Download AKTU B-Tech 2nd Sem 2014-15 EAS 204 Professional Communication Question Paper

Code: 13A05303

B.Tech II Year I Semester (R13) Supplementary Examinations June 2022

SIGNALS AND SYSTEMS

(Common to ECE and EIE)

Time: 3 hours Max. Marks: 70

Answer all five units

All questions carry equal marks

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UNIT – I

1. (a) Explain the properties of the unit impulse function.

   (b) Determine whether the system described by the equation y(t) = x(t)cos(t) is: (i) Static or dynamic (ii) Linear or non-linear (iii) Time-invariant or time-variant (iv) Causal or non-causal

   OR

2. (a) Find whether the signals are energy signals or power signals: (i) x(t) = e^-atu(t), a > 0 (ii) x(t) = Acos(?₀t)

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   (b) Explain the concept of orthogonality in signals.

UNIT – II

1. (a) State and prove the differentiation in time domain property of Fourier Transform.

   (b) Find the Fourier Transform of a gate function of amplitude A and width ‘T’ and sketch its amplitude and phase spectra.

   OR

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2. (a) Explain the significance of Hilbert Transform.

   (b) List the properties of Hilbert Transform.

UNIT – III

1. (a) State and prove sampling theorem for band limited signals.

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   (b) Explain the concept of aliasing.

   OR

2. (a) Explain the concept of signal reconstruction through interpolation.

   (b) List the advantages of digital communication.

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UNIT – IV

1. (a) Determine the convolution of the signals x₁(t) = e^-2tu(t) and x₂(t) = u(t).

   (b) State and prove the properties of convolution.

   OR

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2. (a) Derive the relationship between input and output spectra of an LTI system.

   (b) Explain the properties of an ideal filter.

UNIT – V

1. (a) Define auto correlation and cross correlation.

   (b) Find the auto correlation of x(t) = Acos(?t).

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   OR

2. (a) State and prove the properties of auto correlation function.

   (b) Explain the detection of periodic signals in the presence of noise by correlation.

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