Communications I
Subject Code: ETM3046
Aim of Subject:
  • To introduce to students basic principles of modulation and receiver systems.
  • To introduce to students the occurrence of noise.
Learning Outcome of Subject: At the completion of the subject, students should be able to:
  • distinguish and describe the main features of analog and digital communication systems.
  • describe the essential elements of a communication system.
  • analyse signals in the time and frequency domains through Fourier analysis.
  • explain the need for various types of continuous-wave modulation in communication systems.
  • design basic analog modulation and demodulation schemes.
  • define the types of noise occur in communication systems and calculate the noise power.
  • calculate signal-to-noise ratio, noise figure and noise temperature for a single and cascaded stages.
  • define and describe the function of each block in a superheterodyne communication receiver.
  • undertake, under supervision, laboratory experiments to study the operation of an amplitude modulated transceiver.
  • perform computer simulations to investigate different angle modulation and demodulation methods.
Programme Outcomes:
  • Ability to acquire and apply fundamental principles of science and engineering(50 %)
  • Capability to communicate effectively(10%)
  • Acquisition of technical competence in specialised areas of engineering discipline(10%)
  • Ability to identify, formulate and model problems and find engineering solutions based on a systems approach(10%)
  • Ability to conduct investigation & research on engineering problems in a chosen fields of study(5%)
  • Understanding of the importance of sustainability and cost-effectiveness in design and development of engineering solutions(5%)
  • Ability to work independently as well as with others in a team(10%)
Assessment Scheme:
  • Lab Experiments - Work in group of 2, Lab report writing, Oral assessment at the end of lab (10% )
  • Tutorial / Assignment - Group assignment, Focus group discussion at tutorial, To enhance understanding of basic concepts in lecture (15% )
  • Test Quiz - Written exam(15% )
  • Final Exam - Written exam(60% )
Teaching and Learning Acitivities: 53 hours (42hr lectures, 5hr tutorials and 6hr laboratory experiments)
Credit Hours: 3
Pre-Requisite: None
  • Leon W. Couch, II, “Digital and Analog Communication Systems”, 6th Edition, Prentice Hall, 2001. (Textbook)
  • B.P. Lathi, "Modern Digital and Analog Communications Systems", 3rd Edition, OUP, 1998.
  • Taub & Schilling, "Principles of Communication Systems", McGraw-Hill, 1986.
  • P.H. Young, "Electronic Communication Techniques", Prentice Hall, 5th Edition, 2003.
  • M. Schwartz, "Information Transmission, Modulation and Noise", McGraw Hill, 1990.

Subject Contents

  • Principles of Communications

  • An elementary account of the types of transmission. Brief historical development on communications: telegraph, telephony, radio, satellite, data, optical and mobile communications, facsimile. Block diagram of a communication system. The frequency spectrum.
  • Spectral Analysis

  • Signals and vectors, orthogonal functions, Fourier series, Fourier integral, signal spectrum, convolution, power and energy, correlation.
  • AM and FM Modulation Theory

  • Reasons for modulation. Types of modulation. Amplitude modulation systems: Comparison of AM systems, Methods of generating, and detecting AM, DBS, SSB signals. Vestigial sideband. Frequency mixing and multiplying, frequency division multiplexing, applications of AM systems. Frequency modulation systems: Instantaneous frequency, frequency deviation, modulation index, Bessel coefficients, significant sideband criteria, bandwidth of a sinusoidally modulated FM signal, power of an FM signal, narrowband FM, direct and indirect FM generation, various methods of FM demodulation, discriminator, phase-lock loop; limiter, pre-emphasis and de-emphasis, stereophonic FM broadcasting.
  • Noise

  • Noise waveforms and characteristics. Thermal noise, shot noise, noise figure and noise temperature. Cascade network, experimental determination of noise figure. Effect of noise on AM and FM systems.
  • Superheterodyne AM Radio Receiver

  • Block diagram of a superheterodyne AM radio receiver, AM broadcast band and specification, signal sensitivity, aerial circuit, i.f. trap, RF amplifier design, frequency mixer, local oscillator design, intermodulation interference, adjacent channel interference, ganging, tracking error, intermediate frequency, automatic gain control, delay agc, diode detector, volume control.
  • Superheterodyne FM Radio Receiver

  • FM broadcast band specification, block diagram of a FM radio receiver, limiter and ratio detector, automatic frequency control, squelch circuit, FM mono and FM stereo receivers.


1. AM Modulation
2. FM Modulation with MATLAB and SIMULINK