STUPIDSID
1(a)
Explain sampling theorem of low pass signals and derive the interpolation formula.
8 M
1(b)
A low pass signal x(t) has spectrum X(f) given by,
X(f)=\left\{\begin{matrix} 1-\dfrac{\left | f \right |}{200} ;& |f|<200\\ \\ 0 & \text {Elsewhere} \end{matrix}\right.
Sketch the spectrum Xδ(f) for |f| <200Hz if x(t) is ideally sampled at fδ = 45 Hz. Indicate if and how the signal can be recovered. Image:
X(f)=\left\{\begin{matrix} 1-\dfrac{\left | f \right |}{200} ;& |f|<200\\ \\ 0 & \text {Elsewhere} \end{matrix}\right.
Sketch the spectrum Xδ(f) for |f| <200Hz if x(t) is ideally sampled at fδ = 45 Hz. Indicate if and how the signal can be recovered. Image:
6 M
2(a)
Derive the expression for signal to quantization noise ratio (SNR) and show that for uniform quantization, each bit in the codeworld of a PCM contributes 6 dB to SNR.
8 M
2(b)
For a binary PCM signal, determine L if the compression parameter μ = 100 and the minimum [SNR]0 dB= 45 dB. Determine the [SNR]0 dB with this value of L.
6 M
2(c)
With a neat block diagram and waveform, explain time division multiplexing.
6 M
3(a)
Explain the principles of delta modulator. With relevant figure and mathematical expressions, explain the functioning of DM transmitter and receiver.
8 M
3(b)
For a binary sequence 111000110101 draw the digital format waveforms corresponding to:
i) Bipolar NRZ waveform and ii) 8-ary signaling waveform.
i) Bipolar NRZ waveform and ii) 8-ary signaling waveform.
6 M
3(c)
Derive an expression for power spectral density of bipolar NRZ format and plot the same with respect to frequency.
6 M
4(a)
What is correlative coding? Explain duo binary coding with and without precoding.
8 M
4(b)
The binary data 011100101 are applied to the input of a modified duo binary system:
i) Construct the modified duo binary coder output and corresponding receiver output without a precoder.
ii) Suppose that due to error in transmission, the level produced by the third digit is reduced to zero. Construct a new receiver output.
i) Construct the modified duo binary coder output and corresponding receiver output without a precoder.
ii) Suppose that due to error in transmission, the level produced by the third digit is reduced to zero. Construct a new receiver output.
7 M
4(c)
With a neat block diagram, explain the concept of adaptive equalization
5 M
5(a)
With neat block diagram, explain DPSK transmitter and receiver. Illustrate the generation of deferentially encoded sequence for the binary input sequence 00100110011110.
12 M
5(b)
A binary data is transmitted over an AWGN channel using binary phase shift keying at the rate of 1 Mbps. It is desired to have average probability of error Pe ≤10-4. Noise power spectral density is N0/2 = 10-12 W/HZ. Determine the average carrier power required at the receiver input, if the detector is of coherent type. Take erfc(3.5) = 0.00025.
8 M
6(a)
Write a note on Gram-Schmidt orthogonalization procedure.
8 M
6(b)
Consider the signal s1(t), s2(t), s3(t) and s4(t) as given below in Fig.Q6(b). Image:
Find an orthonormal basis for these set of signals using Gram-Schmidt orthogonalization procedure.
Find an orthonormal basis for these set of signals using Gram-Schmidt orthogonalization procedure.
12 M
7(a)
Draw and explain the block diagram of correlation receiver.
8 M
7(b)
Show that the probality of bit error of a matched filter receiver is given by \[P_{e}=\dfrac{1}{2}erfc\sqrt{\dfrac{E_{b}}N_{0}}\]
12 M
8(a)
What is spread spectrum technique? How are they classified?
8 M
8(b)
Explain properties of PN sequence.
6 M
8(c)
A slow FH/MFSK system has the following parameters:
The number of bits/ MFSK symobl = 4
The number of MFSK symbols per hop =6
Calculate processing gain of the system.
The number of bits/ MFSK symobl = 4
The number of MFSK symbols per hop =6
Calculate processing gain of the system.
8 M
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