# Frequency Transformations MCQ’s

This set of Digital Signal Processing Multiple Choice Questions & Answers (MCQs) focuses on “Frequency Transformations”.

1. Which of the following is the backward design equation for a low pass-to-low pass transformation?

a) \(\Omega_S=\frac{\Omega_S}{\Omega_u}\)

b) \(\Omega_S=\frac{\Omega_u}{\Omega’_S}\)

c) \(\Omega’_S=\frac{\Omega_S}{\Omega_u}\)

d) \(\Omega_S=\frac{\Omega’_S}{\Omega_u}\)

2. If A=\(\frac{Ω_1 (Ω_u-Ω_l)}{-Ω_1^2+Ω_u Ω_l}\) and B=\(\frac{Ω_2 (Ω_u-Ω_l)}{Ω_2^2-Ω_u Ω_l}\), then which of the following is the backward design equation for a low pass-to-band stop transformation?

a) Ω_{S}=Max{|A|,|B|}

b) Ω_{S}=Min{|A|,|B|}

c) Ω_{S}=|B|

d) Ω_{S}=|A|

3. If H(s) is the transfer function of a analog low pass normalized filter and Ω_{u} is the desired pass band edge frequency of new low pass filter, then which of the following transformation has to be performed?

a) s → s/Ω_{u}

b) s → s.Ω_{u}

c) s → Ω_{u}/s

d) none of the mentioned

4. What is the pass band edge frequency of an analog low pass normalized filter?

a) 0 rad/sec

b) 0.5 rad/sec

c) 1 rad/sec

d) 1.5 rad/sec

5. If A=\(\frac{-Ω_1^2+Ω_u Ω_l}{Ω_1 (Ω_u-Ω_l)}\) and B=\(\frac{Ω_2^2-Ω_u Ω_l}{Ω_2 (Ω_u-Ω_l)}\), then which of the following is the backward design equation for a low pass-to-band pass transformation?

a) Ω_{S}=|B|

b) Ω_{S}=|A|

c) Ω_{S}=Max{|A|,|B|}

d) Ω_{S}=Min{|A|,|B|}

6. Which of the following is a low pass-to-band pass transformation?

a) s→\(\frac{s^2+Ω_u Ω_l}{s(Ω_u+Ω_l)}\)

b) s→\(\frac{s^2-Ω_u Ω_l}{s(Ω_u-Ω_l)}\)

c) s→\(\frac{s^2+Ω_u Ω_l}{s(Ω_u-Ω_l)}\)

d) s→\(\frac{s^2-Ω_u Ω_l}{s(Ω_u+Ω_l)}\)

7. Which of the following is the backward design equation for a low pass-to-high pass transformation?

a) \(\Omega_S=\frac{\Omega_S}{\Omega_u}\)

b) \(\Omega_S=\frac{\Omega_u}{\Omega’_S}\)

c) \(\Omega’_S=\frac{\Omega_S}{\Omega_u}\)

d) \(\Omega_S=\frac{\Omega’_S}{\Omega_u}\)

8. Which of the following is a low pass-to-high pass transformation?

a) s → s / Ω_{u}

b) s → Ω_{u}/s

c) s → Ω_{u}.s

d) none of the mentioned

9. Which of the following is a low pass-to-high pass transformation?

a) s → s / Ω_{u}

b) s → Ω_{u} / s

c) s → Ω_{u}.s

d) none of the mentioned

10. Which of the following is a low pass-to-band stop transformation?

a) s→\(\frac{s(Ω_u-Ω_l)}{s^2+Ω_u Ω_l}\)

b) s→\(\frac{s(Ω_u+Ω_l)}{s^2+Ω_u Ω_l}\)

c) s→\(\frac{s(Ω_u-Ω_l)}{s^2-Ω_u Ω_l}\)

d) none of the mentioned

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