JNTU
JNTU B.Tech III DIGITAL SIGNAL PROCESSING Previous Question Paper (December - 2018 - R15)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks and may have a, b, c as sub questions.
PART - A
What are the properties of frequency response H(e^jω) of an LTI system?
Answer
The frequency response H(e^jω) is a periodic function of ω with a period of 2π. Additionally, for a real-valued impulse response h(n), the magnitude response |H(e^jω)| is an even function of ω, and the phase response ∠H(e^jω) is an odd function of ω.
What is the relation between Z-transform and DTFT?
Answer
The DTFT is the Z-transform evaluated on the unit circle in the Z-plane. Mathematically, if X(z) is the Z-transform of x(n), then the DTFT X(e^jω) is obtained by substituting z = e^jω, provided the unit circle lies within the region of convergence (ROC) of X(z).
What is zero padding? What are its uses?
Answer
Sign in to view the complete answer paper.
Distinguish between linear convolution and circular convolution of two sequences.
Answer
Sign in to view the complete answer paper.
What is warping effect? What are its effect on magnitude and phase response?
Answer
Sign in to view the complete answer paper.
What are the properties of Chebyshev filter?
Answer
Sign in to view the complete answer paper.
What is the basis for Fourier series methods of design? Why truncation is necessary?
Answer
Sign in to view the complete answer paper.
What is the frequency of designing FIR filter using frequency sampling method?
Answer
Sign in to view the complete answer paper.
What is the need for anti-aliasing filter prior to downsampling?
Answer
Sign in to view the complete answer paper.
What are the methods to prevent overflow?
Answer
Sign in to view the complete answer paper.
PART - B
Determine the stability for the following systems and test the causality: h(n) = u(n); h(n) = 4u(n-2); h(n) = 2u(n); h(n) = e^n u(n); h(n) = 5(3^n)u(n).
Answer
Sign in to view the complete answer paper.
For each impulse response listed below, determine whether the corresponding system is (i) causal (ii) stable. h(n) = sin(πn)δ(n).
Answer
Sign in to view the complete answer paper.
Find the z-transform and ROC of the following sequence: (i) x(n) = (0.25)^n u(n) + (0.5)^n u(n) (ii) (n/3)cos(πn)u(n).
Answer
Sign in to view the complete answer paper.
Determine H(z) for the given systems: y(n) + y(n-1) + 2y(n-2) = x(n). Discuss stability, and if possible determine H(e^jw) from H(z).
Answer
Sign in to view the complete answer paper.
State and prove any two properties of Discrete Fourier series.
Answer
Sign in to view the complete answer paper.
Find 8-point DFT of the sequence x(n) = cos(nπ/4).
Answer
Sign in to view the complete answer paper.
Given x(n) = 2^n and N=8, find X(k) using DIT-FFT algorithm.
Answer
Sign in to view the complete answer paper.
Find the 8-point DFT of the given sequence x(n) = {7,6,5,4,3,2,1,0}.
Answer
Sign in to view the complete answer paper.
Design a digital Butterworth filter satisfying the constraints: 0.75 <= |H(e^jw)| <= 1 for 0 <= w <= π/4 and |H(e^jw)| <= 0.2 for 3π/4 <= w <= π. With T=1 second using impulse invariance.
Answer
Sign in to view the complete answer paper.
Design a Butterworth analog high pass filter that will meet the following specifications: a) Maximum pass band attenuation = 2dB, b) Passband edge frequency = 200rad/sec, c) Minimum stopband attenuation = 20dB, d) Stop band edge frequency = 100 rad/sec.
Answer
Sign in to view the complete answer paper.
Given the desired frequency response H(w) = e^-jw for |w| < 3π/4, and 0 for 3π/4 < |w| < π. Find H(w) for N=7 using a Hanning window.
Answer
Sign in to view the complete answer paper.
What is an FIR filter? Explain the characteristics of FIR filter.
Answer
Sign in to view the complete answer paper.
Determine the frequency response for the symmetric Hanning window w_Han(n) = 0.5(1 + cos(2πn/M)) for -M <= n <= M, otherwise 0. Also find W(ω) when M=1.
Answer
Sign in to view the complete answer paper.
Enumerate the differences between IIR and FIR filters.
Answer
Sign in to view the complete answer paper.
Explain coefficient quantization of IIR filters.
Answer
Sign in to view the complete answer paper.
Explain the polyphase structure of decimator and interpolator.
Answer
Sign in to view the complete answer paper.
Discuss in detail the errors resulting from rounding and truncation.
Answer
Sign in to view the complete answer paper.
Explain the limit cycle oscillations due to product round-off and overflow errors.
Answer
Sign in to view the complete answer paper.