# Dr. A.P.J. Abdul Kalam University BE VI SEM (EC) Digital Signal Processing [EC603] June 2021 Question Paper

Dr. A.P.J. Abdul Kalam University

Bachelor of Engineering

Sixth Semester Examination, June-2021

Digital Signal Processing [EC603]

Branch-EC

Time: 3:00 Hrs Max Marks 70

Note: Attempt any five questions. All questions carry equal marks.

Q.1 (a) What are discrete time signals and system? What do you mean by linearity

and time invariance of these systems?

(b) Draw and explain the flow graph for decimation in frequency FFT algorithm

for N=8 show various stages of decimation.

Q.2 (a) Discuss decimation in time algorithm for FFT and how it differs from the

decimation in frequency algorithm

(b) Prove the properties of time shifting and time reversal are applicable to ztransform

Q.3 (a) Draw the flow graph for decimation in time FFT algorithm for N=8, using

radix 2. Show various steps of decimation.

(b) Describe and explain Bilinear transformation method for designing digital

filters

Q.4 (a) Discuss radix of FFT algorithm. Find the number of computations required

for 1024 point DFT using normal methods.

(b) Define DFT of a given time sequence x(n) and hence write five different

properties of DFT by giving suitable illustrations

Q.5 (a) Derive the equation for the convolution sum as applicable to DTLTI system.

(b) Explain window technique for designing FIR digital filter.

Q.6 (a) How DFT can be used to perform high speed convolution? Explain by giving

example.

(b) Write down the characteristic of Bilinear transformation.

Q.7 a) What are the desirable and undesirable features of FIR filters? Differentiate

between FIR filters and IIR filters.

b) Show that multiplication of two DFT’s is a circular convolution in time

domain. Dropped call rate formula.

Q.8. State and prove the following properties of DFT.

(i) Even and odd properties (ii) Circular frequency shift

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