Code: networkElectronics & Comm. Eng.3rd Semester2 Examination Papers

Network Theory

Official Bihar Engineering University examination question papers, marks distribution, and questions transcript. Available exam sessions: 2023, 2022.

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Official Exam Paper TranscriptB.Tech. 3rd Semester Examination, 2023
Bihar Engineering University, Patna
B.Tech. 3rd Semester Examination, 2023

Network Theory

Time: 03 HoursCode: 104304Full Marks: 70

Instructions:

  1. The marks are indicated in the right-hand margin.
  2. There are NINE questions in this paper.
  3. Attempt FIVE questions in all.
  4. Question No. 1 is compulsory.
Q.1 Choose the correct answer of the following (Any seven question only):[2x7=14]

  1. What is the value of the unit step function u(t−T) at any time tleT

    1. 1
    2. 0
    3. infinite
    4. none of the above

  2. An RC high-pass filter consists of a 820 ohm resistor. What is the value of C is to be taken so that Xc is ten times less than R at an input frequency of 12 kHz?

    1. 81 µF
    2. 161 µF
    3. 161 µF
    4. 220 µF

  3. The transient current in an RLC circuit is oscillating when

    1. R = 2√(L/C)
    2. R = 0
    3. R < 2√(L/C)
    4. R > 2√(L/C)

  4. A cut set matrix gives relation between

    1. Branch currents and link currents
    2. Branch voltages and tree branch voltages
    3. Branch voltages and link voltages
    4. Branch currents and tree currents

  5. A network consists 4 nodes, 6 branches. How many basic loop can be formed?

    1. 3
    2. 9
    3. 1
    4. 2

  6. In a series RLC circuit if C is increased resonant frequency

    1. Increases
    2. Decreases
    3. It remains the same
    4. It is zero

  7. What is the type of filter shown in the figure?

    Question Diagram
    1. Low pass filter
    2. High pass filter
    3. Band pass filter
    4. All pass filter

  8. Comment on the periodicity of a constant signal?

    1. It is periodic
    2. It is not periodic
    3. It is a mixture of period and aperiodic signal
    4. It depends on the signal

  9. The branches which are not present in a tree is called

    1. twigs
    2. links
    3. co-tree
    4. tie-set

  10. A system is linear if it satisfies

    1. Principle of superposition
    2. Principle of homogeneity
    3. Both (i) & (ii)
    4. Only (i)
Q.2 Solve this question :[14]

  1. A given LTI system has produced an impulse response as shown by h(t) given in figure below. Find the time response of this LTI system when an input signal x(t) as shown below is applied to this system.

    Question Diagram
Q.3 Solve both questions :[14]

  1. What is filter? Discuss the advantages of an active filter over a passive filter.

  2. What is band-pass filter? Derive the gain |Vo/Vin| of a first order Butterworth active band-pass filter.

Q.4 Solve both questions :[14]

  1. Explain clearly with the help of suitable examples the following terms used in network analysis:
    a) Oriented graph
    b) Tree
    c) Cut Set
    d) Tie Set
    e) Incidence matrix and its properties.

  2. For a symmetrical two port network prove that AD − BC = 1

Q.5 Solve both questions :[14]

  1. Obtain the first form of the Foster Network for the driving point impedance of LC network given as: Z(S) =[10(S2+4)(S2+16)] / [S(S2+9)]

  2. What is Cauer's form of circuit realization? Describe briefly.

Q.6 Solve this question :[14]

  1. Establish the π− T / Y −Δ transformation relations. Convert the π/Δ into an equivalent T / Y network given below.

    Question Diagram
Q.7 Solve this question :[14]

  1. For the following circuit draw the oriented graph and obtain the Tie-set matrix.

    Question Diagram
Q.8 Solve this question :[14]

  1. In the following circuit Vs= 200√(2)cos500t, R = 80Ω, L = 160 mH.
    (a) Determine the current drawn from Vs and power absorbed by the LR circuit.

    (b) A capacitor is then connected across the Vs, so that the current now drawn from Vs is in phase with Vs. Determine the value of the capacitor and the power drawn from Vs.

    Question Diagram
Q.9 Write short notes on any two of the following:[7x2=14]

  1. Active Band pass filter

  2. Causal & non causal signals with examples

  3. Zero order hold circuit

  4. Aliasing and its effect

Related Official Syllabus

Signal & System

104304

Official BEU curriculum units & topics for this examination subject.

Unit 1.0: Introduction to Signals and Systems

Signals and systems as seen in everyday life, and in various branches of engineering and science • Signal properties: periodicity, absolute integrability, determinism and stochastic character • Some special signals of importance: the unit step, the unit impulse, the sinusoid, the complex exponential, some special time-limited signals • Continuous and discrete time signals • Continuous and discrete amplitude signals • System properties: linearity: additivity and homogeneity, shift-invariance, causality, stability, realizability • Examples

Unit 2.0: Behavior of Continuous and Discrete-Time LTI Systems

Impulse response and step response • Convolution • Input-output behavior with aperiodic convergent inputs • Cascade interconnections • Characterization of causality and stability of LTI systems • System representation through differential equations and difference equations • State space representation of systems • State-Space analysis • Multi-input multi-output representation • State Transition Matrix and its Role • Periodic inputs to an LTI system • The notion of a frequency response and its relation to the impulse response

Unit 3.0: Fourier Series and Fourier Transform

Fourier series representation of periodic signals • Waveform Symmetries • Calculation of Fourier Coefficients • Fourier Transform • Convolution/multiplication and their effect in the frequency domain • Magnitude and phase response • Fourier domain duality • The Discrete-Time Fourier Transform (DTFT) and the Discrete Fourier Transform (DFT) • Parseval's Theorem

Unit 4.0: Laplace Transform

Review of the Laplace Transform for continuous time signals and systems • System functions • Poles and zeros of system functions and signals • Laplace domain analysis • Solution to differential equations and system behavior

Unit 5.0: Sampling and Reconstruction

The Sampling theorem and its implications • Spectra of sampled signals • Reconstruction: ideal interpolator, zero-order hold, first-order hold • Aliasing and its effects • Relation between continuous and discrete time systems • Introduction to the applications of signal and system theory: modulation for communication, filtering, feedback control systems

View Complete 3rd Semester Syllabus

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