FIR Filters multiple choice questions

 FIR Filters

1. What is the value of h(M-1/2) if the unit sample response is anti-symmetric?
a) 0
b) 1
c) -1
d) None of the mentioned
Answer: 0
2. Which of the following condition should the unit sample response of a FIR filter satisfy to have a linear phase?
a) h(M-1-n) n=0,1,2…M-1
b) ±h(M-1-n) n=0,1,2…M-1
c) -h(M-1-n) n=0,1,2…M-1
d) None of the mentioned
Answer: ±h(M-1-n) n=0,1,2…M-1
3. If the unit sample response h(n) of the filter is real, complex valued roots need not occur in complex conjugate pairs.
a) True
b) False
Answer: False
4. The lower and upper limits on the convolution sum reflect the causality and finite duration characteristics of the filter.
a) True
b) False
Answer: True
5. The anti-symmetric condition is not used in the design of low pass linear phase FIR filter.
a) True
b) False
Answer: True
6. The roots of the polynomial H(z) are identical to the roots of the polynomial   H(z^-1).
a) True
b) False
Answer: True
7. The roots of the equation H(z) must occur in __________
a) Identical
b) Zero
c) Reciprocal pairs
d) Conjugate pairs
Answer: Reciprocal pairs
8. What is the number of filter coefficients that specify the frequency response for h(n) symmetric?
a) (M-1)/2 when M is odd and M/2 when M is even
b) (M-1)/2 when M is even and M/2 when M is odd
c) (M+1)/2 when M is even and M/2 when M is odd
d) (M+1)/2 when M is odd and M/2 when M is even
Answer: (M+1)/2 when M is odd and M/2 when M is even
9. Which of the following is not suitable either as low pass or a high pass filter?
a) h(n) symmetric and M odd
b) h(n) symmetric and M even
c) h(n) anti-symmetric and M odd
d) h(n) anti-symmetric and M even
Answer: h(n) anti-symmetric and M odd
10. What is the number of filter coefficients that specify the frequency response for h(n) anti-symmetric?
a) (M-1)/2 when M is even and M/2 when M is odd
b) (M-1)/2 when M is odd and M/2 when M is even
c) (M+1)/2 when M is even and M/2 when M is odd
d) (M+1)/2 when M is odd and M/2 when M is even
Answer: (M-1)/2 when M is odd and M/2 when M is even
11. The anti-symmetric condition with M even is not used in the design of which of the following linear-phase FIR filter?
a) Low pass
b) High pass
c) Band pass
d) Bans stop
Answer: Low pass
12. Which of the following is the difference equation of the FIR filter of length M, input x(n) and output y(n)?
a) y(n)=∑^M+1k=0 bkx(n+k)
b) y(n)=∑^M+1k=0 bkx(n−k)
c) y(n)=∑^M−1k=0 bkx(n−k)
d) None of the mentioned
Answer: y(n)=∑^M−1k=0 bkx(n−k)
13. If H(z) is the z-transform of the impulse response of an FIR filter, then which of the following relation is true?
a) z^M+1.H(z^-1)=±H(z)
b) z^-(M+1).H(z^-1)=±H(z)
c) z^(M-1).H(z^-1)=±H(z)
d) z^-(M-1).H(z^-1)=±H(z)
Answer: z^-(M-1).H(z^-1)=±H(z)
14. Consider the assertions given below. Which among them is an advantage of FIR Filter?
a) Necessity of computational techniques for filter implementation
b) Requirement of large storage
c) Incapability of simulating prototype analog filters
d) Presence of linear phase response
Answer: Presence of linear phase response
15. In Gibb's phenomenon, the ringing effect is predominantly present near the ______ .
a) bandgap
b) bandedge
c) bandwidth
d) bandshell
Answer: bandedge
16. Which window function is also regarded as 'Raised-cosine window'?
a) Hamming window
b) Hanning window
c) Barlett window
d) Blackman window
Answer: Hanning window
17. Which among the following represent/s the characteristic/s of an ideal filter?
a) Constant gain in passband
b) Zero gain in stop band
c) Linear Phase Response
d) All of the above 
Answer: All of the above
18. For a linear phase filter, if Z₁ is zero then what would be the value of Z₁^-1 or 1/ Z₁?
a) Zero
b) Unity
c) Infinity
d) Unpredictable
Answer: Zero
19. FIR filters ________
A. are non-recursive
B. do not adopt any feedback
C. are recursive
D. use feedback
a) A & B
b) C & D
c) A & D
d) B & C
Answer: A & B
20. A filter is said to be linear phase filter if the phase delay and group delay are _______
a) High
b) Moderate
c) Low
d) Constant
Answer: Constant
21. In Barlett window, the triangular function resembles the tapering of rectangular window sequence _______ from the middle to the ends.
a) linearly
b) elliptically
c) hyperbolically
d) parabolically
Answer: linearly
22. Basically, group delay is the delayed response of filter as a function of ________.
a) Phase
b) Amplitude
c) Frequency
d) All of the above
Answer: Frequency
23. In FIR filter design, which among the following parameters is/are separately controlled by using Kaiser window?
a) Order of filter (M)
b) Transition width of main lobe
c) Both a and b
d) None of the above
Answer: Both a and b
24. Linear phase response of the filter is defined as
a) When the phase response of the system varies linearly with the frequency function.
b) When the phase response of the system varies inversely with the frequency function.
c) When the phase response of the system does not vary linearly with the frequency function.
d) None of the above.
Answer: When the phase response of the system varies linearly with the frequency function.
25. Which of the following statement is/are incorrect about the FIR filters?
i. FIR filters are always stable.
ii. It requires more memory as compared to IIR filters.
iii. FIR filters are non-canonical.
iv. Its linear phase realization structure can be easily designed.
a) i and ii
b) Only ii
c) Only iii
d) iii and iv
Answer: Only iii