The class provides the basic knowledge about telecommunications signals and systems, focusing in particular on the transmission through modulation of analog and digital signals
- Leon W. Couch Fondamenti di Telecomunicazioni, Edizioni Apogeo
- S. Haykin: “Communication systems”, Ed. Wiley.
- G. Benelli, V. Cappellini, E. Del Re: “Note di comunicazioni elettriche” Ed. Libreria Alfani.
- V. Lottici “Esercizi di comunicazioni elettriche” Edizioni ETS Pisa
Learning Objectives
1) Knowledge of the basic telecommunications principles , of the signals employed and of their propagation properties
2) Knowledge of the different analog and digital signals modulation and demodulation methods
3) Ability to characterize, analyse and quantify signal disturbances and their effects
4) Ability to analyse and compare different transmission and reception, modulation and demodulation schemes
Prerequisites
It is assumed that the student has a sound understanding of Signal Theory: Fourier theory of deterministic signals (both periodic and aperiodic), random variables, random processes and their spectral analysis
Teaching Methods
Lessons and classrom exercises
Type of Assessment
The exam is oral. The objective is to assess:
- through theoretical questions, the acquired knowledge of transmission,modulation and demodulation techniques of analog and digital signals, as well as of the systems utilized
- through numerical exercises, the acquired analytical ability to solve simple transmission or reception problems of the information-carrying signals.
Course program
The program is the following:
1) Introduction to communication systems: information and noise, information sources, sketch of a communications system, wireless and wired communications systems, frequency allocations, propagation in wireless communications systems
2) Disturbance over communications systems: band filtered white noise, thermal noise, noise figure and noise temperature, noise figure of cascaded systems
3) Analog modulations: classic AM, AM-DSB, AM-SSB, angle modulations (PM e FM). Modulators and demodulators, performance in noise, threshold effect. Superheterodyne and omodyne receivers. Signal multiplexing: FDM e TDM.
4) Digital modulations. Baseband impulse modulations: "flat top" and "natural gating" PAM, PDM, PPM, quantized impulse modulations, PCM. Line codes: unipolar and bipolar NRZ and RZ. Gray coding. Binary digital modulations: OOK, BPSK, FSK and CPFSK. Relationship between total SNR, SNR per bit and spectral efficiency. Multilevel modulations: M-PAM, M-PSK (QPSK and OQPSK), QAM. Transmission bandwidth and spectral efficiency. Error probability: decision regions and maximum likelihood receiver. Optimum receiver schemes. Error bound.