COMMUNICATION ENGINEERING

Group 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. Baseband transmission, optimum detection, matchedfilter, optimum terminal filters. LSI pulse shapes for controlled ISI, line codes; digital RF
modulation. Modems, performance of digital modulation systems. Synchronization. Timing
recovery.

 

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