Digital Filters (FIR, IIR) — MCQs – EE

1. A digital filter is used to:
(A) Process analog signals
(B) Modify discrete-time signals
(C) Store digital data
(D) Amplify analog voltage

2. The two main types of digital filters are:
(A) Low-pass and high-pass
(B) FIR and IIR
(C) Analog and digital
(D) Time and frequency

3. FIR stands for:
(A) Finite Impulse Response
(B) Final Input Response
(C) Frequency Impulse Ratio
(D) Fixed Input Rate

4. IIR stands for:
(A) Infinite Impulse Response
(B) Integrated Input Response
(C) Initial Impulse Rate
(D) Inverse Input Relation

5. In FIR filters, the impulse response:
(A) Is infinite in duration
(B) Is finite in duration
(C) Is nonlinear
(D) Is undefined

6. In IIR filters, the impulse response:
(A) Is finite
(B) Is infinite
(C) Is always zero
(D) Is constant

7. FIR filters are always:
(A) Stable
(B) Unstable
(C) Nonlinear
(D) Approximate

8. IIR filters can be:
(A) Only stable
(B) Only unstable
(C) Stable or unstable
(D) Always linear

9. FIR filters do not use:
(A) Feedback
(B) Feedforward
(C) Coefficients
(D) Sampling

10. IIR filters use:
(A) Only feedforward
(B) Only feedback
(C) Both feedback and feedforward
(D) Neither

11. FIR filters are commonly designed using:
(A) Windowing methods
(B) RLC circuits
(C) Laplace transforms
(D) Phase modulation

12. IIR filters are often designed using:
(A) Analog filter transformations
(B) Fourier synthesis
(C) Digital modulation
(D) Wavelet functions

13. FIR filters are preferred when:
(A) Linear phase response is required
(B) Nonlinear phase is acceptable
(C) Speed is critical
(D) Memory is limited

14. IIR filters are preferred when:
(A) Low computational cost is needed
(B) Linear phase is critical
(C) Phase distortion must be zero
(D) Filter order must be high

15. The order of a filter determines:
(A) The filter’s delay
(B) The steepness of transition
(C) The sampling rate
(D) The phase only

16. FIR filters require:
(A) More coefficients than IIR filters for the same response
(B) Fewer coefficients than IIR filters
(C) No coefficients
(D) Only one coefficient

17. IIR filters are generally:
(A) More memory-efficient
(B) Less stable
(C) Linear-phase
(D) Time-invariant

18. A disadvantage of IIR filters is:
(A) Nonlinear phase response
(B) High computational cost
(C) Infinite delay
(D) No feedback path

19. FIR filters are often implemented using:
(A) Convolution operations
(B) Integration
(C) Differentiation
(D) Matrix inversion

20. IIR filters are recursive because:
(A) They use feedback from previous outputs
(B) They depend only on input samples
(C) They use linear addition
(D) They ignore past outputs

21. FIR filters are non-recursive because:
(A) They depend only on input samples
(B) They use feedback
(C) They depend on past outputs
(D) They are nonlinear

22. The stability of IIR filters depends on:
(A) Pole locations
(B) Zero locations only
(C) Input magnitude
(D) Sampling rate

23. A filter with poles outside the unit circle is:
(A) Stable
(B) Unstable
(C) Linear
(D) Ideal

24. FIR filters have zeros but no:
(A) Poles
(B) Coefficients
(C) Inputs
(D) Gains

25. IIR filters generally exhibit:
(A) Nonlinear phase
(B) Linear phase
(C) Constant delay
(D) Phase compensation

26. A key advantage of FIR filters is:
(A) Exact linear phase can be achieved
(B) Infinite memory requirement
(C) Low computation speed
(D) Variable sampling rate

27. The frequency response of digital filters is periodic due to:
(A) Discrete-time nature
(B) Sampling noise
(C) Aliasing
(D) Quantization

28. The impulse response of an IIR filter decays:
(A) Exponentially
(B) Linearly
(C) Instantly
(D) Randomly

29. The main disadvantage of FIR filters is:
(A) Higher order required for sharp response
(B) Nonlinear phase
(C) Instability
(D) Complex design process

30. Digital filters are commonly used in:
(A) Audio and image processing
(B) Power generation
(C) Motor control only
(D) Battery charging