# SRM University 2007 B.Tech Information Technology BANK : Principles of Communication - Question Paper

Wednesday, 30 January 2013 06:35Web

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S.R.M. Institute of Science & Technology

School of Electronics & Communication Engineering

ques. BANK

Subject Code : EC215

Subject Name : Principles of Communication

Year & Semester : II Year III Sem ( for IT)

Unit-I - INTRODUCTION

**Part-A**

**1.**What is the need for modulation?

**2.**describe

**a)**Energy signal

**b)**Power signal

**3.**describe

**a)**Odd & Even signal

**b)**Deterministic and Random Signal

**4.**describe

**a)**Periodic

**b)**Aperiodic signal

**5.**Determine the power of the signal x(t)=C cos (?0t +0)

**6.**Determine the energy of x(t)=e-5tu(t)

**7.**What is meant by internal noise and external noise

**8.**Check for the Causality

**a)**y(t)=x(t

**2)**

**b)**y(t)=x(t)+5 x(t)

**9.**Check for time invariant and variant

**a)**y(t)=t x(t)

**b)**y(t)=x(t)-x(t-1)

**10.**describe Energy spectral density and Power spectral density

**1**describe Auto-correlation and Cross-correlation.

**1.****1**provide 2 properties of Power Spectral density

**2.****1**provide 2 properties of auto-correlation function of energy signals

**3.****1**What is sampling theorem

**4.****1**What is aliasing

**5.****1**What is Hilbert Transform

**6.****1**write the properties of Hilbert transform

**7.****1**State Parsevalâ€™s theorem

**8.****1**What is Fourier series.Give the trigonometric form of Fourier series an also provide the Dirichlets Conditions

**9.****20.**obtain the frequency spectrum of a rectangular pulse shown in fig and provided by the

formul

**a.**F(t) = V , -t /2 < t < t /2

0 , otherwise

f(t)

V

-? /2 0 ? / two

**2**What is an Impulse signal.Give its function.

**1.****2**describe System and provide their classification.

**2.****2**describe causal and time invariant system

**3.****Part-B**

1. With the help of a neat sketch, discuss the block diagram of a communication system.

2. Explain in detail about the signal classifications

3. Give short notes on channel characteristics

4. Explain in detail about Hilbert transform

5. Explain in detail, about the system classifications

6. Check for LTI system

**a)**y(t)=10 x(t) +5

**b)**y(t)=x(t2)

7. Calculate the FT of

**a)**Decaying exponential pulse x(t)=exp(-t)u(t) b)rectangular pulse x(t) is provided by

X(t)

t

8. Explain in detail about the energy spectral density and Power spectral density

9. Obtain the FT of the impulse function

10. Obtain the FT of a triangular pulse

Earning: Approval pending. |