# Impulse Invariance IIR Filter Design MCQ [Free PDF] – Objective Question Answer for Impulse Invariance IIR Filter Design Quiz

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

In the impulse invariance method, our objective is to design an IIR filter having a unit sample response h(n) that is the sampled version of the impulse response of the analog filter. That is
h(n)=h(nT); n=0,1,2…
where T is the sampling interval.

2. If a continuous time signal x(t) with spectrum X(F) is sampled at a rate Fs=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

When a continuous-time signal x(t) with spectrum X(F) is sampled at a rate Fs=1/T samples per second, the spectrum of the sampled signal is periodic repetition.

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

A. X(F)
B. Fs.X(F)
C. X(F)/Fs
D. None of the mentioned

When a continuous-time signal x(t) with spectrum X(F) is sampled at a rate Fs=1/T samples per second, the spectrum of the sampled signal is a periodic repetition of the scaled spectrum Fs.X(F).

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

We know that z=esT
Now substitute s=σ+jΩ and z=r.e, which represents ‘z’ in the polar form
On equating both sides, we get
r=eσT
Thus when σ=0, the value of ‘r’ varies from r=1.

5. What is the equation for normalized frequency?

A. F/Fs
B. F.Fs
C. Fs/F
D. None of the mentioned

In the impulse invariance method, the normalized frequency f is given by
f= F/Fs.

7. Aliasing occurs if the sampling rate Fs is more than twice the highest frequency contained in X(F).

A. True
B. False

Aliasing occurs if the sampling rate Fs is less than twice the highest frequency contained in X(F).

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

A. True
B. False

The above-given frequency response depicts the frequency response of a low-pass analog filter and the frequency response of the corresponding digital filter.

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

A. True
B. False

The digital filter with frequency response H(ω) has the frequency response characteristics of the corresponding analog filter if the sampling interval T is selected sufficiently small to completely avoid or at least minimize the effects of aliasing.

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

A. Low pass
B. Bandpass
C. Low and bandpass
D. High pass