Question Paper of Communication Engineering

Communication EngineeringGroup A


Field theory: Fields, vector calculus, gradient, Divergence, curl, Gauss's laws. Stoke' theorem, Helmholtz Theorem. Electric field intensity and potential, conducting Boundaries, coaxial cylinders, Poisson's equations and Laplace equation. Ampere's circuital law, differential equation for vector potential. Magnetic polarization and field intensity, boundary conditions for Band H. Faraday's law. Time varying fields, displacement current.
Maxwell's equations in differential and integral forms.
Communication preliminaries. Signal representation in frequency and time domain. Fourier transforms, power Spectrum, energy density spectrum. ,Direct delta function. Orthogonal representatives of signals (Gram Schmidt
Procedure), autocorrelation, sampling theressare (Nyquist criterion). Random signal theory. Discrete probability theory, continuous random variables, probability density functions, ergodic processes, correlation function, spectral density, white noise.
Noise: Atmospheric, thermal, shot and partition noise, noise figure and experimental determination of noise figure, minimum noise figures in networks. Analog communication. Modulation theory and circuits. Amplitude modulation, AM-DSB, AM-DSB/SC, AM-SSB and their comparison. Modulating and detector circuits for AM, FM and phase modulation~ Automatic frequency control. Pulse modulation. PAM, PDM, PPM, PCM, delta modulation and circuits. Principle multiplexing FDM and TDM.


Group B

Transmission through network: Networks with random input, auto-correlations, special density and probability density input-output relationships, envelope of sine wave plus Gaussian noise, optimum systems and nonlinear systems. Maximum signal to noise ratio' criterion. Minimum mean square error criteria, equivalent noise bandwidth. SNR in envelope detectors and PCM systems. Comparison of modulation systems.
Digital communication: Basic information theory: Definition of information, entropy, uncertainty and information, rate of communication, redundancy, relation between systems capacity and information content of messages, discrete systems, discrete noisy channel, channel coding. Introduction to digital communication, quantization, PCM, log-PCM, DM, DPCM, AD, PCM and LPC for speech signals, TOM. Basehand transmission, optimum
detection, matched filter, optimum terminal filters. LSI pulse shapes for controlled ISI, line codes; digital RF modulation. Modems, performance of digital modulation systems. Synchronization. Timing recovery.

Recommended Books
1.J D Krans and D Fleisch. Electromagnetic with Applications. McGraw-Hill International, Tokyo.
2. DBA Carlson. An Introduction to Signals and Noise in Electrical Communication. McGraw-Hill International, Tokyo.
3.G Kennedy. Electronic Communication Systems. Prentice- Hall of India (P) Ltd., New Delhi.

4. M Schwartz. Information Transmission, Modulation and Noise. McGraw-Hill International, New York.

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