# Digital Signal Processing Important Quetions: Mid-1

1 Feb 2016    07:37 pm

UNIT – I

PART-A:

(1).Define DSP and give the Merits, Demerits and Applications?

(2).Justify whether the following system is Time-Invariant or not

(i).y(n)=sin(x(n)) (ii).y(n)=2x(n-1)+5

(3).Justify the stability of the system whose Impulse Response is h(n)=(1/2)ⁿ u(n).

(4).List the various Applications of Z-Transform?

(5).Design the Flow Graph of Linear Phase FIR System?

(6).Design the Flow Graph of a Realization of IIR System for Cascade and Parallel Form

PART-B:

(1).Solve the following difference equation

(a).y(n)=0.7y(n-1)-0.1y(n-2)+2x(n)-x(n-2),the input x(n) is the Unit Sample

(b).y(n)-4y(n-1)+4y(n-2)=x(n)-x(n-1),input is x(n)=(-1)ⁿ u(n) and initial conditions

y(-1)=y(-2)=1

(2).(a).Find the Impulse Response and Frequency Response of the filter defined

by  y(n)=x(n)+by(n-1)

(b).The Impulse Response of a LTI system is given by h(n)=(0.6)ⁿ u(n).Find the

Frequency Response.

(3).(a).Find the response for the following system

y(n)-y(n-1)+6y(n-2)=x(n)where x(n)=n

(b).A LTI system is described by the following difference equation,

y(n)=ay(n-1)+bx(n).Find the Impulse Response, Magnitude function and

Phase function.

(4).(a).Find the Impulse Response of the system described by the difference

equation y(n)-3y(n-1)-4y(n-2)=x(n)+2x(n-1) using Z-Transform

(b).An LTI system is described by the equation

y(n)=x(n)+0.81x(n-1)-0.81x(n-2)-0.45y(n-2).Determine Transfer function and

sketch the Poles and Zeros on the Z-plane.

(5).(a).Find the Frequency Response, Magnitude Response and Phase Response

For the system given by, y(n)-(3/4)y(n-1)+(1/8)y(n-2)=x(n)-x(n-1)

(b).The Impulse Response of an LTI system is given by h(n)=(r)ⁿ cos(wOn)u(n).Find

the Frequency Response of the system.

(6).(a).Design Direct Form-I & II IIR Realization Structures in detail with necessary

Flow Graphs.

(b).Find the digital network in Direct and Transposed form for the system

described by the difference equation

y(n)=x(n)+0.5x(n-1)+0.4x(n-2)-0.6y(n-1)-0.7y(n-2)

UNIT – 2

PART-A:

(1).Define the DFS Representation of periodic Sequences?

(2).List and explain the Properties of DFS?

(3).List and explain the Properties of DFT?

(4).Define FFT? Calculate the number of multiplications needed in the calculation of

DFT using FFT Algorithm with 32- point sequence.

(5).Comparison between Radix-2 DIT-FFT and DIF-FFT Algorithms?

(6).Sketch the basic Butterfly Structure for Radix-2 DIT-FFT and DIF-FFT

Algorithms?

PART-B:

(1). (a).Compute the 8-Point DFT of the sequence x(n)={1,1,1,1,1,1,0,0}

(b).Compute the IDFT of the sequence X(K)={5,0,1-j,0,1,0,1+j,0}

(2).Compute the Linear Convolution of the following two sequences using DFT& IDFT

(i).x(n)={2,1,2,1} and h(n)={1,2,3,4} (ii).x(n)={1,0.5,0} and h(n)={0.5,1}

(3).Find the output y(n) of a filter whose Impulse Response is h(n)={1,2} and input

x(n)={1,2,-1,2,3,-2,-3,-1,1,1,2,-1} by using (i).Overlap-Add method (ii).Overlap-

Save method.

(4).An 8-Point sequence is given by x(n)={2,2,2,2,1,1,1,1}.Compute 8-Point DFT of

x(n) by (i).Radx-2 DIT-FFT Algorithm (ii). Radx-2 DIF-FFT Algorithm

(5).Design the Butterfly line Diagram for 8-Point FFT calculation and briefly explain

using (i).Radx-2 DIT-FFT Algorithm (ii). Radx-2 DIF-FFT Algorithm

(6). ).An 8-Point sequence is given by X(K)={4,0,0,0,4,0,0,0}.Compute 8-Point IDFT of

X(K) by (i).Radx-2 DIT-FFT Algorithm (ii). Radx-2 DIF-FFT Algorithm

UNIT – 3

PART-A:

(1).How one can design digital filters from Analog Filters?

(2).Find the order of the LPF for Butterworth Approximation, for 3dB

attenuation at 500Hz and an attenuation of 40dB at 1000Hz.

(3).Realize the system with difference equation,

y(n)=(3/4)y(n-1)-(1/8)y(n-2)+x(n)+(1/3)x(n-1) in Cascade Form.

PART-B:

(1).(a)Compare Butterworth and Chebyshev Filters

(b).Find the order of LPF if it has pass band attenuation of -3dB a at

800rad/sec and stop band attenuation of -10dB at 1800rad/sec

(2).Design and Explain the Analog Filter using Butterworth Approximation

(3).Design and Explain the Analog Filter using Chebyshev Approximation  