# Introduction to Telecommunications

Professors Athanasios Kanatas
Evangelos Haleplidis
Course category Core
Course ID DS-301
Credits 5
Lecture hours 3 hours
Lab hours 2 hours
Digital resources View on Aristarchus (Open e-Class)

### Learning Outcomes

The course seeks to introduce the students to telecommunication systems by focusing on physical layer technologies. By concluding the course, students are able to

• thoroughly understand the principles that govern the transmission in telecommunication systems as well as the principles of analysis and design of telecommunication systems
• recognize the discrete functions performed in a telecommunication system
• distinguish and explain the mathematical tools describing the functions of a telecommunication system
• apply mathematical notations and tools in the analysis and synthesis of both existing and new analog and digital telecommunication systems

By concluding the lab sessions students are able to

• identify and apply the acquired theoretical knowledge in real-world problems
• use and exploit laboratory equipment for observation, measurement and comparison of real signals.

### Course Contents

Introduction to signal theory (categories and elementary signals, basic signal conversions) and to telecommunication systems (categories, Linear Time Invariant systems). The concepts of impulse response, convolution, autocorrelation and cross-correlation are also introduced. Next, the representation of signals is explained in the case of digital modulation techniques by introducing the geometric signal representation (vectors in spaces, Hilbert space, bases and representation of signals using orthogonal signals, Gram-Schmidt ortho-normalization, linear systems and eigenfunctions).

Then the Fourier series theory is presented (Fourier series expansion, properties, real signals and expansion in Fourier trigonometric series, LTI system response in periodic signals, Parseval theorem for periodic signals) as well as the Fourier transformation is examined (Fourier transform for real signals, properties, Fourier transform for periodic signals, energy & power spectral densities). Subsequently, students are introduced to the concept of filters and noise (types of ideal filters – characteristics, transmission without distortions and type of distortions, white noise and noise power spectral density). Then, an extended reference is made to the application of Fourier analysis in telecommunication systems. The concept of passband signals and systems is developed by means of the Hilbert transformation, the pre-envelope and the complex envelope. Sampling theorem and Nyquist rate is also extensively discussed. Analog modulation techniques (amplitude and frequency) are presented providing the modulation and demodulation procedures and systems in time and frequency domains.

In addition, extra content (in evdoxos.ds.unipi.gr) like articles, audiovisual lectures and Internet addresses, as well as exercises for student’s practice are posted electronically. Case studies, exemplary problems and methods for solving them are presented.