# MCQs in Active Filters

Multiple Choice Questions in Active Filters from the book Electronic Principles by Albert Malvino. Make sure to familiarize each and every questions

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

### Begin and Good luck!

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
• 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

• 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

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