COMUNICAZIONI DIGITALI M - Z

Knowledge of main principles of analog and digital transmission on a physical channel, both in base band and high frequencies.

Ability to evaluate bit error rate and power consumption of analog and digital transmissions.

Knowledge of the main analog modulations

Knowledge of the main digital modulations

The course is composed by a part of theory (35 hours), and a part of practice (15 hours).

1. BASEBAND PULSE AND DIGITAL SIGNALING

• Reference scheme; Pulse Amplitude Modulation; Transmission formatting filter
• Line Codes and Spectra: Binary Line Coding; Power Spectra for Binary Line Codes; Differential Coding
• Multilevel Polar NRZ Signals: Orthogonal and orthonormal Series Representation of Signals; Power Spectra for multilevel Line Codes; Spectral efficiency of digital codes.
• Intersymbol Interference (ISI): Nyquist’s First Method (Zero ISI). Raised Cosine-Rolloff Nyquist Filtering. Nyquist’s Second and Third Methods for Control of ISI
• Bit error rate (ber) for base band digital transmissions: Reference scheme of a digital receiver. General Results. Results for Gaussian Noise. Results for White Gaussian Noise and Matched-Filter Reception. Performance of Baseband Binary Systems Unipolar Signaling. Polar Signaling. Bipolar Signaling.

2. Baseband transmission of analog signals

• PCM modulation
• Sampling, Quantizing, and Encoding
• Bandwidth of PCM Signals
• Effects of Noise
• Nonuniform Quantizing: µ-Law and A-Law Companding.
• Telephone PCM
• PCM applied to HiFi audio systems

​3. Analog modulations

• Complex Envelope Representation of Bandpass Waveforms; Definitions: Baseband, Bandpass, and Modulation

• Amplitude Modulation (AM, DSB-SC, SSB, VSB): Complex Envelope and modulated signal; Spectrum, mean power, peak power and modulation efficiency.
• Phase Modulation and Frequency Modulation: Complex Envelope and modulated signal; Spectrum, mean power, peak power and modulation efficiency; Carson bandwidth
• Noise effects on analog modulations: Basaband SNR, SNR calculated at the input and the output of the receiver demodulator.

4. Binary Modulated Bandpass Signaling

• On-Off Keying (OOK): Complex Envelope and modulated signal
• DSP of the complex envelope and the modulated signal; Bandwidth
• Binary Phase-Shift Keying (BPSK): Complex Envelope and modulated signal
• DSP of the complex envelope and the modulated signal; Bandwidth
• Frequency-Shift Keying (FSK): Complex Envelope and modulated signal; DSP of the complex envelope and the modulated signal; Bandwidth; Example: V.21 modem
• Multilevel Modulated Bandpass Signaling: Complex Envelope and modulated signal; Quadrature Phase-Shift Keying and M-ary Phase-Shift Keying; Quadrature Amplitude Modulation (QAM)
• Bit Error Rate – BER: BER derivation for ASK, BPSK, FSK, MPSK, QAM

• [Cou] Leon W. Couch, Digital & Analog Communication Systems (8th Edition), Pearson Education Limited, 2013.
• [Pro] J. G. Proakis, M. Salehi, Communication System Engineering, Prentice Hall