# Networks pq set 3

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1. The MATLAB program fft935.m uses the command Pxx = X.*conj(X)/(N/2) which computes
• power spectral density at each frequency
• both of these
• energy in the x(t) at each frequency
2. The MATLAB program fft935.m uses the command X = fft(x,N) where ___ is the variable containing a bunch of complex numbers.
X
3. The MATLAB program fft935.m uses the command X = fft(x,N) where ___ is the function that performs the Fourier Transform.
fft
4. The MATLAB program fft935.m uses the command X = fft(x,N) where ___ is the number of values of x and X.
N
5. . The MATLAB program fft935.m uses the command X = fft(x,N) where ___ is the time-domain signal
x
6. Ex935 requires the MATLAB program fft935.m which performs an FFT. The number of lines of program code required for the FFT function is
1
7. Ex935 requires the MATLAB program fft935.m which computes and plots the Fourier Transform of x(t).
true
8. Ex935 requires the MATLAB program fft935.m implements the Fourier Transform using a specific implemention:
fft - Fast Fourier Transform
9. Ex935 requires the MATLAB program fft935.m which is also called a
script
10. Ex935 generates a time-domain signal where the signal-to-noise ratio is nearly
0.3
11. Ex935 generates a time-domain signal with 3 sinusoids and noise with a peak-to-peak amplitude of nearly
60
12. Ex935 generates a time-domain signal with 3 sinusoids with a peak-to-peak amplitude of nearly
16
13. Ex935 generates a time-domain signal with 3 sinusoids that have ____ frequencies and _____ amplitudes.
different, different
14. Ex935 generates a time-domain signal containing _____ values.
4096
15. Ex935 generates a time-domain signal containing _____.
noise or random numbers, which are the same thing
16. Ex935 generates a time-domain signal containing ____ sine components.
3
the Fourier Transform
18. For a Bode phase of 85 degrees, and an input of A*sin(w*t), the output at that frequency would be
B*sin(w*t+85 deg)
19. For a Bode gain of -20 dB, and an input of 30sin(w*t), the output at that frequency would be
3sin(w*t+theta)
20. For a Bode gain of -20 dB, the system numeric gain at that frequency is
0.1
21. A Bode plot shows output and input sine wave ratios over a wide range of frequencies.
true
22. A Bode plot shows the sinusoidal output signal for a linear system relative to the sinusoidal input signal.
true
23. A high-pass Bode phase plot shows nearly _____ phase at low frequency and nearly ______ phase at high frequency.
90, 0
24. A high-pass Bode gain plot shows _____ gain at low frequency and ______ gain at high frequency.
low, high
25. The Bode phase plot is
phase in degrees vs frequency in rad/sec
26. The Bode gain plot is
gain in dB vs frequency in rad/sec
27. Both Bode plot gain and phase plots are ______ plots.
semilog
28. Both Bode plot gain and phase axes are
linear scales
29. In both Bode plot gain and phase axes, _____ axes are different in both plots.
vertical
30. The Bode plot frequency axis is a
log scale
31. The Bode plot frequency axis is the
horizontal axis and is the same for both plots
32. The bottom Bode plot is
system phase vs frequency
33. The top Bode plot is
system gain vs frequency
34. A Bode plot is
two plots
35. A Bode plot is a description of a
linear system
36. Vout/Vin = -R2/R1 is a number (e.g. -3), therefore Vout =
-3*Vin
37. Vout/Vin = -R2/R1 is a number and is also called the ____ of the inverting opamp configuration
gain
38. An ameteur mastake occurs in the audio portion of the video since KVL is mentioned, but KCL should have been stated.
t/f
true
39. The power-supply ground for the internal opamp circuit (not the noninverting input) is
not connected to the opamp
40. The non-inverting input (positive input port) is grounded in the inverting opamp configuration because
0 volts is desired at the inverting input.
41. The positive and negative supply voltages in the opamp video
are present but not shown
42. Negative in the inverting opamp transfer function (-R2/R1) means
• both of these
• negative input produces positive output voltage
• positive input produces negative output voltage
43. The transfer function (Vout/Vin) of an inverting opamp configuration like in the video is
-Z2(s)/Z1(s)
44. The transfer function (Vout/Vin) of the inverting opamp configuration in the video is
-R2/R1
45. What does an opamp with negative feedback do? It makes the voltage at the negative input port the same as the voltage at the positive input port.
true if opamp limits of voltage and current are not exceeded
46. The ideal-opamp current (ma) to the signal-input ports is about
0
47. How many signal output ports does the opamp have?
1
48. The opamp has ____ power ports (voltage-supply inputs).
2
49. The opamp has ____ signal-input ports.
2
50. An opamp with a resitor in negative feedback and another resistor that is connected from the input signal to the negative input port is _____. The positive input port is grounded.
an inverting amplifier
51. The opamp with its many external configurations is one of the most useful electronic circuits.
t/f
true
52. A transfer function is a _______-domain concept.
complex-vaiable s
53. A transfer function is a ratio of two
s-domain signals (output divided by input)
54. A transfer function is a linear-system ____-domain I/O relationship for which input and output signals ______.
s, may be unknown
55. Voltage and current are common examples of ______ in ______ engineering.
signals, electrical
56. Position, velocity, acceleration, pressure, temperature, humidity are common examples of ____ in ____ engineering
signals, mechanical
57. Common electrical and mechanical signals
can be expressed in the time domain and the s-domain
58. The linear-system transfer function can be determined without knowing input or output signals.
t/f
true
59. The linear-system transfer function (TF) can be written without knowing input or output signals, and the TF = output/input.
t/f
true
60. TF1 and TF2 are in series. TF= combination of both. TF=
TF1*TF2
61. TF1 and TF2 are in parellel. TF= combination of both. TF=
TF1+TF2
62. TF1 is the forward TF. TF2 is the feedback TF in a _____ feedback path. The combination of both is TF=
negative, TF1/(1+TF1*TF2)
63. The TF=(s+a)/(s+b) has
one real pole at s=-b
64. The TF=25/(s^2+6s+25) = 25/( (s+3)^2 + 4^2 ) has
a pair of complex poles at s=-3+j4 and s=-3-j4
65. The TF=25/(s^2+6s+25) = 25/( (s+3)^2 + 4^2 ) is an example of
a 2nd-order TF
66. The TF=25/(s^2+6s+25) can also be written as TF=wn^2/(s^2 + 2*zeta*wn*s + wn^2)
t/f
true
67. In the TF=wn^2/(s^2 + 2*zeta*wn*s + wn^2), wn is
68. In the TF=wn^2/(s^2 + 2*zeta*wn*s + wn^2), zeta is
damping ratio with no units
69. In the TF=25/(s^2+6s+25), the undamped natural frequency is _____ rad/sec.
5
70. In the TF=25/(s^2+6s+25), the damping ratio is
0.6
71. Damping ratio (zeta) and undamped natural frequency (wn) are ____-domain concepts.
s
72. Specific values of damping ratio (zeta) and undamped natural frequency (wn) ___ related to time-domain concepts.
are
73. 4/0 is
infinity
74. -1.1E-15/0 is
negative infinity
75. The calculator reading (1.2E-14 to 1.2E-15) should be interpreted as
a value of zero due to roundoff at calculator limits
76. An electrical system with an infinite impedance
draws zero current and may have non-zero voltage across it, and KVL still applies to the loop.
77. Can a bunch of sine and cosine functions be added to approximate any function that is periodic or not periodic?
yes
78. Can a bunch of sine and cosine functions be added to make any periodic function?
yes
79. Can a bunch of sine and cosine functions be added to make a square-wave function?
yes
80. Can a bunch of sine and cosine functions be added to make a triangle function?
yes
81. The second-Fourier-Series component has a frequence that is ____ the fundamental frequency.
exactly two times
82. The first Fourier Series component is called the fundamental or first harmonic.
true
83. The Fourier Series components are also called harmonics.
true
84. The Fourier Series componenents are all
sinusoids
85. If the time-domain signal x(t) is not periodic, the X(f) will be the Fourier Transform.
true
86. If the time-domain signal x(t) is periodic, the X(f) will be the Fourier Series.
true
87. X(f) is the _____ of the time-domain signal x(t).
Fourier Transform or Fourier Series
88. The diagram that shows (human voice - electronic signal - EM wave - electronic signal - human voice) introduces
signal processing
89. Which domain is used when making a Bode plot?
jw domain
90. Bode Plots deal with ______ input and output signals.
sinusoidal
91. Time invariant in a LTI system means a time delay of the input signal results in ______ time delay of the output signal.
the same
92. Which of the following is true about a LTI system?
• both of these
• The signals scale
• Two times the input signal results in two times the output signal.
93. LTI stands for
Linear and Time Invariant
94. The delay TF has Bode-gain that _____ as frequency increases.
remains constant
95. The delay has Bode-phase that _____ as frequency increases.
decreases
96. The second-order lag has Bode-gain slope of ____ after the corner
97. The integrator has Bode-gain slope of ____ over all frequencies.
98. The differentiator has Bode-gain slope of ____ over all frequencies.
99. The first-order lag has a Bode-gain slope of _____ after the corner.
100. The first-order lead has a Bode-gain slope of _____ after the corner.
101. G(s) = exp(-a*s)
delay
102. G(s) = s
differentiator
103. G(s) = 1/s
integrator
104. G(s) = a/(s^2 + b*s + w1^2)
second-order lag
105. (s) = a / ( (s+w1) * (s+w2) )
double lag
106. G(s) = a/(s+w1)
first-order lag
107. G(s) = a*(s+w1)
108. G(s)=(s+a)/(s+b), and in Bode-plot form, G(s)=
(a/b)(1+s/a)/(1+s/b)
109. G(s)=1/(s^2+a*s+b), and in Bode-plot form, G(s)=
(1/b)/(1+a*s/b+s^2/b)
110. G(s)=1/((s+b)(s+a)), and in Bode-plot form, G(s)=
(1/(a*b))/((1+s/b)(1+s/a))
111. G(s)=1/(s(s+a)), and in Bode-plot form, G(s)=
(1/a)/(s(1+s/a))
112. G(s)=1/((s+b)(s+a)), and in Bode-plot form, G(s)=
(1/(a*b))/((1+s/b)(1+s/a))
113. The system TF must be written in _____ in order to manually sketch asymptotic Bode plots
factored-polynomial form
114. The system TF must be written in _____ in order to manually sketch asymptotic Bode plots
system transfer functions
115. Deviations of asymptotic Bode plots from actual Bode plots occur at the
corners
116. Asympotic Bode plots are
straight-line approximations
117. A delta function has _____ height and _____ width and _____ area.
infinite, zero, unit
118. The width of the rectangular pulse (hat function) is
tau
119. The height of the rectangular pulse (hat function) is
A
120. The integral from -infinity to +infinity of delta(t) is
1
121. Equations 6,7 and 8 were derived from equation 4, which is _____ the capability of the student of beginning calculus.
well within
122. Equations 6,7 and 8 were derived from equation
4
123. Equations 6,7 and 8 have something in common:
no imaginary part
124. Equation 7 is easily visualized as most like
1/f^2
125. Equation 8 is the Fourier transform of a
delta function
126. Equation 7 is the Fourier transform of a
two-sided exponential
127. Equation 6 is a
sinc function
128. Equation 6 is the Fourier transform of a
pulse or hat function
129. X_bar_n in equation 3 is ____ and X_bar(f) in equation 4 is a ____.
discrete set, continuous function
130. X_bar_n in equation 3 and X_bar(f) in equation 4 are both complex
true
131. The period of the periodic signal in equations 1-3 is
T
132. An, Bn, and Xn are _____ in number theoretically, and _____ in practice.
infinite, small
133. Equation 4 is theoretically interesting, but is not practical because of the infinite limits.
false
134. Equation 4 is theoretically interesting, but is not practical because of the infinite limits.
x(t)
135. Which equation shows how to calculate the Fourier transform of a periodic or non-periodic signal?
4
136. Which equation shows how to calculate the Fourier transform of a non-periodic signal?
4
137. Which equation shows how to calculate the Fourier series complex coefficients for a periodic signal?
3
138. Which equation shows how to calculate the Fourier series cosine amplitudes for a periodic signal?
1
139. Which equation shows how to calculate the Fourier series sine amplitudes for a periodic signal?
2
 Author: lacythecoolest ID: 319542 Card Set: Networks pq set 3 Updated: 2016-05-05 00:58:56 Tags: networks Folders: Description: set 3 Show Answers: