# Networks pq set 3

 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 The MATLAB program fft935.m uses the command X = fft(x,N) where ___ is the variable containing a bunch of complex numbers. X The MATLAB program fft935.m uses the command X = fft(x,N) where ___ is the function that performs the Fourier Transform. fft The MATLAB program fft935.m uses the command X = fft(x,N) where ___ is the number of values of x and X. N . The MATLAB program fft935.m uses the command X = fft(x,N) where ___ is the time-domain signal x 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 Ex935 requires the MATLAB program fft935.m which computes and plots the Fourier Transform of x(t). true Ex935 requires the MATLAB program fft935.m implements the Fourier Transform using a specific implemention: fft - Fast Fourier Transform Ex935 requires the MATLAB program fft935.m which is also called a script Ex935 generates a time-domain signal where the signal-to-noise ratio is nearly 0.3 Ex935 generates a time-domain signal with 3 sinusoids and noise with a peak-to-peak amplitude of nearly 60 Ex935 generates a time-domain signal with 3 sinusoids with a peak-to-peak amplitude of nearly 16 Ex935 generates a time-domain signal with 3 sinusoids that have ____ frequencies and _____ amplitudes. different, different Ex935 generates a time-domain signal containing _____ values. 4096 Ex935 generates a time-domain signal containing _____. noise or random numbers, which are the same thing Ex935 generates a time-domain signal containing ____ sine components. 3 Ex935 is primarily about the Fourier Transform 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) 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) For a Bode gain of -20 dB, the system numeric gain at that frequency is 0.1 A Bode plot shows output and input sine wave ratios over a wide range of frequencies. true A Bode plot shows the sinusoidal output signal for a linear system relative to the sinusoidal input signal. true A high-pass Bode phase plot shows nearly _____ phase at low frequency and nearly ______ phase at high frequency. 90, 0 A high-pass Bode gain plot shows _____ gain at low frequency and ______ gain at high frequency. low, high The Bode phase plot is phase in degrees vs frequency in rad/sec The Bode gain plot is gain in dB vs frequency in rad/sec Both Bode plot gain and phase plots are ______ plots. semilog Both Bode plot gain and phase axes are linear scales In both Bode plot gain and phase axes, _____ axes are different in both plots. vertical The Bode plot frequency axis is a log scale The Bode plot frequency axis is the horizontal axis and is the same for both plots The bottom Bode plot is system phase vs frequency The top Bode plot is system gain vs frequency A Bode plot is two plots A Bode plot is a description of a linear system Vout/Vin = -R2/R1 is a number (e.g. -3), therefore Vout = -3*Vin Vout/Vin = -R2/R1 is a number and is also called the ____ of the inverting opamp configuration gain An ameteur mastake occurs in the audio portion of the video since KVL is mentioned, but KCL should have been stated. t/f true The power-supply ground for the internal opamp circuit (not the noninverting input) is not connected to the opamp The non-inverting input (positive input port) is grounded in the inverting opamp configuration because 0 volts is desired at the inverting input. The positive and negative supply voltages in the opamp video are present but not shown Negative in the inverting opamp transfer function (-R2/R1) means both of thesenegative input produces positive output voltage positive input produces negative output voltage The transfer function (Vout/Vin) of an inverting opamp configuration like in the video is -Z2(s)/Z1(s) The transfer function (Vout/Vin) of the inverting opamp configuration in the video is -R2/R1 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 The ideal-opamp current (ma) to the signal-input ports is about 0 How many signal output ports does the opamp have? 1 The opamp has ____ power ports (voltage-supply inputs). 2 The opamp has ____ signal-input ports. 2 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 The opamp with its many external configurations is one of the most useful electronic circuits. t/f true A transfer function is a _______-domain concept. complex-vaiable s A transfer function is a ratio of two s-domain signals (output divided by input) A transfer function is a linear-system ____-domain I/O relationship for which input and output signals ______. s, may be unknown Voltage and current are common examples of ______ in ______ engineering. signals, electrical Position, velocity, acceleration, pressure, temperature, humidity are common examples of ____ in ____ engineering signals, mechanical Common electrical and mechanical signals can be expressed in the time domain and the s-domain The linear-system transfer function can be determined without knowing input or output signals. t/f true The linear-system transfer function (TF) can be written without knowing input or output signals, and the TF = output/input. t/f true TF1 and TF2 are in series. TF= combination of both. TF= TF1*TF2 TF1 and TF2 are in parellel. TF= combination of both. TF= TF1+TF2 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) The TF=(s+a)/(s+b) has one real pole at s=-b 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 The TF=25/(s^2+6s+25) = 25/( (s+3)^2 + 4^2 ) is an example of a 2nd-order TF 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 In the TF=wn^2/(s^2 + 2*zeta*wn*s + wn^2), wn is undamped natural frequency in rad/sec In the TF=wn^2/(s^2 + 2*zeta*wn*s + wn^2), zeta is damping ratio with no units In the TF=25/(s^2+6s+25), the undamped natural frequency is _____ rad/sec. 5 In the TF=25/(s^2+6s+25), the damping ratio is 0.6 Damping ratio (zeta) and undamped natural frequency (wn) are ____-domain concepts. s Specific values of damping ratio (zeta) and undamped natural frequency (wn) ___ related to time-domain concepts. are 4/0 is infinity -1.1E-15/0 is negative infinity The calculator reading (1.2E-14 to 1.2E-15) should be interpreted as a value of zero due to roundoff at calculator limits 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. Can a bunch of sine and cosine functions be added to approximate any function that is periodic or not periodic? yes Can a bunch of sine and cosine functions be added to make any periodic function? yes Can a bunch of sine and cosine functions be added to make a square-wave function? yes Can a bunch of sine and cosine functions be added to make a triangle function? yes The second-Fourier-Series component has a frequence that is ____ the fundamental frequency. exactly two times The first Fourier Series component is called the fundamental or first harmonic. true The Fourier Series components are also called harmonics. true The Fourier Series componenents are all sinusoids If the time-domain signal x(t) is not periodic, the X(f) will be the Fourier Transform. true If the time-domain signal x(t) is periodic, the X(f) will be the Fourier Series. true X(f) is the _____ of the time-domain signal x(t). Fourier Transform or Fourier Series The diagram that shows (human voice - electronic signal - EM wave - electronic signal - human voice) introduces signal processing Which domain is used when making a Bode plot? jw domain Bode Plots deal with ______ input and output signals. sinusoidal Time invariant in a LTI system means a time delay of the input signal results in ______ time delay of the output signal. the same Which of the following is true about a LTI system? both of theseThe signals scaleTwo times the input signal results in two times the output signal. LTI stands for Linear and Time Invariant The delay TF has Bode-gain that _____ as frequency increases. remains constant The delay has Bode-phase that _____ as frequency increases. decreases The second-order lag has Bode-gain slope of ____ after the corner -40dB/decade The integrator has Bode-gain slope of ____ over all frequencies. -20 dB/decade The differentiator has Bode-gain slope of ____ over all frequencies. 20dB/decade The first-order lag has a Bode-gain slope of _____ after the corner. -20dB/decade The first-order lead has a Bode-gain slope of _____ after the corner. 20dB/decade G(s) = exp(-a*s) delay G(s) = s differentiator G(s) = 1/s integrator G(s) = a/(s^2 + b*s + w1^2) second-order lag (s) = a / ( (s+w1) * (s+w2) ) double lag G(s) = a/(s+w1) first-order lag G(s) = a*(s+w1) first-order lead G(s)=(s+a)/(s+b), and in Bode-plot form, G(s)= (a/b)(1+s/a)/(1+s/b) G(s)=1/(s^2+a*s+b), and in Bode-plot form, G(s)= (1/b)/(1+a*s/b+s^2/b) G(s)=1/((s+b)(s+a)), and in Bode-plot form, G(s)= (1/(a*b))/((1+s/b)(1+s/a)) G(s)=1/(s(s+a)), and in Bode-plot form, G(s)= (1/a)/(s(1+s/a)) G(s)=1/((s+b)(s+a)), and in Bode-plot form, G(s)= (1/(a*b))/((1+s/b)(1+s/a)) The system TF must be written in _____ in order to manually sketch asymptotic Bode plots factored-polynomial form The system TF must be written in _____ in order to manually sketch asymptotic Bode plots system transfer functions Deviations of asymptotic Bode plots from actual Bode plots occur at the corners Asympotic Bode plots are straight-line approximations A delta function has _____ height and _____ width and _____ area. infinite, zero, unit The width of the rectangular pulse (hat function) is tau The height of the rectangular pulse (hat function) is A The integral from -infinity to +infinity of delta(t) is 1 Equations 6,7 and 8 were derived from equation 4, which is _____ the capability of the student of beginning calculus. well within Equations 6,7 and 8 were derived from equation 4 Equations 6,7 and 8 have something in common: no imaginary part Equation 7 is easily visualized as most like 1/f^2 Equation 8 is the Fourier transform of a delta function Equation 7 is the Fourier transform of a two-sided exponential Equation 6 is a sinc function Equation 6 is the Fourier transform of a pulse or hat function X_bar_n in equation 3 is ____ and X_bar(f) in equation 4 is a ____. discrete set, continuous function X_bar_n in equation 3 and X_bar(f) in equation 4 are both complex true The period of the periodic signal in equations 1-3 is T An, Bn, and Xn are _____ in number theoretically, and _____ in practice. infinite, small Equation 4 is theoretically interesting, but is not practical because of the infinite limits. false Equation 4 is theoretically interesting, but is not practical because of the infinite limits. x(t) Which equation shows how to calculate the Fourier transform of a periodic or non-periodic signal? 4 Which equation shows how to calculate the Fourier transform of a non-periodic signal? 4 Which equation shows how to calculate the Fourier series complex coefficients for a periodic signal? 3 Which equation shows how to calculate the Fourier series cosine amplitudes for a periodic signal? 1 Which equation shows how to calculate the Fourier series sine amplitudes for a periodic signal? 2 Authorlacythecoolest ID319542 Card SetNetworks pq set 3 Descriptionset 3 Updated2016-05-05T00:58:56Z Show Answers