This subject provides a mathematical analysis of Digital Communication systems.
Digital Transmission of Analogue Signals:
Review of sampling and pulsecode modulation; ideal sampling and reconstruction, sampling theorem,natural sampling, flat top sampling, aliasing. PAM, TDM, bandwidth requirements.PCM generation and reconstruction, Quantizing, Quantization noise,companding, encoding, bandwidth requirements of PCM.
Correlation And Spectral Density:
Definition of energy and power signals, signalpower and scalar product, Schwarz's inequality, interpretation of scalarproduct. Correlation of energy and power signals; Crosscorrelation,autocorrelation, interpretation of correlation, properties of correlation.Superposition of average power for uncorrelated signals. Relationships betweeninput and output correlations for LTI systems, Energy and power spectraldensities. Wiener-Khinchin relations.
Stochastic Processes:
Introduction to stochastic processes; statistics of randomprocesses, statistical averages, autocorrelation, autocovariance, stationarity,crosscorrelation and cross-covariance, SSS and WSS, time averages andergodicity. Correlation and power spectral densities, Wiener-Khinchin relations,cross spectral densities. Transmission of random processes through linearsystems, system response, mean and autocorrelation of the output, powerspectral density of the output. Special classes of stochastic processes; whitenoise, band-limited white noise, narrowband random processes. Derivation ofSNR's for various CW systems.
Baseband Digital Transmission:
Signalling formats; description of generaldiscrete PAM signal, unipolar and polar signalling (NRZ and RZ), Manchestersignalling, bipolar signalling (RZ and NRZ), HDB3. Transmission Limitations:intersymbol interference: model of baseband binary PAM system, analysis,Nyquist criterion for distortionless baseband transmission in the absence ofnoise, the ideal Nyquist channel, raised-coisine filter, roll-off factor,relationship between ISI, bandwidth and signaling rate. Equalisation, the zero-forcing equaliser, expressions for the equaliser output and the tap weights, examples.
Binary Signal Detection
Hypothesis testing, maximum likelihood detector, probability of error withgaussian noise, decision thresholds. Regeneration. Optimum detection: thematched filter, correlator detector, the integrate and dump filter, probabilityof error for binary transmission systems.
Digital Carrier Modulation Systems:
ASK, FSK, PSK. Optimum binary detection,Probability of error. M-PSK and QAM, comparison.
Synchronization Techniques
Description and analysis of the phase locked loop, baseband model, analysis of various loop filters. Closed loop bit synchronisation, the early late gate synchroniser, scramblers and PN sequence generators. Carrier synchronisation, the squaring loop and the mth power loop. Frame synchronization.
| Module Content & Assessment | |
|---|---|
| Assessment Breakdown | % |
| Other Assessment(s) | 27 |
| Formal Examination | 70 |