Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Choose the correct option / answer the following (Any seven questions only):
If is the Fourier transform of , then what is the Fourier transform of ?
Which of the following statements is true?
Find the fundamental period of .
If a system's impulse response , the system is:
Which system property ensures that the output depends only on past and present inputs?
Which of the following is an example of a deterministic signal?
The impulse response of an LTI system is given by . Find the system response to an input .
The step response of an LTI system is obtained by:
The Laplace transform of is:
If a signal contains frequency components up to 5 kHz, what should be the minimum sampling rate?
Q.2 Solve both questions :
Find the inverse Laplace transform of:
Given a system with a difference equation , determine its stability.
Q.3 Solve both questions :
Find the state space model of the system represented by the differential equation: .
A system is described by the equation: . Check whether the system is linear or not.
Q.4 Solve both questions :
Compute the poles and zeros of .
Consider a system defined by . Determine whether it is linear and shift-invariant.
Q.5 Solve both questions :
Compute the output of an LTI system with impulse response and input using convolution.
Compute the energy and power of the signal .
Q.6 Solve both questions :
Find the Fourier transform of .
Find the Laplace Transform of and determine its region of convergence.
Q.7 Solve both questions :
Given , determine whether it is periodic and find the fundamental period.
Compute the z-transform of .
Q.8 Solve both questions :
Find the step response of a system with impulse response .
Determine the even and odd components of the signal .
Q.9 Write short notes on any two of the following:
Discuss the properties of a system with respect to linearity, causality, and stability.
Define Fourier series and explain its importance in signal representation.
State and explain the Sampling Theorem and its significance.
State and explain Parseval's Theorem with its application.
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Choose the correct option/answer the following (Any seven questions
only):
If $ X(f) $ is the Fourier transform of $ x(t) $, then what is the Fourier transform of $ x(2t) $?
Which of the following statements is true?
Find the fundamental period of $ x(t) = \sin(5\pi t) + \cos(7\pi t) $.
If a system's impulse response is $ h(t) = \delta(t) + \delta(t-1) $, the system is:
Which system property ensures that the output depends only on past and present inputs?
Which of the following is an example of a deterministic signal?
The impulse response of an LTI system is given by $ h(t) = e^{-2t}u(t) $. Find the system response to an input $ x(t) = e^{-t}u(t) $.
The step response of an LTI system is obtained by:
The Laplace transform of $ e^{-at}u(t) $ is:
If a signal contains frequency components up to 5 kHz, what should be the minimum sampling rate?
Q.2 Solve both questions :
Find the inverse Laplace transform of: $ F(s) = \frac{s(s+2)}{(s+1)(s+3)(s+5)} $.
Given a system with a difference equation $ y[n] - 0.5y[n-1] = x[n] $, determine its stability.
Q.3 Solve both questions :
Find the state space model of the system represented by the differential equation: $ \frac{d^3y}{dt^3} + 8\frac{d^2y}{dt^2} + 9\frac{dy}{dt} = 3x(t) $.
A system is described by the equation: $ y(t) = 3x(t) + 2 $. Check whether the system is linear or not.
Q.4 Solve both questions :
Compute the poles and zeros of $ F(s) = \frac{s+1}{s^3 + 7s^2 + 10s + 18} $.
Consider a system defined by $ y(t) = tx(t) $. Determine whether it is linear and shift-invariant.
Q.5 Solve both questions :
Compute the output $ y[n] $ of an LTI system with impulse response $ h[n] = \{1, 2, 1\} $ and input $ x[n] = \{2, 1, 3\} $ using convolution.
Compute the energy and power of the signal $ x(t) = e^{-t}u(t) $.
Q.6 Solve both questions :
Find the Fourier transform of $ x(t) = e^{-2|t|} $.
Find the Laplace Transform of $ x(t) = e^{-t}u(t) $ and determine its region of convergence.
Q.7 Solve both questions :
Given $ x(t) = \sin(10t) + \cos(15t) $, determine whether it is periodic and find the fundamental period.
Compute the z-transform of $ x[n] = -b^n u[n-1] $.
Q.8 Solve both questions :
Find the step response of a system with impulse response $ h(t) = e^{-3t}u(t) $.
Determine the even and odd components of the signal $ x(t) = t^2 + 3t + 2 $.
Q.9 Write short notes on any two of the following:
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Choose the correct option/answer the following (Any seven questions
only):
If is the Fourier transform of , then what is the Fourier transform of $ x(2t) $?
Which of the following statements is true?
Find the fundamental period of .
If a system's impulse response is , the system is:
Which system property ensures that the output depends only on past and present inputs?
Which of the following is an example of a deterministic signal?
The impulse response of an LTI system is given by . Find the system response to an input .
The step response of an LTI system is obtained by:
The Laplace transform of is:
If a signal contains frequency components up to 5 kHz, what should be the minimum sampling rate?
Q.2 Solve both questions :
Find the inverse Laplace transform of: .
Given a system with a difference equation , determine its stability.
Q.3 Solve both questions :
Find the state space model of the system represented by the differential equation: $ \frac{d^3y}{dt^3} + 8\frac{d^2y}{dt^2} + 9\frac{dy}{dt} = 3x(t) $.
A system is described by the equation: . Check whether the system is linear or not.
Q.4 Solve both questions :
Compute the poles and zeros of .
Consider a system defined by . Determine whether it is linear and shift-invariant.
Q.5 Solve both questions :
Compute the output of an LTI system with impulse response $ h[n] = {1, 2, 1} $ and input using convolution.
Compute the energy and power of the signal .
Q.6 Solve both questions :
Find the Fourier transform of .
Find the Laplace Transform of and determine its region of convergence.
Q.7 Solve both questions :
Given , determine whether it is periodic and find the fundamental period.
Compute the z-transform of .
Q.8 Solve both questions :
Find the step response of a system with impulse response .
Determine the even and odd components of the signal .
Q.9 Write short notes on any two of the following:
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Choose the correct answer of the following (any seven questions
only):
The minimum sampling rate to avoid aliasing for $ x(t) = 5 \cos(400\pi t) $ is:
Which of the following system is memory less?
The ROC of $ x(t) = e^{-2t}u(t) + e^{-3t}u(t) $ is:
Time period of: $ x(t) = 3 \cos(20t+5) + \sin(8t-3) $ is:
The power of the signal: $ x(t) = \cos(t) $ is:
The Fourier transform exponential signal $ f(t) = e^{-at}u(t), a > 0 $ is:
$ x(5t) $ is:
Which one of the following is an example of a bounded signal?
The simplified valve of $ X(n) = \sum_{n=-5}^{5} \sin(2n)\delta(n+7) $ is:
If $ X(S) = \frac{4S+1}{S^2+6S+3} $, then initial value of $ x(0) $ will be:
Q.2 Solve both questions :
Find the inverse Z-transform of $ X(Z) = \frac{1}{1+3Z^{-1}+2Z^{-2}} $, $ ROC: |Z| > 2 $.
For the system $ y(t) = 12x(t) + 7 $, check whether the system is (i) time variant/time-invariant (ii) causal/non-causal (iii) linear/non-linear.
Q.3 Solve both questions :
Find the even and odd components of the sequence $ X(n) = 5\delta(n+4) + 4\delta(n+3) + 3\delta(n+2) + \delta(n+1) $.
Determine the power of the signal $ x(t) = e^{j\alpha t}\cos(\omega_o t) $.
Q.4 Solve both questions :
Find the Fourier transform of $ x(t) = \frac{1}{a^2+t^2} $.
Find the time response of LTI system with impulse response $ h(t) = 2u(t) - 2u(t-3) $ & input is $ x(t) = 8u(t) - 8u(t-5) $.
Q.5 Solve both questions :
Sketch the signal $ x(-4t-3) $ as shown in figure.

Find the convolution of the following sequence $ x(n) = 2\delta(n+1) - \delta(n) + \delta(n-1) + 3\delta(n-2) $ and $ h(n) = 3\delta(n-1) + 4\delta(n-2) + 2\delta(n-3) $.
Q.6 Solve both questions :
Compute the DFT of $ x(n) = \{0, 1, 2, 4\} $.
Compute the output of the following signals whose impulse response and input are given by $ h(t) = e^{-at}u(t) $; $ x(t) = e^{at}u(-t), a>0 $ respectively.
Q.7 Solve both questions :
Find the Laplace Transform of signal in the figure.

Calculate the fundamental period of $ x(t) = 1 + \sin(\frac{2\pi}{3}t)\cos(\frac{4\pi}{5}t) $.
Q.8 Solve both questions :
Determine the Nyquist sampling rate and Nyquist sampling intervals for the signal $ x(t) = \text{sinc}(100\pi t)\text{sinc}(200\pi t) $.
Compute the state transition matrix $ \Phi(t) $ for the system represented by state equation: $ \begin{bmatrix} \dot{x}_1 \\ \dot{x}_2 \end{bmatrix} = \begin{bmatrix} 0 & 1 \\ -2 & 0 \end{bmatrix} \begin{bmatrix} x_1 \\ x_2 \end{bmatrix} $.
Q.9 Write short notes on any two of the following:
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Choose the correct answer of the following (any seven questions
only):
The minimum sampling rate to avoid aliasing for $ x(t) = 5 \cos(400\pi t) $ is:
Which of the following system is memory less?
The ROC of $ x(t) = e^{-2t}u(t) + e^{-3t}u(t) $ is:
Time period of: $ x(t) = 3 \cos(20t+5) + \sin(8t-3) $ is:
The power of the signal: $ x(t) = \cos(t) $ is:
The Fourier transform exponential signal $ f(t) = e^{-at}u(t), a > 0 $ is:
$ x(5t) $ is:
Which one of the following is an example of a bounded signal?
The simplified valve of $ X(n) = \sum_{n=-5}^{5} \sin(2n)\delta(n+7) $ is:
If $ X(S) = \frac{4S+1}{S^2+6S+3} $, then initial value of $ x(0) $ will be:
Q.2 Solve both questions :
Find the inverse Z-transform of $ X(Z) = \frac{1}{1+3Z^{-1}+2Z^{-2}} $, $ ROC: |Z| > 2 $.
For the system $ y(t) = 12x(t) + 7 $, check whether the system is (i) time variant/time-invariant (ii) causal/non-causal (iii) linear/non-linear.
Q.3 Solve both questions :
Find the even and odd components of the sequence $ X(n) = 5\delta(n+4) + 4\delta(n+3) + 3\delta(n+2) + \delta(n+1) $.
Determine the power of the signal $ x(t) = e^{j\alpha t}\cos(\omega_o t) $.
Q.4 Solve both questions :
Find the Fourier transform of $ x(t) = \frac{1}{a^2+t^2} $.
Find the time response of LTI system with impulse response $ h(t) = 2u(t) - 2u(t-3) $ & input is $ x(t) = 8u(t) - 8u(t-5) $.
Q.5 Solve both questions :
Sketch the signal $ x(-4t-3) $ as shown in figure.

Find the convolution of the following sequence $ x(n) = 2\delta(n+1) - \delta(n) + \delta(n-1) + 3\delta(n-2) $ and $ h(n) = 3\delta(n-1) + 4\delta(n-2) + 2\delta(n-3) $.
Q.6 Solve both questions :
Compute the DFT of $ x(n) = \\{0, 1, 2, 4\\} $.
Compute the output of the following signals whose impulse response and input are given by $ h(t) = e^{-at}u(t) $; $ x(t) = e^{at}u(-t), a>0 $ respectively.
Q.7 Solve both questions :
Find the Laplace Transform of signal in the figure.

Calculate the fundamental period of $ x(t) = 1 + \sin(\frac{2\pi}{3}t)\cos(\frac{4\pi}{5}t) $.
Q.8 Solve both questions :
Determine the Nyquist sampling rate and Nyquist sampling intervals for the signal $ x(t) = \text{sinc}(100\pi t)\text{sinc}(200\pi t) $.
Compute the state transition matrix $ \Phi(t) $ for the system represented by state equation: $ \begin{bmatrix} \dot{x}_1 \\ \dot{x}_2 \end{bmatrix} = \begin{bmatrix} 0 & 1 \\ -2 & 0 \end{bmatrix} \begin{bmatrix} x_1 \\ x_2 \end{bmatrix} $.
Q.9 Write short notes on any two of the following:
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Answer any seven of the following as directed:
Determine the fundamental period of the signal $ x[n]=1+e^{j\frac{4\pi n}{7}}-e^{j\frac{2\pi n}{5}} $
Check whether the signal $ x(t)=2e^{j(t+\frac{\pi}{4})}u(t) $ is periodic or not. If periodic, then compute the periodicity.
Find the convolution of two signals $ x_{1}(t)=e^{-t^{2}} $ and $ x_{2}(t)=3t^{2} $
Let $ X(e^{j\omega}) $ be the DTFT of $ x[n] $ prove that $ X(e^{j0})=\sum_{n=-\infty}^{\infty}x[n] $
The step response of an LTI system when the impulse response $ h(n) $ is unit step $ u(n) $ is _________.
Use the convolution property of Laplace transform to determine $ y(t)=e^{at}u(t)*e^{bt}u(t) $ where symbols have their usual meanings.
Determine the Laplace transform of the signal $ x(t)=\cos^{3}(3t)u(t) $.
If $ X(z)\leftarrow\underline{z}\rightarrow x[n] $ with ROC: R, then prove that $ Z\{x[-n]\}=X(z^{-1}) $ with ROC: $ \frac{1}{R} $
List down the properties of region of convergence (ROC).
Determine the conditions on the sampling interval $ T_{s} $ so that $ x(t)=\cos(\pi t)+3\sin(2\pi t)+\sin(4\pi t) $ is uniquely represented by the discrete-time sequence $ x[n]=x(nT_{s}) $
Q.2 Solve all questions :
Consider a causal LTI system that is represented by the difference equation $ y[n]-\frac{3}{4}y[n-1]+\frac{1}{8}y[n-2]=2x[n] $. Find the frequency response $ H(e^{j\omega}) $ and the impulse response $ h[n] $ of the system.
Find the inverse DTFT of $ X(e^{j\omega})=\delta(\omega), -\pi < \omega < \pi $
Find the Fourier transform of $ x(n)=a^{|n|}, |a|< 1 $
Q.3 Solve all questions :
Find the Z-transform of $ x(n)=\begin{cases}(0.5)^{n}u(n),&n>0\\ (0.25)^{-n},&n < 0\end{cases} $
Find the inverse Z-transform of $ X(z)=\frac{1-\frac{1}{4}z^{-1}}{1-\frac{1}{9}z^{-1}} $ ROC: $ |z|>\frac{1}{3} $
Comment on the causality of the system whose transfer function is given by $ H(z)=\frac{3-4z^{-1}}{1-3.5z^{-1}+1.5z^{-2}}, |z|>3 $
Q.4 Solve all questions :
Derive the condition for BIBO stability.
Consider a continuous-time system with input $ x(t) $ and output $ y(t) $ is related by $ y(t)=x(\sin(t)) $. Is the system (i) causal and (ii) linear?
Sketch the signal $ x(t)=\delta(\cos t) $.
Find even and odd components of signal $ x(t)=e^{-2t}\cos(t) $.
Q.5 Solve all questions :
Compute the Fourier transform of the rectangular pulse train signal shown in Fig. 1.

Compute the step response of the LTI system $ H(s)=\frac{6(s+1)}{s(s+3)}; Re\{s\}>0 $
State and prove Parseval's theorem.
Q.6 Solve all questions :
A system is defined as $ y(n)=x(n^{2}) $. Check whether the system is linear or non-linear, time-varying or time-invariant, causal or non-causal and memory less or memory type.
Compute the convolution $ y[n]=x[n]*h[n] $ where $ x[n]=u(n-1) $ and $ h[n]=\alpha^{n}u(n-1) $
Compute the Nyquist sampling rate for the signal $ g(t)=10\cos(50\pi)\cos^{2}(150\pi t) $
Q.7 Solve all questions :
Consider the causal difference equation $ y[n]-0.8y[n-1]=2x[n] $ where the input signal is $ x[n]=(\frac{1}{2})^{n}u(n) $ with $ y[-1]=0 $. Find the output response $ y[n] $.
Compute the inverse Z-transform of $ X(z)=\frac{z}{(1-0.5z^{-1})}; |z|<0.5 $ using the power series expansion method. Find the signal $ x[n] $.
Consider the stable LTI system defined by its transfer function $ H(z)=\frac{z^{2}+z-2}{z^{2}+z+0.5} $. Sketch the pole-zero plot for this transfer function and give its ROC. Is the system causal? Sketch the direct form realization of this system.
Q.8 Solve all questions :
Let $ x[n] $ be an arbitrary function with even and odd parts as $ x_{e}[n] $, $ x_{o}[n] $, respectively. Show that $ \sum_{n=-\infty}^{\infty}x^{2}[n]=\sum_{n=-\infty}^{\infty}x_{e}^{2}[n]+\sum_{n=-\infty}^{\infty}x_{o}^{2}[n] $
Perform the convolution operation between $ x[n]=\{0,0,0,0,(2),-3,1,0,0\} $ and $ h[n]=\{0,0,0,1,(2),2,0,0,0\} $ using graphical method.
The signal $ x(t) $ is shown in Fig. 2. Sketch the signals for $ \alpha=\frac{1}{2} $ and $ \alpha=2 $.

Q.9 Write short notes on any four of the following:
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Answer any seven of the following as directed:
Determine the fundamental period of the signal $ x[n]=1+e^{j\frac{4\pi n}{7}}-e^{j\frac{2\pi n}{5}} $
Check whether the signal $ x(t)=2e^{j(t+\frac{\pi}{4})}u(t) $ is periodic or not. If periodic, then compute the periodicity.
Find the convolution of two signals $ x_{1}(t)=e^{-t^{2}} $ and $ x_{2}(t)=3t^{2} $
Let $ X(e^{j\omega}) $ be the DTFT of $ x[n] $ prove that $ X(e^{j0})=\sum_{n=-\infty}^{\infty}x[n] $
The step response of an LTI system when the impulse response $ h(n) $ is unit step $ u(n) $ is _________.
Use the convolution property of Laplace transform to determine $ y(t)=e^{at}u(t)*e^{bt}u(t) $ where symbols have their usual meanings.
Determine the Laplace transform of the signal $ x(t)=\cos^{3}(3t)u(t) $.
If $ X(z)\leftarrow\underline{z}\rightarrow x[n] $ with ROC: R, then prove that $ Z\\{x[-n]\\}=X(z^{-1}) $ with ROC: $ \frac{1}{R} $
List down the properties of region of convergence (ROC).
Determine the conditions on the sampling interval $ T_{s} $ so that $ x(t)=\cos(\pi t)+3\sin(2\pi t)+\sin(4\pi t) $ is uniquely represented by the discrete-time sequence $ x[n]=x(nT_{s}) $
Q.2 Solve all questions :
Consider a causal LTI system that is represented by the difference equation $ y[n]-\frac{3}{4}y[n-1]+\frac{1}{8}y[n-2]=2x[n] $. Find the frequency response $ H(e^{j\omega}) $ and the impulse response $ h[n] $ of the system.
Find the inverse DTFT of $ X(e^{j\omega})=\delta(\omega), -\pi < \omega < \pi $
Find the Fourier transform of $ x(n)=a^{|n|}, |a|< 1 $
Q.3 Solve all questions :
Find the Z-transform of $ x(n)=\begin{cases}(0.5)^{n}u(n),&n>0\\ (0.25)^{-n},&n < 0\end{cases} $
Find the inverse Z-transform of $ X(z)=\frac{1-\frac{1}{4}z^{-1}}{1-\frac{1}{9}z^{-1}} $ ROC: $ |z|>\frac{1}{3} $
Comment on the causality of the system whose transfer function is given by $ H(z)=\frac{3-4z^{-1}}{1-3.5z^{-1}+1.5z^{-2}}, |z|>3 $
Q.4 Solve all questions :
Derive the condition for BIBO stability.
Consider a continuous-time system with input $ x(t) $ and output $ y(t) $ is related by $ y(t)=x(\sin(t)) $. Is the system (i) causal and (ii) linear?
Sketch the signal $ x(t)=\delta(\cos t) $.
Find even and odd components of signal $ x(t)=e^{-2t}\cos(t) $.
Q.5 Solve all questions :
Compute the Fourier transform of the rectangular pulse train signal shown in Fig. 1.

Compute the step response of the LTI system $ H(s)=\frac{6(s+1)}{s(s+3)}; Re\\{s\\}>0 $
State and prove Parseval's theorem.
Q.6 Solve all questions :
A system is defined as $ y(n)=x(n^{2}) $. Check whether the system is linear or non-linear, time-varying or time-invariant, causal or non-causal and memory less or memory type.
Compute the convolution $ y[n]=x[n]*h[n] $ where $ x[n]=u(n-1) $ and $ h[n]=\alpha^{n}u(n-1) $
Compute the Nyquist sampling rate for the signal $ g(t)=10\cos(50\pi)\cos^{2}(150\pi t) $
Q.7 Solve all questions :
Consider the causal difference equation $ y[n]-0.8y[n-1]=2x[n] $ where the input signal is $ x[n]=(\frac{1}{2})^{n}u(n) $ with $ y[-1]=0 $. Find the output response $ y[n] $.
Compute the inverse Z-transform of $ X(z)=\frac{z}{(1-0.5z^{-1})}; |z|<0.5 $ using the power series expansion method. Find the signal $ x[n] $.
Consider the stable LTI system defined by its transfer function $ H(z)=\frac{z^{2}+z-2}{z^{2}+z+0.5} $. Sketch the pole-zero plot for this transfer function and give its ROC. Is the system causal? Sketch the direct form realization of this system.
Q.8 Solve all questions :
Let $ x[n] $ be an arbitrary function with even and odd parts as $ x_{e}[n] $, $ x_{o}[n] $, respectively. Show that $ \sum_{n=-\infty}^{\infty}x^{2}[n]=\sum_{n=-\infty}^{\infty}x_{e}^{2}[n]+\sum_{n=-\infty}^{\infty}x_{o}^{2}[n] $
Perform the convolution operation between $ x[n]=\\{0,0,0,0,(2),-3,1,0,0\\} $ and $ h[n]=\\{0,0,0,1,(2),2,0,0,0\\} $ using graphical method.
The signal $ x(t) $ is shown in Fig. 2. Sketch the signals for $ \alpha=\frac{1}{2} $ and $ \alpha=2 $.

Q.9 Write short notes on any four of the following:
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Section 1
Answer any seven of the following as directed :
Determine the fundamental period of the signal $x[n] = 1 + e^{j \frac{4\pi n}{7}} - e^{j \frac{2\pi n}{5}}$
Check whether the signal $x(t) = 2e^{j(t + \frac{\pi}{4})} u(t)$ is periodic or not. If periodic, then compute the periodicity.
Find the convolution of two signals and
Let be the DTFT of , prove that $X(e^{j0}) = \sum_{n=-\infty}^\infty x[n]$
The step response of an LTI system when the impulse response is unit step is ______.
Use the convolution property of Laplace transform to determine $y(t) = e^{at} u(t) * e^{bt} u(t)$ where symbols have their usual meanings.
Determine the Laplace transform of the signal .
If with ROC : , then prove that $Z{x[-n]} = X(z^{-1})$ with ROC : .
List down the properties of region of convergence (ROC).
Determine the conditions on the sampling interval so that $x(t) = \cos(\pi t) + 3\sin(2\pi t) + \sin(4\pi t)$ is uniquely represented by the discrete-time sequence .
Section 2
Consider a causal LTI system that is represented by the difference equation $y[n] - \frac{3}{4}y[n-1] + \frac{1}{8}y[n-2] = 2x[n]$ Find the frequency response and the impulse response of the system.
Find the inverse DTFT of .
Find the Fourier transform of .
Find the Z-transform of $x(n) = \begin{cases} (0.5)^n u(n), & n > 0 \ (0.25)^{-n}, & n < 0 \end{cases}$
Find the inverse Z-transform of ROC :
Comment on the causality of the system whose transfer function is given by $H(z) = \frac{3 - 4z^{-1}}{1 - 3.5z^{-1} + 1.5z^{-2}}, |z| > 3$
Derive the condition for BIBO stability.
Consider a continuous-time system with input and output is related by . Is the system (i) causal and (ii) linear?
Sketch the signal .
Find even and odd components of signal .
Compute the Fourier transform of the signal (periodic rectangular pulse train) shown in Fig. 1.
Compute the step response of the LTI system $H(s) = \frac{6(s+1)}{s(s+3)}; $\text{Re}\{s\} > 0
State and prove Parseval's theorem.
A system is defined as . Check whether the system is linear or non-linear, time-varying or time-invariant, causal or non-causal and memory less or memory type.
Compute the convolution where and .
Compute the Nyquist sampling rate for the signal .
Consider the causal difference equation where the input signal is with . Find the output response .
Compute the inverse Z-transform of . Find the signal using the power series expansion method.
Consider the stable LTI system defined by its transfer function $H(z) = \frac{z^2 + z - 2}{z^2 + z + 0.5}$. Sketch the pole-zero plot for this transfer function and give its ROC. Is the system causal? Sketch the direct form realization of this system.
Let be an arbitrary function with even and odd parts as , respectively. Show that $\sum_{n=-\infty}^\infty x^2[n] = \sum_{n=-\infty}^\infty x_e^2[n] + \sum_{n=-\infty}^\infty x_o^2[n]$
Perform the convolution operation between and using graphical method.
The signal is shown in Fig. 2. Sketch the signals for and (assuming the task is to sketch $x(\alpha t)$).
Write short notes on any four of the following :
Power and energy signals
Relationship between Laplace and Z-transform
Initial and Final value theorems
Properties of Fourier transform
Zero-order hold circuit
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Answer the following as directed (any seven):
If the Z-transform of $ x(n) $ is $ X(z) $ then show that $ Z[x_{1}(n)*x_{2}(n)]=X_{1}(z)X_{2}(z) $
If the impulse response for a system is given by $ h(n)=a^{n}u(n) $, then what is the condition for the system to be BIBO stable?
A voltage having the laplace transform $ \frac{4s^{2}+3s+2}{7s^{2}+6s+5} $ is applied across a 2H inductor. What is the current in inductor at $ t \to \infty $ assuming zero initial condition?
Differentiate between Kronecker delta function and Direc delta function.
The step response of an LTI system when the impulse response $ h(n) $ is unit step $ u(n) $ is _________.
Find the Laplace transform $ f(t)=e^{3t}\cos(2t)u(t) $ where symbols have their usual meanings.
An LTI system is described as $ 0.5\frac{d^{2}y(t)}{dt^{2}}+2.5\frac{dy(t)}{dt}+2y(t)=\delta(t) $. Find the final value of the output response where $ y(t) $ is output and $ x(t) $ is input.
The period of a sequence $ x(n)=\cos(\frac{2\pi n}{3}) $ is _________.
The final value of step response of a causal LTI system with $ H(s)=\frac{s+1}{s+4} $ is
Consider two functions $ f(t)=h(t)h(3-t) $ and $ g(t)=h(t)-h(t-3) $. Are these two functions identical? Show that $ L[f(t)]=L[g(t)] $ where L is the Laplace operator.
Q.2 Solve all questions :
Let a system is described by the differential equation as $ \ddot{y}+3\dot{y}+2y=e^{-t} $; with initial condition $ y(0)=\dot{y}(0)=0 $. Compute the solution of the equation.
Let $ f(t) $ is a periodic function with periodicity T for $ t\ge0 $, then show that $ L[f(t)]=\frac{L[f_{T}(t)]}{1-e^{-sT}} $, $ s>0 $
Find the Laplace transform of Fig. 1.

Q.3 Solve all questions :
State why ROC does not include any pole. Find the Z-transform of $ x(n)=\begin{cases}(0.5)^{n}u(n),&n>0\\ (0.25)^{-n},&n < 0\end{cases} $
Find the inverse Z-transform of $ X(z)=\frac{1-\frac{1}{4}z^{-1}}{1-\frac{1}{9}z^{-1}} $ where ROC: $ |z|>\frac{1}{3} $
Show that $ Z[nx(n)]=-z\frac{dX(z)}{dz} $ where $ X(z)\leftrightarrow x[n] $.
Q.4 Solve all questions :
Briefly explain the causality of a system.
Find whether the signal $ x[n]=\sin(\frac{3\pi}{4}n)+\sin(\frac{\pi}{3}n) $ is periodic or aperiodic. If periodic, then what is the periodicity of x[n]?
Write down the Dirichlet condition.
Find the Fourier transform of $ x(t)=e^{-|t|}u(t) $, and hence draw the magnitude and phase spectrums.
Q.5 Solve all questions :
Compute the Fourier transform of signal shown in Fig. 2: $ R_{x}(\tau)=\begin{cases}\frac{N}{2},&-B\le\tau\le B\\ 0,&elsewhere\end{cases} $

Find the convolution of the following discrete sequences: $ x(n)=\frac{1}{3}u(n) $ and $ h(n)=\frac{1}{5}u(n) $
State why the realization of an ideal low-pass filter is not possible, with proper justification.
Q.6 Solve all questions :
A system is defined as $ y(n)=x(n^{2}) $. Check whether the system is linear or non-linear, time-varying or time-invariant, causal or non-causal, and memoryless or memory type.
State Parseval's theorem.
Sketch the signal $ x(t)=-2u(t-1) $.
Compute the Nyquist sampling rate for the signal $ g(t)=10\cos(50\pi)\cos^{2}(150\pi t) $
Q.7 Solve all questions :
Show that $ u(n)=\sum_{k=-\infty}^{n}\delta(n) $ where symbols have their usual meanings.
What is unit doublet? Prove that $ \int_{-\infty}^{\infty}x(t)\delta^{k}(t)dt=(-1)^{k}\frac{d^{k}x(t)}{dt^{k}}|_{t=0} $ where $ x^{k} $ is k-th derivative of function $ x(t) $ and $ \delta(t) $ is Dirac delta function.
A system is described by its input-output relationship as $ y[n]=\sum_{k=-\infty}^{n}x[n-k] $. Is the system memoryless, stable, causal, time-invariant and linear?
Find the fundamental period of signal $ x[n]=e^{j7.351\pi n} $
Q.8 Solve all questions :
Let $ x[n] $ be an arbitrary function with even and odd part as $ x_{e}[n] $ and $ x_{o}[n] $ respectively. Show that $ \sum_{n=-\infty}^{\infty}x^{2}[n]=\sum_{n=-\infty}^{\infty}x_{e}^{2}[n]+\sum_{n=-\infty}^{\infty}x_{o}^{2}[n] $
Perform the convolution operation between $ x[n]=\{0,0,0,0,(2),-3,1,0,0\} $ and $ h[n]=\{0,0,0,1,(2),2,0,0,0\} $ using graphical method.
Calculate the Fourier transform of $ x[n]=u[n] $.
Q.9 Write short notes on any four of the following:
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Answer the following as directed (any seven):
If the Z-transform of $ x(n) $ is $ X(z) $ then show that $ Z[x_{1}(n)*x_{2}(n)]=X_{1}(z)X_{2}(z) $
If the impulse response for a system is given by $ h(n)=a^{n}u(n) $, then what is the condition for the system to be BIBO stable?
A voltage having the laplace transform $ \frac{4s^{2}+3s+2}{7s^{2}+6s+5} $ is applied across a 2H inductor. What is the current in inductor at $ t \to \infty $ assuming zero initial condition?
Differentiate between Kronecker delta function and Direc delta function.
The step response of an LTI system when the impulse response $ h(n) $ is unit step $ u(n) $ is _________.
Find the Laplace transform $ f(t)=e^{3t}\cos(2t)u(t) $ where symbols have their usual meanings.
An LTI system is described as $ 0.5\frac{d^{2}y(t)}{dt^{2}}+2.5\frac{dy(t)}{dt}+2y(t)=\delta(t) $. Find the final value of the output response where $ y(t) $ is output and $ x(t) $ is input.
The period of a sequence $ x(n)=\cos(\frac{2\pi n}{3}) $ is _________.
The final value of step response of a causal LTI system with $ H(s)=\frac{s+1}{s+4} $ is
Consider two functions $ f(t)=h(t)h(3-t) $ and $ g(t)=h(t)-h(t-3) $. Are these two functions identical? Show that $ L[f(t)]=L[g(t)] $ where L is the Laplace operator.
Q.2 Solve all questions :
Let a system is described by the differential equation as $ \ddot{y}+3\dot{y}+2y=e^{-t} $; with initial condition $ y(0)=\dot{y}(0)=0 $. Compute the solution of the equation.
Let $ f(t) $ is a periodic function with periodicity T for $ t\ge0 $, then show that $ L[f(t)]=\frac{L[f_{T}(t)]}{1-e^{-sT}} $, $ s>0 $
Find the Laplace transform of Fig. 1.

Q.3 Solve all questions :
State why ROC does not include any pole. Find the Z-transform of $ x(n)=\begin{cases}(0.5)^{n}u(n),&n>0\\ (0.25)^{-n},&n < 0\end{cases} $
Find the inverse Z-transform of $ X(z)=\frac{1-\frac{1}{4}z^{-1}}{1-\frac{1}{9}z^{-1}} $ where ROC: $ |z|>\frac{1}{3} $
Show that $ Z[nx(n)]=-z\frac{dX(z)}{dz} $ where $ X(z)\leftrightarrow x[n] $.
Q.4 Solve all questions :
Briefly explain the causality of a system.
Find whether the signal $ x[n]=\sin(\frac{3\pi}{4}n)+\sin(\frac{\pi}{3}n) $ is periodic or aperiodic. If periodic, then what is the periodicity of x[n]?
Write down the Dirichlet condition.
Find the Fourier transform of $ x(t)=e^{-|t|}u(t) $, and hence draw the magnitude and phase spectrums.
Q.5 Solve all questions :
Compute the Fourier transform of signal shown in Fig. 2: $ R_{x}(\tau)=\begin{cases}\frac{N}{2},&-B\le\tau\le B\\ 0,&elsewhere\end{cases} $

Find the convolution of the following discrete sequences: $ x(n)=\frac{1}{3}u(n) $ and $ h(n)=\frac{1}{5}u(n) $
State why the realization of an ideal low-pass filter is not possible, with proper justification.
Q.6 Solve all questions :
A system is defined as $ y(n)=x(n^{2}) $. Check whether the system is linear or non-linear, time-varying or time-invariant, causal or non-causal, and memoryless or memory type.
State Parseval's theorem.
Sketch the signal $ x(t)=-2u(t-1) $.
Compute the Nyquist sampling rate for the signal $ g(t)=10\cos(50\pi)\cos^{2}(150\pi t) $
Q.7 Solve all questions :
Show that $ u(n)=\sum_{k=-\infty}^{n}\delta(n) $ where symbols have their usual meanings.
What is unit doublet? Prove that $ \int_{-\infty}^{\infty}x(t)\delta^{k}(t)dt=(-1)^{k}\frac{d^{k}x(t)}{dt^{k}}|_{t=0} $ where $ x^{k} $ is k-th derivative of function $ x(t) $ and $ \delta(t) $ is Dirac delta function.
A system is described by its input-output relationship as $ y[n]=\sum_{k=-\infty}^{n}x[n-k] $. Is the system memoryless, stable, causal, time-invariant and linear?
Find the fundamental period of signal $ x[n]=e^{j7.351\pi n} $
Q.8 Solve all questions :
Let $ x[n] $ be an arbitrary function with even and odd part as $ x_{e}[n] $ and $ x_{o}[n] $ respectively. Show that $ \sum_{n=-\infty}^{\infty}x^{2}[n]=\sum_{n=-\infty}^{\infty}x_{e}^{2}[n]+\sum_{n=-\infty}^{\infty}x_{o}^{2}[n] $
Perform the convolution operation between $ x[n]=\\{0,0,0,0,(2),-3,1,0,0\\} $ and $ h[n]=\\{0,0,0,1,(2),2,0,0,0\\} $ using graphical method.
Calculate the Fourier transform of $ x[n]=u[n] $.
Q.9 Write short notes on any four of the following:
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Answer any seven of the following questions:
Find the fundamental period and frequency of the signal $ x(t)=\cos 18\pi t+\sin 12\pi t $
With an example, prove that cascade combination of an LTI system and its inverse system results an identity system.
Check whether the system $ y(t)=tx(t) $ is causal and stable.
What is the physical significance of convolution?
What do you mean by convergence of Fourier series?
Prove that $ x_{even}(t)\leftrightarrow Re\{a_{k}\} $ where $ x(t) $ is real and $ x(t)\leftrightarrow a_{k} $.
Determine the Laplace transform for the signal $ x(t)=e^{-5t}u(t-1) $.
For an LTI system to be causal and stable, what should be the condition on ROC and locations of poles?
Find the z-transform and ROC of $ x[n]=(\frac{1}{5})^{n}u(n-3) $
State and prove time reversal property of z-transform.
Q.2 Solve both questions :
Compute and plot the even and odd parts of the given discrete and continuous signals from the figures.

Let $ x(t)=u(t-3)-u(t-5) $ and $ h(t)=e^{-3t}u(t) $. Compute:
(i) $ y(t)=x(t)*h(t) $
(ii) $ g(t)=(dx(t)/dt)*h(t) $
Q.3 Solve both questions :
For each of the following systems, check the properties of linearity, time-invariance, causality
and BIBO stability:
(i) $ y(t)=x(t/2) $
(ii) $ y[n]=nx[n] $
Compute and plot the convolution $ y[n]=x[n]*h[n] $ where $ x[n]=(\frac{1}{2})^{n-2}u[n-2] $ and $ h[n]=u[n+2] $.
Q.4 Solve both questions :
Obtain the differential equations for the given systems.

Explain the 'property of sifting' of discrete-time unit impulse.
Q.5 Solve both questions :
State and prove the following properties of continuous-time Fourier series:
(i) Frequency shifting
(ii) Periodic convolution in time-domain
(iii) Time scaling
(iv) Differentiation in time-domain
Calculate the Fourier series coefficients for the periodic signal
$ x(t)=\begin{cases}2&,&0\le t< 2\\ -2,&2\le t< 4\end{cases} $
with fundamental frequency $ \omega_{0}=\pi/2 $.
Q.6 Solve both questions :
State and prove the following properties of discrete-time Fourier transform:
(i) Time shifting
(ii) Time expansion
(iii) Multiplication of two signals in time-domain
(iv) Differentiation in frequency
Compute the Fourier transform of $ x[n]=(\frac{1}{4})^{|n-1|} $.
Q.7 Solve both questions :
Consider an LTI system whose response to the input $ x(t)=(e^{-t}+e^{-3t})u(t) $ is $ y(t)=(2e^{-t}-2e^{-4t})u(t) $. Using Laplace transforms, find the impulse response of the system. Also compute its frequency response.
Determine the inverse Laplace transform of $ X(s)=\frac{(s+1)}{(s+1)^{2}+4} $, $ Re\{s\}>-1 $.
Q.8 Solve both questions :
Determine the impulse response of the system described by the difference equation $ y[n]=\frac{1}{2}[x[n]+x[n-1]+y[n-1]] $. Assume that the system is initially relaxed.
Solve the following linear difference equation:
$ y[n]+\frac{1}{2}y[n-1]-\frac{1}{4}y[n-2]=0 $
Given that $ y[-1]=y[-2]=1 $.
Q.9 Solve both questions :
Determine all possible signals of $ x(n) $ associated with the following z-transforms:
(i) $ X(z)=\frac{1}{1-\frac{3}{2}z^{-1}+\frac{1}{2}z^{-2}} $
(ii) $ X(z)=\frac{5}{1-\frac{1}{2}z^{-1}+\frac{1}{4}z^{-2}} $
Obtain the z-transform and ROC of the following sequence:
$ x(n)=(\frac{1}{2})^{n}[u[n]-u[n-10]] $
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Q.1 Answer any seven of the following questions:
Find the fundamental period and frequency of the signal $ x(t)=\cos 18\pi t+\sin 12\pi t $
With an example, prove that cascade combination of an LTI system and its inverse system results an identity system.
Check whether the system $ y(t)=tx(t) $ is causal and stable.
What is the physical significance of convolution?
What do you mean by convergence of Fourier series?
Prove that $ x_{even}(t)\leftrightarrow Re\{a_{k}\} $ where $ x(t) $ is real and $ x(t)\leftrightarrow a_{k} $.
Determine the Laplace transform for the signal $ x(t)=e^{-5t}u(t-1) $.
For an LTI system to be causal and stable, what should be the condition on ROC and locations of poles?
Find the z-transform and ROC of $ x[n]=(\frac{1}{5})^{n}u(n-3) $
State and prove time reversal property of z-transform.
Q.2 Solve both questions :
Compute and plot the even and odd parts of the given discrete and continuous signals from the figures.

Let $ x(t)=u(t-3)-u(t-5) $ and $ h(t)=e^{-3t}u(t) $. Compute:
(i) $ y(t)=x(t)*h(t) $
(ii) $ g(t)=(dx(t)/dt)*h(t) $
Q.3 Solve both questions :
For each of the following systems, check the properties of linearity, time-invariance, causality
and BIBO stability:
(i) $ y(t)=x(t/2) $
(ii) $ y[n]=nx[n] $
Compute and plot the convolution $ y[n]=x[n]*h[n] $ where $ x[n]=(\frac{1}{2})^{n-2}u[n-2] $ and $ h[n]=u[n+2] $.
Q.4 Solve both questions :
Obtain the differential equations for the given systems.

Explain the 'property of sifting' of discrete-time unit impulse.
Q.5 Solve both questions :
State and prove the following properties of continuous-time Fourier series:
(i) Frequency shifting
(ii) Periodic convolution in time-domain
(iii) Time scaling
(iv) Differentiation in time-domain
Calculate the Fourier series coefficients for the periodic signal
$ x(t)=\begin{cases}2&,&0\le t< 2\\ -2,&2\le t< 4\end{cases} $
with fundamental frequency $ \omega_{0}=\pi/2 $.
Q.6 Solve both questions :
State and prove the following properties of discrete-time Fourier transform:
(i) Time shifting
(ii) Time expansion
(iii) Multiplication of two signals in time-domain
(iv) Differentiation in frequency
Compute the Fourier transform of $ x[n]=(\frac{1}{4})^{|n-1|} $.
Q.7 Solve both questions :
Consider an LTI system whose response to the input $ x(t)=(e^{-t}+e^{-3t})u(t) $ is $ y(t)=(2e^{-t}-2e^{-4t})u(t) $. Using Laplace transforms, find the impulse response of the system. Also compute its frequency response.
Determine the inverse Laplace transform of $ X(s)=\frac{(s+1)}{(s+1)^{2}+4} $, $ Re\{s\}>-1 $.
Q.8 Solve both questions :
Determine the impulse response of the system described by the difference equation $ y[n]=\frac{1}{2}[x[n]+x[n-1]+y[n-1]] $. Assume that the system is initially relaxed.
Solve the following linear difference equation:
$ y[n]+\frac{1}{2}y[n-1]-\frac{1}{4}y[n-2]=0 $
Given that $ y[-1]=y[-2]=1 $.
Q.9 Solve both questions :
Determine all possible signals of $ x(n) $ associated with the following z-transforms:
(i) $ X(z)=\frac{1}{1-\frac{3}{2}z^{-1}+\frac{1}{2}z^{-2}} $
(ii) $ X(z)=\frac{5}{1-\frac{1}{2}z^{-1}+\frac{1}{4}z^{-2}} $
Obtain the z-transform and ROC of the following sequence:
$ x(n)=(\frac{1}{2})^{n}[u[n]-u[n-10]] $
Instructions:
- The marks are indicated in the right-hand margin.
- There are EIGHT questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Section 1
Answer any seven questions of the following :
Show where is an impulse function.
Prove that
Draw the time waveform of the signal
Determine the fundamental period of the signal .
If is the energy of the signal , determine the energy of the signal in terms of .
If and are odd and even signals respectively, determine whether the signal would be even or odd signal.
Determine whether the system described by is causal.
A system is described by the input-output relationship . Determine whether the corresponding system is linear, where represents the real part of .
Determine whether the system described by is stable or not.
Sketch the time waveform of the signal
Section 2
Determine convolution of a rectangular signal with itself. is described as $x(t) = \begin{cases} A & -T < t < T \ 0 & \text{otherwise} \end{cases}$ Draw the sketch of the convolved signal.
Prove that
Prove that .
Determine the overall impulse response of the system shown in the figure below : [Diagram: Cascade connection of two systems with impulse responses and $h_2(n)$] where and .
Evaluate the unit step response of the LTI system represented by
The impulse response of a system is given by . Determine whether this system is causal.
From the given Fourier series derive the relation to determine the Fourier series coefficients . Given is periodic with period .
Determine the Fourier series coefficients of the following : $x(t) = 1 + \sin \omega_0 t + 2\cos \omega_0 t + \cos(2\omega_0 t + \pi/4)$
Prove the following properties of the Fourier series :
Time shifting
Time reversal
Multiplication
Determine the Fourier transform of the following signals :
,
Determine the inverse Fourier transform of
Prove that the Fourier transform of a real and even signal is real and even.
Given that has Fourier transform . Using Fourier transform properties or otherwise, determine the Fourier transform of the following signals :
Prove the following properties of discrete-time Fourier transform :
Conjugation
Differentiation in frequency
Convolution
If the input to an LTI system is then the output is . Determine the system function of this system. Comment on the stability of the system.
Given determine the signal when
ROC
ROC
ROC
Determine the z-transform of the following signals. Sketch their pole-zero plot and indicate the region of convergence :
Consider an even sequence with rational z-transform . From the definition of z-transform, show that .
Determine the system function for the causal LTI system with difference equation and also determine its impulse response.
Instructions:
- The marks are indicated in the right-hand margin.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Section 1
Choose the correct answer (any seven) :
Let denote the delta function. The value of the integral is
If a signal has energy , the energy of signal is equal to
The system is
The system represented by is
The impulse response of a system is . If two such systems are cascaded, the impulse response of the overall system will be
If is odd, then its Fourier series coefficients must be
The Laplace transform of a unit ramp function starting at is
If , then and are given by
If the impulse response of a discrete time system is , then the system function is equal to
The output of discrete LTI system is always identical to the input signal, when the unit impulse response is
Section 2
For the signal shown in the figure below, find the signals (i) , (ii) , (iii) and (iv) :
Find whether the following signals are periodic or not : (i) (ii) (iii) (iv) (v) (vi)
Check whether the following systems are linear or not : (i) (ii) (iii) (iv) (v) (vi) (vii)
For each of the following systems, determine whether the system is time-invariant : (i) (ii) (iii) (iv) (v) (vi) (vii) (viii)
Prove that the output of a discrete time system can be represented as a weighted sum of shifted impulse responses.
Obtain the convolution of the following sequence : ,
Obtain the differential equations governing the following systems :
A mechanical translational system consisting of a mass , a spring with constant , and a damper with constant , with a force applied and displacement indicated.
A series RLC circuit with resistor , inductor , and capacitor driven by a voltage source .
An electrical network with a resistor, a inductor, and a capacitor, with input voltage and output .
Find cosine Fourier series of half-wave rectified sine function.
For the waveform shown in the figure below (a periodic rectangular pulse train), find the Laplace transform.
For the waveform shown in the figure below (a single triangular pulse), find the Laplace transform.
Using Laplace transform, solve the following differential equation : $\frac{d^3y(t)}{dt^3} + 7\frac{d^2y(t)}{dt^2} + 16\frac{dy(t)}{dt} + 12y(t) = x(t)$ if \frac{dy(0^-)}{dt} = 0$; $\frac{d^2y(0^-)}{dt^2} = 0, and
Find the impulse response and step response for the following system : $y(n) - \frac{3}{4}y(n-1) + \frac{1}{8}y(n-2) = x(n)$
Instructions:
- All questions carry equal marks.
- There are NINE questions in this paper.
- Attempt FIVE questions in all.
- Question No. 1 is compulsory.
Section 1
Answer any seven of the following questions :
Define causal system.
What is continuous time signal?
Write the condition of existence for Laplace transform.
Define Fourier transform of a sequence.
What is DTFT pair?
What is Fourier integral?
What are analogous systems?
Find the z-transform of discrete-time unit impulse .
What is z-transform of ?
Define region of convergence (ROC).
Section 2
Sketch the following signal : for Also determine whether the given signal is a power signal or an energy signal or neither.
Show that a system with excitation and response described by is linear, time-variant, non-causal.
Compare energy and power signals.
What are the elementary signals? Explain with suitable diagrams.
Compare force-voltage analogy with force-current analogy.
Obtain the solution of the differential equation given below using Laplace transform : $2 \frac{dx}{dt} + 8x = 10$ Given .
The Laplace transform of is given by $F(s) = \frac{4}{s(s+2)}$ Find the final value using the final-value theorem and verify the result by determining using inverse Laplace transform.
Find the inverse Fourier transform of .
Write the Dirichlet's conditions for Fourier series.
Obtain Fourier series representation of the periodic rectangular waveform which is defined as $x(t) = \begin{cases} 0 & \text{for } t \in (-T/2, -T/4) \ A & \text{for } t \in (-T/4, T/4) \ 0 & \text{for } t \in (T/4, T/2) \end{cases}$
Explain the concept of negative frequency. Find the Fourier transform of the everlasting sinusoid .
Explain the linearity and time-scaling properties of Fourier transform.
Discuss the classification of turbines based on head.
Define specific speed. What are different types of turbine based on specific speed?
A hydroelectric station is to be supplied with of water through a penstock which has a friction factor of 0.016. The maximum normal head on the penstock is and a water hammer over pressure of 20% is anticipated over normal pressure. The safe stress in the steel used is presumed to be . The ready penstocks at site are likely to cost ₹ 65000 per tonne including erection charges. The life of the project is 50 years and the rate of interest is 7%. It is proposed to sell the energy at the rate of ₹ 3.03 per kWh. What should be the optimum diameter of the penstock, given that the OMR costs 5%? Assume the turbine efficiency to be 90% and the annual load factor as 0.4.