SIGNALS AND SYSTEMS FOR TELECOMMUNICATIONS
The aim of this course is to provide basic principles of spectral analysis of continuous and discrete signals and of their transformation by linear and nonlinear systems, of the probability theory, random variables, random processes, and of signal transmission techniques through noisy channels. Such topics are fundamental both for the comprehension of the content of other courses in the telecommunications field and in relation to methods and applications that make use of signals.
The purpose of this course is to provide the students with the necessary principles and notions to understand the operation of a telecommunication system and to be able, in further occasions, to examine it in depth. The introduction of the concepts of deterministic and random signal, filtering and frequency analysis, proves useful to reach such an objective.
AIMS AND LEARNING OUTCOMES
Learn to evaluate the characteristics of a signal (band occupancy, power, periodicity, etc.); design an analog-to-digital transformation, a filter, a modulation; understand the operations and the block diagrams of both baseband and band-pass signal transmission systems through noisy channels; analyze noise and signal sources from the statistical and the spectral viewpoints; evaluate the performances of a simple transmission system.
Knowledge of the topics of the basic math courses.
Class lectures and lab exercises.
Linear time-invariant systems (and filters). Impulse response and convolution integral. Fourier transform. Characteristic functions and frequency responses of linear time-invariants systems. Low-pass, band-pass, and high-pass filtering. Signal power/energy and power/energy spectral density. Sampling theorem. Ideal and real sampling. . Digital coding of analog signals by PCM (A/D and D/A conversions). PAM digital transmission over broadband and narrowband channels. Time-division (TDM) and frequency-division (FDM) multiplexing.
Probability theory, conditional probability, independent events, joint experiments, repeated trials, law of large numbers. Random variables, probability distribution and density functions, functions of a random variable, expectation, variance, moments. Random variable pairs, joint distribution and density functions, covariance and correlation coefficient. Sample-mean and sample-variance. Random processes, stationary processes, autocorrelation function and power spectral density, ergodic processes. Telegraphic and random binary signals. White noise.
Bandpass transmission methods for continuous signals: linear (AM, DSB, SSB, VSB) and angular (FM, PM) analog modulations. Bandwidth requirements. Basic diagrams of modulation and demodulation systems. Computation of the destination S/N ratio in linear and angular modulation systems. Threshold effect. Pre-emphasized FM. Comparison among different techniques (performances, cost, use).
Teaching material and reference textbooks
- Slides utilized during the lectures (available in Aulaweb).
- A.B. Carlson, P. B. Crilly, J. C. Rutledge, Communication Systems, Mc Graw-Hill, 2001 (4th edition).
- A. Papoulis, S. U. Pillai, Probability, Random Variables and Stochastic Processes, McGraw-Hill, 2002 (4th edition).
- R. Cusani, Teoria dei Segnali, Edizioni Ingegneria 2000, Roma, 1996.
- C. Prati, Segnali e sistemi per le telecomunicazioni, McGraw-Hill, Milano, 2003
- A. Papoulis, Fourier Integral and its Applications, Mc Graw-Hill, 1962.
SEBASTIANO SERPICO (President)
ANDREA TRUCCO (President Substitute)
Class lectures and lab exercises.
Examination modalities will depend on and will be specified as a function of the evolution of the COVID-19 pandemic and the related social distancing measures. If the sanitary emergency subsides, the examination will include a written exam, possibly replaced by optional intermediate tests, and an oral exam.
Written exams will evaluate the synthesis and analysis ability of simple telecommunication systems and their subparts. Oral exams extend such an evaluation through the discussion and motivation of the choices made.