Name of the College : Dasari Jhansi Rani Institute Of Engineering And Technology
University : JNTUK
Department : Computer Science And Engineering
Subject Code/Name : R05220503 – Principles Of Communications
Year : 2008
Degree : B.Tech
Year/Sem : II/II
Website : djriet.edu.in
Document Type : Model Question Paper
Principles Of Communications Supple Aug/Sep 2008: https://www.pdfquestion.in/uploads/djriet.edu.in/2966-R05220503-PRINCIPLES-OF-COMMUNICATIONS.pdf
Principles Of Communications Regular Apr/May 2008 :https://www.pdfquestion.in/uploads/djriet.edu.in/2966–R05220503-PRINCIPLES-OF-COMMUNICATIONS.pdf
Principles Of Communications Question Paper
II B.Tech II Semester Supplimentary Examinations, Aug/Sep 2008 :
PRINCIPLES OF COMMUNICATIONS :
( Common to Computer Science & Engineering, Bio-Medical Engineering, Information Technology, Computer Science & Systems Engineering and Electronics & Computer Engineering)
Time: 3 hours
Max Marks: 80
Answer any FIVE Questions :
Related : Dasari Jhansi Rani Institute Of Engineering And Technology 07A1EC01 C Programming & Data Structures B.Tech Question Paper : www.pdfquestion.in/2989.html
Set – I
All Questions carry equal marks :
1. (a) What are the limitations of Fourier Transform?
(b) State and explain the Dirichlet conditions, in Fourier series. [8+8]
2. In a collector-modulated class C amplifier, the collector dissipation is 60 watts. The amplifier efficiency is 80%. Find the unmodulated carrier power if the depth of modulation is 70%. [16]
3. A carrier is frequency-modulated by a sinusoidal modulating signal of frequency 2 kHz, resulting in a frequency deviation of 5 kHz. What is the bandwidth occupied by the modulated waveform? The amplitude of the modulating sinusoid is increased by a factor of 3 and its frequency lowered to 1 kHz. What is the new bandwidth? [16]
4. Explain the signal recovery through holding. [16]
5. (a) Discuss the performance of adaptive delta modulation compared to that of PCM.
(b) Discuss the limitations of delta-modulation due to fixed step size. [10+6]
6. (a) Differentiate BPSK & QPSK
(b) Define
i. Baud Rate
ii. Matched Filter
iii. Band width efficiency.
iv. SNR. [8+8]
7. (a) Show that for a two dimensional discrete finite probability scheme the joint conditional and marginal entropies are related as
H(x, y) = H(x/y) + H(y)
+H(y/x) + H(x)
Also I(x, y) = H(y) – H(y/x).
(b) An analog signal is band limited to B Hz, sampled at the Niquist rate into 4 levels. The quantization levels Q1, Q2, Q2 and Q4 (messages) are assumed independent and occur with probabilities P1 = P4 = 1/8 and P2 = P3 = 3/8.. Find the information rate of the source. [10+6]
8. (a) Construct the standard array for a (6, 3) linear block code whose generator matrix is given below. G =
1 0 0 1 1 0
0 1 0 0 1 1
0 0 1 1 0 1
(b) Write the advantages of table lookup decoding scheme in linear block codes. [10+6]
Set – II
1. Find the highest value of auto correlation of a function f(t), where f(t) = 2cost + 3cos3t + 4 sin4t. [16]
2. Define amplitude modulation. The rms value of a radio frequency voltage is 200 volts before modulation. When it is modulated by a sinusoidal audio frequency voltage, its rms voltage becomes 242 volts. Calculate the modulation index. [16]
3. A bandwidth rule sometimes used for space communication systems is ß = (2 ß + 1)fm. What fraction of the signal power is included in that frequency band. Consider ß =1 and 10. [16]
4. A function f(t) = sin?ct is sampled at Nyquist rate. If the sampling starts from a zero crossing; can we recover f(t) from its samples? [16]
5. (a) What do you understand by PCM? How quantizing and coding are done?
(b) What is aliasing effect and aperture effect. How these effects can be overcome. [8+8]
6. (a) Differentiate BPSK & QPSK
(b) Define
i. Baud Rate
ii. Matched Filter
iii. Band width efficiency.
iv. SNR. [8+8]
7. (a) What is the significance of coding? Explain the principles of any one type of source code.
(b) Derive expression for channel capacity for infinite bandwidth.
(c) A source is delivering 3 messages with probabilities 1/2, 1/4, 1/4 What is the entropy of second order source. [6+6+4]
8. (a) Construct the standard array for a (6, 3) linear block code whose generator matrix is given below. G =
1 0 0 1 1 0
0 1 0 0 1 1
0 0 1 1 0 1
(b) Write the advantages of table lookup decoding scheme in linear block codes. [10+6]