UNIT I
16 MARK QUESTIONS
1. Explain the block Diagram and Quantization process of PCM system in detail. (APRIL/MAY
2007)
2. Derive the expression for sampling process and the reconstruction of original signals in time
domain? (MAY 2008)
3. Explain about bandpass sampling in detail.
3. Explain the generation of PAM signals and its power spectrum? (MAY 2008)
4. Explain briefly about the effects of under sampling? (NOV 2005)
6. Explain DM and ADM with suitable waveforms? (APRIL//MAY 2008)
7. Derive the expression for quantization noise and signal to noise ratio in PCM?
8. Explain in detail about TDM? (NOV/DEC 2004)
9. Explain in detail about DPCM.
UNIT II
1. Describe the conditions for zero ISI based on sampling theorem.
2. Elaborate on the concept and characteristics of correlative coding.
3. Explain the following with necessary figures and expression
• Raised cosine channels.
• Adaptive equalization for data transmission.
4. Draw the Eye pattern and explain its parts
5. Draw and explain the block diagram of Delta modulation
6. What are the different types of quantizer?
7. Explain the concept of companding.
UNIT III
1. With necessary equations and signal space diagram, obtain the probability of error for coherent binary FSK
systems. (MAY’2005)
2. Draw the block diagram of QPSK and obtain the probability of error. (MAY’2007)
3. With necessary equations and signal space diagram, obtain the probability of error for coherent binary MSK
systems.
4. Explain BPSK signal transmission and coherent BPSK reception with suitable diagrams. Derive an expression for
the probability of symbol error for the scheme.(MAY’2006,NOV’2008)
5. With neat block diagram, explain briefly how symbol synchronization is achieved? (MAY’2009)
6.Explain about Correlation receivers and matched filters in detail.
7.Compare the Signal Space diagram for various modulation techniques.
UNIT IV
1. Explain coherent binary PSK with the help of transmitter & receiver.
2. Explain coherent binary FSK with the help of transmitter & receiver.
3. Derive the expression for probability of error in coherent FSK
4. Explain the properties of matched filter.
5. Explain the concept of matched filter.
6. Derive the expression for probability of error in QPSK
7. Draw the signal space diagram for QPSK and find Euclidean distance.
8. Derive the expression for probability of error in coherent BPSK
9. Explain the difference between correlator and matched filter.
10. Draw the block diagram of DPSK system. Explain the working by means of suitable diagram
11. Write short note on QPSK.
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UNIT V
Explain the difference between convolution codes and block codes.
A rate 1/3 convolution code is described by; g1=[1 0 1], g2=[1 0 0],g3=[1 1 1]
i.
Draw the encoder corresponding to this code
ii.
Draw code trellis diagram.
iii.
Draw state diagram for this code.
iv.
O/P of demodulator detector is (101001011110111),using viterbi algorithm, find surviving path.
A rate 1/3 convolution code is described by; g1=[1 1 1], g2=[1 0 0],g3=[1 0 1]
Draw the encoder & code tree corresponding to this code.
What is constraint length of convolution code.
A rate 2/3 convolution code is described by; g1=[1 0 1 1, g2=[1 1 0 1], g3=[1 0 1 0] Draw the encoder
,code tree ,code trellis & state diagram corresponding to this code
A convolutional code is described by g1=[1 0 0], g2=[1 0 1],g3=[1 1 1] Find the advance transfer function
and the free distance of this code
Write short note on Sequential decoding
Write short note on viterbi decoding
A rate 2/3 convolution code is described by; g1=[1 0 1 1, g2=[1 1 0 1],
g3=[1 0 1 0] . O/P of
demodulator detector is (01011111110111),using viterbi algorithm, find surviving path.
A convolutional code is described by g1=[1 0 1], g2=[1 0 0],g3=[1 1 1] Find the advance transfer function
and the free distance of this code
Explain free distance & coding gain
Give advantages of convolution code
State and prove the properties of syndrome decoding (MAY’2006)
2. Consider a rate 1/3, non-systematic convolutional code with, g(1)(p)={1,0,1}, g(2)={1,1,1}. Determine
the encoder output corresponding to the data sequence {1,0,1,0,1}. If the first and the fourth bits of the
encoded sequence are affected during transmission, demonstrate the error correcting capability of the
viterbi algorithm. (NOV’2005)
3. A (15,5) linear cyclic code has a generator polynomial,
g(D)=1+D+D2+D4+D5+D8+D10
Draw block diagrams of an encoder and syndrome calculator for this code. Find the code
polynomial in systematic form, for the message polynomial m(D)=1+D2+D4. Is
y(D)=1+D4+D6+D8+D14, a code polynomial? If not, find the syndrome of y(D). (NOV’2008)
4. Briefly explain the viterbi decoding algorithm.
5. Draw the diagram of the . rate convolutional encoder with generator polynomials g(1)(D)=1+D and
g(2)(D)=1+D+D2. And compute the encoder output for input sequence 101101. (NOV’2009)
6. Explain any four characteristics of the following block codes (i) BCH
codes (ii) CRC codes (iii) maximum length codes.
7. Explain the syndrome ‘S’ for all five probable single error patterns in
(5,1) repetition code. (JUNE’2006)
8. Generate the code words for (7, 4) Hamming code.
9. Describe the design procedure for linear block code.