B.Tech-B.Tech Electrical Engineering 6th Sem 6EE6.3 Digital Communication and Information Theory 6E3116(Rajasthan Technical University-2011)
6E3116
B. Tech. VIth Semester (MainlBack) Examination, May/June - 2011
Electrical Engineering (Common for EE And EX)
6EE6.3 Digital Communication and Information Theory
Time : 3 Hours
Maximum Marks: 80
Min. Passing Marks : 24
Unit - I
Q.1. a) Draw and explain the working of delta modulation also, explain adaptive delta modulation compare its perfonnance with delta modulation. [8]
b) A delta modulator system is designed to operate at ten times the Nyauist rate for signal having a band width equal to 6 KHz. Calculate the maximum amplitude
of a 4 KHz input sinusoidal for which the delta modulator does not have slope overload. The step size is 500 mV. [8]
OR
Q.2. a) Derive the signal to quantization noise ratio in pulse code modulation techniques. [8]
b) Write short note on :- [8]
i) Match filter detection
ii) TI Carrier System.
Unit- II
Q.3. a) Draw for explain the working of generation and detection of minimum shiftkeying scheme. What are its merits and demerits? [8]
b) Draw and explain the working of generation and detection of BPSK signal. [8]
OR
Q.4. a) Explain generation and detection of FSK. [8]
b) Explain generation and detection of ASK. [8]
Unit - III
Q.5. a) . Calculate error probability of ASK with derivation. [8]
b) Calculation error probability of PSK with derivation. [8]
OR
Q.6. a) Calculate error probability of FSK with derivation. [8]
b) Calculation error probability of MSK with derivation. [8]
Unit - IV
Q.7. a) Derive the mathematical expression for channel capacity to transmit the information through it. The channel capacity is
C = B log2(1 + C/N ) b/s, where
B = Bandwidth, S = Signal power, N = Noise power. [10]
b) Derive the expression for joint and conditional entropy is given from
H(X,Y) =H(X/Y)+H(Y). [6]
OR
Q.8. a) Describe the Shanon's theorem also drive the expression for Shannon's bound. [6]
b) Define entropy. An analog signal having 4 KHz bandwidth is sampled at 1.25 times the Nyauist rate, and each sample is quantized into one of equally likely levels. The successive samples are statistically independent.
i) Information rate of the source,
ii) Find the signal to Noise ratio for error free transmission if band width is 10 KHz. [10]
Unit - V
Q.9. a) Find the generator matrix corresponding g(X) = 1 +X2 + X3 for a (7,4) cyclic code. [8]
b) Consider a (7, 4) linear block code, whose generator matrix is given by
i) Find all code vectors of this code.
ii) Find the parity check matrix at this code.
iii) Find the minimum weight of this code. [8]
OR
Q.10. a) Write short note on Convolutional codes. [8]
b) For the (7, 4) Hamming code, the parity check matrix H is given by
Find :-
i) Construct th e generator matrix
ii) The code work that begin with 1010. [8]
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