STUPIDSID
1 (a)
Explain natural sampling with relevant waveforms. Give all the necessary time-domain and frequency-domain equations.
10 M
1 (b)
What is aliasing error? Give two corrective measures to remove the effect of aliasing in practice.
4 M
1 (c)
Consider the analog signal x(t)=5cos(2000Πt)+10cos(6000Πt).
i) What is the Nyquist rate and Nyquist interval?
ii) Assume that if we sample the signal using sampling frequency fs=5000 Hz, what is the resulting discrete time signal obtained after sampling?
iii) Draw the spectrum of the sampled signal.
i) What is the Nyquist rate and Nyquist interval?
ii) Assume that if we sample the signal using sampling frequency fs=5000 Hz, what is the resulting discrete time signal obtained after sampling?
iii) Draw the spectrum of the sampled signal.
6 M
2 (a)
Explain regenerative repeater in a PCM system with a block diagram.
5 M
2 (b)
The bandwidth of a signal is 3.4 KHz. If this signal is converted to PCM bit stream with 1024 levels, determine the number of bits per second (bps) generated by the PCM system. Assume that the signal is sampled at the rate of 20% above the Nyquist rate.
6 M
2 (c)
Derive an expression for the output SNR of a uniform quantizer the SNR is (SNR)output=6n-7.2 dB, where 'n' is the number of bits per sample. Assume a loading factors of 4.
9 M
3 (a)
Explain with block diagrams DPCM transmitter and receiver.
9 M
3 (b)
Explain briefly the basic optical fibre link used for the transmission of digital data.
6 M
3 (c)
Show that for the bipolar format, the autocorrelation function Rs(n), that is E(AkAK-n) is zero for n>1, where AK is the Kth random variable representing Kth bit of the input binary sequence. Assume statistically independent and equally likely message bits.
5 M
4 (a)
Explain raised cosine spectrum solution to reduce ISI.
10 M
4 (b)
The binary data 0011011001 are applied to the input of the dou-binary system.
i) Construct the duo-binary coder output and the corresponding receiver output without a pre-coder.
ii) Suppose that due to error during transmission, the level at the receiver input produced by the second digit is reduced to zero. Construct the new receiver output.
i) Construct the duo-binary coder output and the corresponding receiver output without a pre-coder.
ii) Suppose that due to error during transmission, the level at the receiver input produced by the second digit is reduced to zero. Construct the new receiver output.
10 M
5 (a)
Explain the generation and demodulation of DPSK wave with block diagrams.
8 M
5 (b)
Binary data are transmitted over a microwave link at the rate of 106 bps and the PSD of the noise at the receiver inputs is 10-10 Watts per hertz. Find the average carrier power required to maintain an average probability of error Pe?10-4 for coherent binary FSK. What is the required channel band width? (Take erfc (2.7)=2×10-4).
6 M
5 (c)
Explain briefly phase tree and phase Trellis in MSK.
6 M
6 (a)
What is a signal vector? Show that the energy of a signal is equal to the squared length of the signal vector representing it.
8 M
6 (b)
Explain the Gram-Schmidt orthogonalization procedure to obtain the orthonormal basis functions for the linearly independent set of signals.
12 M
7 (a)
Show that the output SNR of a method filter is proportional to the ratio of the signal energy to the PSD of input noise.
6 M
7 (b)
Explain the non coherent quadrature receiver using correlators.
6 M
7 (c)
Consider the signal s(t) as shown in the Fig. Q7(c). Determine the impulse response of the filter matched to s(t). Plot the impulse response and matched filter output as a function of time.
8 M
8 (a)
Define processing gain and jamming margin.
4 M
8 (b)
What is the role of PN sequence in spread spectrum communication? For the given PN sequence 0011101 verify the properties of it.
8 M
8 (c)
Discuss briefly the applications of spread spectrum technique to (i) CDMA, (ii) Multipath suppression.
8 M
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