance for proxy in class attendance
• 80% attendance requirement
• Coordinate through CR
• Deadlines are fixed and not flexible
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Assessment
Quizzes (surprise, Announced) 20%
Assignments 10%
OHT Exams (7 week & 13 Week)
th th 25%
Final Exam (Scheduled Week) 45%
Total 100%
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Course Contents
• Chapter No 1: Introduction
• Chapter No 2: Signal and Signal Space
• Chapter No 3: Analysis and Transmission of Signals
• Chapter No 4: Amplitude Modulation and Demodulation
• Chapter No 5: Angle Modulation and Demodulation
• Chapter No 6: Sampling and Analog to Digital Conversion
• Chapter No 7: Principles of Digital Data Transmission
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What’s Communication?
• Communication involves the transfer of information from one point to
another.
• Three basic elements
– Transmitter: converts message into a form suitable for transmission
– Channel: the physical medium, introduces distortion, noise, interference
– Receiver: reconstruct a recognizable form of the message
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Analog Messages
• Early analog communication
– telephone (1876)
– phonograph (1877)
– film soundtrack (1923, Lee De Forest, Joseph Tykocinski-Tykociner)
• Key to analog communication is the amplifier (1908, Lee De Forest, triode
vacuum tube)
• Broadcast radio (AM, FM) is still analog
• Broadcast television was analog until 2009
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Digital Messages
• Early long-distance communication was digital
– semaphores, signal flags, smoke signals, bugle
calls, telegraph
• Teletypewriters
– Baudot (1874) created 5-unit code for alphabet
– Today baud is a unit meaning one symbol per
second
– Working teleprinters were in service by 1924 at
65 words per minute
• Fax machines: Group 3 (voice lines) and Group
4 (ISDN)
– First fax machine was invented by Alexander
Bains in 1843
– Pantelegraph (Caselli, 1865) set up telefax
between Paris and Lyon
• Ethernet, Internet
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Communication System Block Diagram
(Basic)
• Source encoder converts message into message signal (bits)
• Transmitter converts message signal into format appropriate for channel
transmission (analog/digital signal)
• Channel conveys signal but may introduce attenuation, distortion, noise,
interference
• Receiver decodes received signal back to message signal
• Source decoder decodes message signal back into original message
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Communication System Block Diagram
(Advanced)
• Source encoder compresses message to remove redundancy
• Encryption protects against eavesdroppers and false messages
• Channel encoder adds redundancy for error protection
• Modulator converts digital inputs to signals suitable for physical channel
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