This set of Digital Signal Processing Questions for campus interviews focuses on “IIR Filter Design by Impulse Invariance”.

1. By impulse invariance method, the IIR filter will have a unit sample response h(n) that is the sampled version of the analog filter.**a) True**

b) False

2. If a continuous time signal x(t) with spectrum X(F) is sampled at a rate F_{s}=1/T samples per second, the spectrum of the sampled signal is _____________

a) Non periodic repetition

b) Non periodic non-repetition**c) Periodic repetition**

d) None of the mentioned

3. If a continuous time signal x(t) with spectrum X(F) is sampled at a rate F_{s}=1/T samples per second, then what is the scaled spectrum?

a) X(F)**b) F _{s}.X(F)**

c) X(F)/F

_{s}

d) None of the mentioned

4. When σ=0, then what is the condition on ‘r’?

a) 0<r<1**b) r=1**

c) r>1

d) None of the mentioned

5. What is the equation for normalized frequency?**a) F/F _{s}**

b) F.F

_{s}

c) F

_{s}/F

d) None of the mentioned

6. Aliasing occurs if the sampling rate F_{s} is more than twice the highest frequency contained in X(F).

a) True**b) False**

7. Which of the filters have a frequency response as shown in the figure below?

a) Analog filter

b) Digital filter without aliasing**c) Digital filter with aliasing**

d) None of the mentioned

8. The frequency response given in the above question is for a low pass digital filter.**a) True**

b) False

9. Sampling interval T is selected sufficiently large to completely avoid or at least minimize the effects of aliasing.

a) True**b) False**

10. Which of the following filters cannot be designed using impulse invariance method?

a) Low pass

b) Band pass

c) Low and band pass**d) High pass**

11. Which of the following is the correct relation between ω and Ω?

a) Ω=ωT

b) T=Ωω**c) ω=ΩT**

d) None of the mentioned

12. When σ<0, then what is the condition on ‘r’?**a) 0<r<1**

b) r=1

c) r>1

d) None of the mentioned

13. When σ>0, then what is the condition on ‘r’?

a) 0<r<1

b) r=1**c) r>1**

d) None of the mentioned

14. What is the period of the scaled spectrum F_{s}.X(F)?

a) 2F_{s}

b) F_{s}/2

c) 4F_{s}**d) F _{s}**