STUPIDSID
1 (a)
Explain briefly Nyquist's sampling theorem. What is Interpolation process?
Derive Interpolation formula.
7 M
1 (b)
What is probability density function? State and prove its properties.
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2 (a)
A television signal has a bandwidth of 4.5 MHz. This signal is sampled,
quantized and binary coded to obtain a PCM signal.
(a)Determine the sampling rate if the signal is to be sampled at a rate 20%
above the Nyquist rate. (b) If the samples are quantized into 1024 levels,
determine the number of binary pulses required to encode each sample. (c)
Determine the binary pulse rate (bits per second) of the binary-coded signal,
and the minimum bandwidth required to transmit this signal.
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2 (b)
Draw and explain block diagram of ADPCM system. Compare PCM and
ADPCM.
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2 (c)
Why pulse shaping is required? What is Inter Symbol Interference? Explain
Nyquist's first criterion for zero ISI.
7 M
3 (a)
Derive the general expression for PSD of a large class of line codes.
7 M
3 (b)
Define mean, variance and standard deviation of the random variable. Find
mean square and variance of the uniform quantization error whose pdf is
\[\begin{align*}P_{q}(q)&=L/2m_{p}\ for\ -m_{p}/L\le q\le m_{p}/L\\ &=0\ \ \ \ \ \ \ \ \ \ \ otherwise\end{align*}\]
where L is quantization level and (-m ,mp ) is signal amplitudes range.
\[\begin{align*}P_{q}(q)&=L/2m_{p}\ for\ -m_{p}/L\le q\le m_{p}/L\\ &=0\ \ \ \ \ \ \ \ \ \ \ otherwise\end{align*}\]
where L is quantization level and (-m
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3 (c)
A source emits seven massages with probabilities 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, and 1/64, respectively. Find the entropy of the source. Obtain the compact binary code and find the average length of the code word. Determine the
efficiency and the redundancy of the code.
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3 (d)
What is scrambling? Explain scrambling and descrambling process with block
diagram and suitable example.
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4 (a)
Derive the equation for channel capacity of discrete memoryless channel.
7 M
4 (b)
Find the generator matrix G for a (15,11) single error correcting systematic
linear block code. Find the code word for the data vector 10111010101.
7 M
4 (c)
Define entropy. Prove that entropy is maximum when all the messages are
Equiprobable.
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4 (d)
A generator matrix \[G=\begin{bmatrix}
1 &0 &1 &1 \\0
&1 &1 &0
\end{bmatrix}\] generates a (4,2) code.(a) Is this a systematic code? (b) What is the parity check matrix of this code? (c) Find the codewords for all possible input bits. (d) Determine the minimum distance of the code and the number of bit errors this code can correct.
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5 (a)
Explain Quadrature Phase Shift Keying (QPSK) technique with neat sketch.
Draw constellation diagram for QPSK.
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5 (b)
Derive expressions for impulse response and probability of errror of Matched filter.
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5 (c)
What are the different types of spread spectrum system? Draw and explain block diagram of frequency hopping spread spetrum (FHSS) system.
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5 (d)
Explain convolution coding in brief.
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