Digital Signal Processing Multiple Choice Questions and Answers

1 If an LTI system is described by the difference equation y(n)=ay(n-1)+bx(n), 0 < a < 1, then what is the parameter ‘b’ so that the maximum value of |H(ω)| is unity?

A a

B 1-a

C 1+a

D none of the mentioned

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Answer:1-a

2 The output of the Linear time invariant system cannot contain the frequency components that are not contained in the input signal.

A True

B False

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Answer:True

3 An ideal filter should have unity gain in their stop band.

A True

B False

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Answer:False

4 Which filter has a magnitude frequency response as shown in the plot given below?

Digital Signal Processing

A Low pass Filter

B High pass Filter

C Band pass Filter

D Band stop Filter

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Answer:Band stop Filter

5 An ideal filter should have zero gain in their stop band.

A True

B False

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Answer:True

6 The ‘Envelope delay’ or ‘Group delay’ is the time delay that the signal component of frequency ω undergoes as it passes from the input to the output of the system.

A True

B False

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Answer:True

7 If the phase ϴ(ω) of the system is linear, then the group delay of the system?

A Increases with frequency of signal

B Constant

C Decreases with frequency of signal

D Independent of frequency of signal

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Answer:Constant

8 If h_lp(n) denotes the impulse response of a low pass filter with frequency response H_lp(ω), then what is the frequency response of the high pass filter in terms of H_lp(ω)?

A H_lp(ω-π/2)

B H_lp(ω+π/2)

C H_lp(ω-π)

D H_lp(ω+π)

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Answer:H_lp(ω-π)

9 If the low pass filter described by the difference equation y(n)=0.9y(n-1)+0.1x(n) is converted into a high pass filter, then what is the frequency response of the high pass filter?

A 0.1/(1+0.9e^jω)

B 0.1/(1+0.9e^-jω)

C 0.1/(1-0.9e^jω)

D None of the mentioned

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