Digital Signal Processing Multiple Choice Questions on “Design of IIR Filters in Frequency Domain”.
1. Filter parameter optimization technique is used for designing of which of the following?
A. FIR in time domain
B. FIR in frequency domain
C. IIR in time domain
D. IIR in frequency domain
Answer: D
Clarification: We describe a filter parameter optimization technique carried out in the frequency domain that is representative of frequency domain design methods.
2. In this type of designing, the system function of IIR filter is expressed in which form?
A. Parallel form
B. Cascade form
C. Mixed form
D. Any of the mentioned
Answer: B
Clarification: The design is most easily carried out with the system function for the IIR filter expressed in the cascade form as
H(z)=G.A(z).
3. It is more convenient to deal with the envelope delay as a function of frequency.
A. True
B. False
Answer: A
Clarification: Instead of dealing with the phase response ϴ(ω), it is more convenient to deal with the envelope delay as a function of frequency.
4. Which of the following gives the equation for envelope delay?
A. dϴ(ω)/dω
B. ϴ(ω)
C. -dϴ(ω)/dω
D. -ϴ(ω)
Answer: C
Clarification: Instead of dealing with the phase response ϴ(ω), it is more convenient to deal with the envelope delay as a function of frequency, which is
Tg(ω)= -dϴ(ω)/dω.
5. What is the error in magnitude at the frequency ωk?
A. G.A(ωk) + Ad(ωk)
B. G.A(ωk) – Ad(ωk)
C. G.A(ωk) – A(ωk)
D. None of the mentioned
Answer: B
Clarification: The error in magnitude at the frequency ωk is G.A(ωk) – Ad(ωk) for 0 ≤ |ω| ≤ π, where Ad(ωk) is the desired magnitude response at ωk.
6. What is the error in delay at the frequency ωk?
A. Tg(ωk)-Td(ωk)
B. Tg(ωk)+Td(ωk)
C. Td(ωk)
D. None of the mentioned
Answer: A
Clarification: Similarly as in the previous question, the error in delay at ωk is defined as Tg(ωk)-Td(ωk), where Td(ωk) is the desired delay response.
7. The choice of Td(ωk) for error in delay is complicated.
A. True
B. False
Answer: A
Clarification: We know that the error in delay is defined as Tg(ωk) – Td(ωk). However, the choice of Td(ωk) for error in delay is complicated by the difficulty in assigning a nominal delay of the filter.
8. If the error in delay is defined as Tg(ωk) – Tg(ω0) – Td(ωkk), then what is Tg(ω0)?
A. Filter delay at nominal frequency in stop band
B. Filter delay at nominal frequency in transition band
C. Filter delay at nominal frequency
D. Filter delay at nominal frequency in pass band
Answer: D
Clarification: We are led to define the error in delay as Tg(ωk) – Tg(ω0) – Td(ωk), where Tg(ω0) is the filter delay at some nominal centre frequency in the pass band of the filter.
9. We cannot choose any arbitrary function for the errors in magnitude and delay.
A. True
B. False