Malvino Chapter 21
1. The region between the passband and the stopband is called the
a. Attenuation
b. Center
c. Transition
d. Ripple
c
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
b
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
d
4. A bandstop filter is sometimes called a
a. Snubber
b. Phase shifter
c. Notch filter
d. Time-delay circuit
c
5. The all-pass filter has
a. No passband
b. One stopband
c. the same gain at all frequencies
d. a fast rolloff above cutoff
c
6. The approximation with a maximally-flat passband is
a. Chebyshev
b. Inverse Chebyshev
c. Elliptic
d. Bessel
b
7. The approximation with a rippled passband is
a. Butterworth
b. Inverse Chebyshev
c. Elliptic
d. Bessel
c
8. The approximation that distorts digital signals the least is the
a. Butterworth
b. Chebyshev
c. Elliptic
d. Bessel
d
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
d
10. If a Butterworth filter has 9 second-order stages, its rolloff rate is
a. 20 dB per decade
b. 40 dB per decade
c. 180 dB per decade
d. 360 dB per decade
d
11. If n = 10, the approximation with the fastest rolloff in the transition region is
a. Butterworth
b. Chebyshev
c. Inverse Chebyshev
d. Elliptic
d
12. The elliptic approximation has a
a. Slow rolloff rate compared to the Cauer
b. Rippled stopband
c. Maximally-flat passband
d. Monotonic stopband
b
13. Linear phase shift is equivalent to
a. Q = 0.707
b. Maximally-flat stopband
c. Constant time delay
d. Rippled passband
c
14. The filter with the slowest rolloff rate is the
a. Butterworth
b. Chebyshev
c. Elliptic
d. Bessel
d
15. A first-order active-filter stage has
a. One capacitor
b. Two op amps
c. Three resistors
d. a high Q
a
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
b
17. Sallen-Key filters are also called
a. VCVS filters
b. MFB filters
c. Biquadratic filters
d. State-variable filters
a
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
b
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
d
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
d
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
a
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
d
23. If BW increases, the
a. Center frequency decreases
b. Q decreases
c. Rolloff rate increases
d. Ripples appear in the stopband
b
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
b
25. The all-pass filter is used when
a. High rolloff rates are needed
b. Phase shift is important
c. A maximally-flat passband is needed
d. A rippled stopband is important
b
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
c
27. The all-pass filter is sometimes called a
a. Tow-Thomas filter
b. Delay equalizer
c. KHN filter
d. State-variable filter
b
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
d
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
a
30. If GBW is limited, the Q of the stage will
a. Remain the same
b. Double
c. Decrease
d. Increase
d
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
b
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