STUPIDSID
1 (a)
Compare BASK, BFSK &BPSK based on following parameters: bandwidth requirement, noise immunity, efficiency & applications.
4 M
1 (b)
State and explain Shannon's theorem for channel capacity.
4 M
1 (c)
Explain a decoding scheme which prevents error propagation in a duo-binary system.
4 M
1 (d)
Differentiate between MSK and offset QPSK.
4 M
1 (e)
Draw signal constellation diagram for 16-ary QASK and find its Euclidean Distance.
4 M
2 (a)
Explain the significance ISI in digital communication system. How is it caused? How it can be avoided? Derive the expression for Nyquist's condition for Distortion-less transmission.
10 M
2 (b)
A discrete memory less source has in alphabets of fine symbol with their probabilities as shown below:
i) Construct Huffman Code for each symbol and determine following parameters: Entropy, Average Code word length, Code Efficiency and Code Redundancy.
ii) Determine the above parameters for Shannon-Fano Code.
| Symbol | S1 | S2 | S3 | S4 | S5 |
| Probability | 0.15 | 0.11 | 0.19 | 0.40 | 0.15 |
i) Construct Huffman Code for each symbol and determine following parameters: Entropy, Average Code word length, Code Efficiency and Code Redundancy.
ii) Determine the above parameters for Shannon-Fano Code.
10 M
3 (a)
The Generator vectors for a convolution encoder with code rate 1/3 are g1=110, g2=101, g3=111.
i) Draw Encoder diagram and determine code word for input vector (10111)
ii) Draw trellis diagram and state diagram.
i) Draw Encoder diagram and determine code word for input vector (10111)
ii) Draw trellis diagram and state diagram.
10 M
3 (b)
Justify that MS is a frequency shift keying with relevant expressions.
5 M
3 (c)
Explain the working of Matched filter in communication receiver.
5 M
4 (a)
if a data bit sequence is 101100111010, draw (i) offset and non offset QPSK waveforms, (ii) BFSK waveform.
6 M
4 (b)
Write the mathematical expression of DPSK transmitted signal and explain DPSK transmitter and receiver. Draw the DPSK waveform for the sequence given in 4(a).
8 M
4 (c)
Explain Duo binary encoder-decoder. Show how the given sequence 1100101001 is recovered at the receiver.
6 M
5 (a)
A (7,4) cyclic code is generated using the polynomial g(x)=(1+x+x3)
i) Generate the systematic cyclic code for the data 1001 and 1010(MSB) by long division method.
ii) Draw the encoder & show how codewords are generated for the same data given above, by tracing the path through the encoder and verify the result.
i) Generate the systematic cyclic code for the data 1001 and 1010(MSB) by long division method.
ii) Draw the encoder & show how codewords are generated for the same data given above, by tracing the path through the encoder and verify the result.
10 M
5 (b)
With respect to 8-ary PSK, explain the following:
i) block diagram of transmitter and receiver
ii) Mathematical expression of the transmitted signal
iii) Sketch its PSD and indicate its bandwidth
iv) Draw its signal space diagram and find is Euclidean distance.
i) block diagram of transmitter and receiver
ii) Mathematical expression of the transmitted signal
iii) Sketch its PSD and indicate its bandwidth
iv) Draw its signal space diagram and find is Euclidean distance.
10 M
6 (a)
What is spread spectrum modulation? Bring out the significance of PN Sequence. Explain Direct sequence Spread Spectrum, DS-BPSK. Write the expression for Processing gain and Jamming Margin.
10 M
6 (b)
With a neat diagram, explain the working of Integrate and Dump Receiver. Derive the expression for its probability of error.
10 M
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