M.Tech DEGREE I SEMSTER EXAMINATION IN ELECTRONICS

(SIGNAL PROCESSING) – MODEL PAPER – 2012

SP103 – DIGITAL COMMUNICATION

MODULE-1

1. A. (a) Differentiate between Central Chi square distribution and Rayleigh distribution of a

random variable . (5)

(b) State and prove the Central limit theorem. (5)

OR

B. (a) Give the properties of autocorrelation function . (4)

(b) Distinguish between Chebyshev bound and Chernoff bound . (6)

MODULE-2

2. A. (a) Explain the characterization of band pass signals,in terms of its quadrature

Components. (5)

(b) Explain Gram-Schmidt procedure for orthogonalization of signals. (5)

OR

B. (a) Explain MAP and maximum likelihood decision rule. (5)

(b) Draw the signal space diagram for BPSK and QPSK signals and explain. (5)

MODULE-3

3. A. (a) Explain the working of a matched –filter and derive the expression for SNR . (10)

OR

B. (a) Explain the working of an optimum demodulator for binary signals in AWGN

channels . (5)

(b) Derive the probability of error of correlation receiver in unipolar signalling scheme (3)

(c) Give the correlation realization of matched filter. (2)

MODULE-4

4.A. (a) Distinguish between Rayleigh fading channel and a Ricean fading channel. (5)

(b) Explain wide band fading channel model .Give the expression for autocorrelation

function. (5)

OR

B. (a) Evaluate the performance of a RAKE demodulator under slow fading conditions. (5)

(b) Explain narrow band fading channel model .Give the expression for autocorrelation

function. (5)

MODULE-5

5. A. (a) State and explain Nyquist criterion for zero ISI (5)

(b) Explain partial response signalling . (5)

OR

B. (a) What is linear equalization. Draw the block diagram of a channel with zero forcing

equalizer and explain. (5)

(b) Explain coefficient estimation in decision feedback equalizer . (5)