This is the Multiple Choice Questions in Chapter 21: Active Filters from the book **Electronic Principles 7th Edition by Albert Malvino**. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

### Topic Outline

- MCQs in Ideal Responses
- MCQs in Approximate Response
- MCQs in Passive Filters
- MCQs in First-Order stages
- MCQs in VCVS Unity-Gain Second Order Low-Pass Filters
- MCQs in Higher-Order Filters
- MCQs in VCVS Equal-component Low-Pass Filters
- MCQs in VCVS High-Pass Filters
- MCQs in MFB Bandpass Filters
- MCQs in Bandstop Filters
- MCQs in All-Pass Filters
- MCQs in Biquadratic and State-Variable Filters

### Start Practice Exam Test Questions

**Choose the letter of the best answer in each questions.**

1. The region between the passband and the stopband is called the

- a. Attenuation
- b. Center
- c. Transition
- d. Ripple

2. The center frequency of a bandpass filter is always equal to

- a. The bandwidth
- b. Geometric average of the cutoff frequencies
- c. Bandwidth divided by Q
- d. 3-dB frequency

3. The Q of a narrowband filter is always

- a. small
- b. equal to BW divided by f0
- c. less than 1
- d. greater than 1

4. A bandstop filter is sometimes called a

- a. Snubber
- b. Phase shifter
- c. Notch filter
- d. Time-delay circuit

5. The all-pass filter has

- a. No passband
- b. One stopband
- c. the same gain at all frequencies
- d. a fast roll-off above cutoff

6. The approximation with a maximally-flat passband is

- a. Chebyshev
- b. Inverse Chebyshev
- c. Elliptic
- d. Bessel

7. The approximation with a rippled passband is

- a. Butterworth
- b. Inverse Chebyshev
- c. Elliptic
- d. Bessel

8. The approximation that distorts digital signals the least is the

- a. Butterworth
- b. Chebyshev
- c. Elliptic
- d. Bessel

9. If a filter has six second order stages and one first-order stage, the order is

- a. 2
- b. 6
- c. 7
- d. 13

10. If a Butterworth filter has 9 second-order stages, its roll-off rate is

- a. 20 dB per decade
- b. 40 dB per decade
- c. 180 dB per decade
- d. 360 dB per decade

11. If n = 10, the approximation with the fastest roll-off in the transition region is

- a. Butterworth
- b. Chebyshev
- c. Inverse Chebyshev
- d. Elliptic

12. The elliptic approximation has a

- a. Slow roll-off rate compared to the Cauer
- b. Rippled stopband
- c. Maximally-flat passband
- d. Monotonic stopband

13. Linear phase shift is equivalent to

- a. Q = 0.707
- b. Maximally-flat stopband
- c. Constant time delay
- d. Rippled passband

14. The filter with the slowest roll-off rate is the

- a. Butterworth
- b. Chebyshev
- c. Elliptic
- d. Bessel

15. A first-order active-filter stage has

- a. One capacitor
- b. Two op amps
- c. Three resistors
- d. a high Q

16. A first-order stage cannot have a

- a. Butterworth response
- b. Chebyshev response
- c. Maximally-flat passband
- d. Rolloff rate of 20 dB per decade

17. Sallen-Key filters are also called

- a. VCVS filters
- b. MFB filters
- c. Biquadratic filters
- d. State-variable filters

18. To build a 10th-order filter, we should cascade

- a. 10 first-stage stages
- b. 5 second-order stages
- c. 3 third-order stages
- d. 2 fourth-order stages

19. To get a Butterworth response with an 8th-order filter, the stages need to have

- a. Equal Q’s
- b. Unequal center frequencies
- c. Inductors
- d. Staggered Q’s

20. To get a Chebyshev response with a 12th-order filter, the stages need to have

- a. Equal Q’s
- b. Equal center frequencies
- c. Staggered bandwidths
- d. Staggered center frequencies and Q’s

21. The Q of a Sallen-Key second-order stage depends on the

- a. Voltage gain
- b. Center frequency
- c. Bandwidth
- d. GBW of the op amp

22. With Sallen-Key high-pass filters, the pole frequency must be

- a. Added to the K values
- b. Subtracted from the K values
- c. Multiplied by the K values
- d. Divided by the K values

23. If BW increases, the

- a. Center frequency decreases
- b. Q decreases
- c. Roll-off rate increases
- d. Ripples appear in the stopband

24. When Q is greater than 1, a bandpass filter should be built with

- a. Low-pass and high-pass stages
- b. MFB stages
- c. Notch stages
- d. All-pass stages

25. The all-pass filter is used when

- a. High roll-off rates are needed
- b. Phase shift is important
- c. A maximally-flat passband is needed
- d. A rippled stopband is important

26. A second-order all-pass filter can vary the output phase from

- a. 90 degrees to -90 degrees
- b. 0 degrees to -180 degrees
- c. 0 degrees to -360 degrees
- d. 0 degrees to -720 degrees

27. The all-pass filter is sometimes called a

- a. Tow-Thomas filter
- b. Delay equalizer
- c. KHN filter
- d. State-variable filter

28. The biquadratic filter

- a. Has low component sensitivity
- b. Uses three or more op amps
- c. Is also called Tow-Thomas filter
- d. All of the above

29. The state-variable filter

- a. Has a low-pass, high-pass, and bandpass output
- b. Is difficult to tune
- c. Has high component sensitivity
- d. Uses less than three op amps

30. If GBW is limited, the Q of the stage will

- a. Remain the same
- b. Double
- c. Decrease
- d. Increase

31. To correct for limited GBW, a designer may use

- a. A constant time delay
- b. Predistortion
- c. Linear phase shift
- d. A rippled passband