1. ECE Fun II Test 2 Review

2. -Fourier transform: U&Y, 5-7, 5-8, some of 5-10 o Definition o Properties o Basic functions -LTIC systems U&Y, 5-12 o Input/output in time and frequency domains o Sinusoids, periodic, and transient functions -Impulse Response U&Y, o Delta function properties o Convolution o h( t ) -Matlab, Tutorials and U&Y Appendix D o Basic syntax o Creating signals o Using the fft and conv functions o Plotting -Diodes A&L 16.1 thru 16.3 o Ideal Model o Constant forward voltage drop model o CFVD + Internal resistance model o Exponential model o Use of diodes with opamps. -MOSFETs A&L 7.1-7.4, 6.7 o Basic operation, terminals and polarities o Biasing o Small signal model J&B 13.8,13.10  Transconductance  Assumed linear range o Common source amplifier ECE Fun II Test 2 Topics

3. Given the following circuit values: R1=R4=1K, R2=R3=3K, V1=12V. Assuming the Constant Forward Voltage Drop model, (CFVD, V F =0.7V) which of the following is true? A.The diode current is approximately 0.5 mA. B.The diode current is approximately 1.0 mA C.The diode current is approximately 6.0 mA D.None of the other choices is correct.

4. Given the following circuit values: R1=R4=1K, R2=R3=3K, V1=12V. Assuming the Constant Forward Voltage Drop model, (CFVD, V F =0.7V) which of the following is true? A.The diode current is approximately 0.5 mA. B.The diode current is approximately 1.0 mA C.The diode current is approximately 6.0 mA D.None of the other choices is correct.

5. If R2=R3=1K, R4=R1=1000K, V1=10.7 V, and assuming the CFVD model, which of the following is true? A.The diode current is approximately 5 mA. B.The diode current is approximately 2.5 mA. C.The diode is not conducting. D.None of the other choices is correct.

6. If R2=R3=1K, R4=R1=1000K, V1=10.7 V, and assuming the CFVD model, which of the following is true? A.The diode current is approximately 5 mA. B.The diode current is approximately 2.5 mA. C.The diode is not conducting. D.None of the other choices is correct.

7. Which of the following best describes the display? A.The system settings for the vertical scale should be increased, i.e. more volts per division. B.The system settings for the horizontal scale should be decreased, i.e. less time per division. C.Both the vertical and horizontal scales are set incorrectly. D.None of the other choices is correct.

8. Which of the following best describes the display? A.The system settings for the vertical scale should be increased, i.e. more volts per division. B.The system settings for the horizontal scale should be decreased, i.e. less time per division. C.Both the vertical and horizontal scales are set incorrectly. D.None of the other choices is correct.

9. If the setting of the signal generator is 2 V P-P and the oscilloscope displays a 0.1 V amplitude signal, which of the following is true. A.The probe setting is at 10X but the VB setting is at 1X. B.The signal generator is set at 10X, and the probe is set to 1X. C.The signal generator is set to 10X and the probe is set to 10X. D.None of the other choices is correct.

10. If the setting of the signal generator is 2 V P-P and the oscilloscope displays a 0.1 V amplitude signal, which of the following is true. A.The probe setting is at 10X but the VB setting is at 1X. B.The signal generator is set at 10X, and the probe is set to 1X. C.The signal generator is set to 10X and the probe is set to 10X. D.None of the other choices is correct.

11. You are given the following circuit in the figure. Assume that the op amp has infinite gain, unlimited bandwidth, but is bounded in output by VCC and VEE, where VCC is the most positive voltage in the system and VEE is the most negative voltage in the system. A B C D

12. A B C D

13. Suppose a simple system, such as a channel from a cell tower to a cell phone, has impulse response as shown in the figure below. This impulse response resulted from one signal path with delay t0=0.125 µs. The input to the system is the sinusoid: x(t)=3sin2πf 0 t where f 0 =1 MHz. What could the output of the system, i.e., the signal received at the cell phone, be? A.A sinusoid with frequency 1/t 0 Hz. B.A sinusoid with frequency 2π/t 0 Hz. C.A sinusoid with frequency 2πf 0 Hz. D.None of the above.

14. Suppose a simple system, such as a channel from a cell tower to a cell phone, has impulse response as shown in the figure below. This impulse response resulted from one signal path with delay t0=0.125 µs. The input to the system is the sinusoid: x(t)=3sin2πf 0 t where f 0 =1 MHz. What could the output of the system, i.e., the signal received at the cell phone, be? A.A sinusoid with frequency 1/t 0 Hz. B.A sinusoid with frequency 2π/t 0 Hz. C.A sinusoid with frequency 2πf 0 Hz. D.None of the above.

15. Suppose a simple system, such as a channel from a cell tower to a cell phone, has impulse response as shown in the figure below. This impulse response resulted from one signal path with delay t0=0.125 µs. The input to the system is the sinusoid: x(t)=3sin2πf 0 t where f 0 =1 MHz.

16. Suppose a simple system, such as a channel from a cell tower to a cell phone, has impulse response as shown in the figure below. This impulse response resulted from one signal path with delay t0=0.125 µs. The input to the system is the sinusoid: x(t)=3sin2πf 0 t where f 0 =1 MHz.

17. For the system described below determine if it is linear and time invariant. Rubric: A: Yes B: No C: Cannot tell  A system with input x(t) and output y(t)= x(0) + x(t). Linear? Time invariant?

18. For the system described below determine if it is linear and time invariant. Rubric: A: Yes B: No C: Cannot tell  A system with input x(t) and output y(t)= x(0) + x(t). Linear? A Time invariant?

19. For the system described below determine if it is linear and time invariant. Rubric: A: Yes B: No C: Cannot tell  A system with input x(t) and output y(t)= x(0) + x(t). Linear? A Time invariant? B

20. For the system described below determine if it is linear and time invariant. Rubric: A: Yes B: No C: Cannot tell  An ordinary light switch, where the input is the force with which the switch is pressed, and the output is the amount of light produced. Linear? Time invariant?

21. For the system described below determine if it is linear and time invariant. Rubric: A: Yes B: No C: Cannot tell  An ordinary light switch, where the input is the force with which the switch is pressed, and the output is the amount of light produced. Linear? B Time invariant?

22. For the system described below determine if it is linear and time invariant. Rubric: A: Yes B: No C: Cannot tell  An ordinary light switch, where the input is the force with which the switch is pressed, and the output is the amount of light produced. Linear? B Time invariant? A

23.  A second order passive RLC circuit driven by an input voltage Vin(t) and measuring as output the voltage drop across the capacitor. Assume the components have zero energy stored before the input is applied. For the system described below determine if it is linear and time invariant. Rubric: A: Yes B: No C: Cannot tell Linear? Time invariant?

24.  A second order passive RLC circuit driven by an input voltage Vin(t) and measuring as output the voltage drop across the capacitor. Assume the components have zero energy stored before the input is applied. For the system described below determine if it is linear and time invariant. Rubric: A: Yes B: No C: Cannot tell Linear? A Time invariant?

25.  A second order passive RLC circuit driven by an input voltage Vin(t) and measuring as output the voltage drop across the capacitor. Assume the components have zero energy stored before the input is applied. For the system described below determine if it is linear and time invariant. Rubric: A: Yes B: No C: Cannot tell Linear? A Time invariant? A

26. Let the input x(t) and impulse response h(t) to a linear time invariant system be: Determine whether each of the following statements about the output of the system y(t) is true (A) or false (B): y(t) is even symmetric y(t) = 0 for all t < 0 The maximum value for y(t) is 9 y(t) is piecewise linear The duration of the non-zero portion of y(t) is 6 s.

27. Let the input x(t) and impulse response h(t) to a linear time invariant system be: Determine whether each of the following statements about the output of the system y(t) is true (A) or false (B): y(t) is even symmetric F y(t) = 0 for all t < 0 The maximum value for y(t) is 9 y(t) is piecewise linear The duration of the non-zero portion of y(t) is 6 s.

28. Let the input x(t) and impulse response h(t) to a linear time invariant system be: Determine whether each of the following statements about the output of the system y(t) is true (A) or false (B): y(t) is even symmetric F y(t) = 0 for all t < 0 F The maximum value for y(t) is 9 y(t) is piecewise linear The duration of the non-zero portion of y(t) is 6 s.

29. Let the input x(t) and impulse response h(t) to a linear time invariant system be: Determine whether each of the following statements about the output of the system y(t) is true (A) or false (B): y(t) is even symmetric F y(t) = 0 for all t < 0 F The maximum value for y(t) is 9 T y(t) is piecewise linear The duration of the non-zero portion of y(t) is 6 s.

30. Let the input x(t) and impulse response h(t) to a linear time invariant system be: Determine whether each of the following statements about the output of the system y(t) is true (A) or false (B): y(t) is even symmetric F y(t) = 0 for all t < 0 F The maximum value for y(t) is 9 T y(t) is piecewise linear F The duration of the non-zero portion of y(t) is 6 s.

31. Let the input x(t) and impulse response h(t) to a linear time invariant system be: Determine whether each of the following statements about the output of the system y(t) is true (A) or false (B): y(t) is even symmetric F y(t) = 0 for all t < 0 F The maximum value for y(t) is 9 T y(t) is piecewise linear F The duration of the non-zero portion of y(t) is 6 s. T

32. Which of the following is true? A.By displaying a large number of cycles, the FFT math function will give a good approximation of the Fourier series for the displayed signal. B.In order to get a good approximation of the Fourier series, it will be necessary to decrease the horizontal scale until no more than 3 cycles of the signal are displayed. C.In order to get a good approximation of the Fourier series for the displayed signal, it will be necessary to decrease the vertical scale, i.e. fewer volts per division such that the peaks of the signal extend beyond the screen limits in order to minimize the effects of amplitude variations. D.None of the other choices is correct.

33. Which of the following is true? A.By displaying a large number of cycles, the FFT math function will give a good approximation of the Fourier series for the displayed signal. B.In order to get a good approximation of the Fourier series, it will be necessary to decrease the horizontal scale until no more than 3 cycles of the signal are displayed. C.In order to get a good approximation of the Fourier series for the displayed signal, it will be necessary to decrease the vertical scale, i.e. fewer volts per division such that the peaks of the signal extend beyond the screen limits in order to minimize the effects of amplitude variations. D.None of the other choices is correct.

34. A D C B

35. A D C B

36. A D C B

37. A D C B

38. A D C B

39. A D C B

40. A D C B

41. A D C B

42. Assume that the circuit is operating in the saturated region for Q1. Which of the following is true? A.If the value of RD is reduced by a factor of 2, the voltage gain will go down, approximately by 2 but the operating region will not change. B.If the value of RD is increased by a factor of 2 the voltage gain will increase by 2 and the operating region will not change. C.If R1 is decreased the operating region will not change. D.None of the other choices is true.

43. Assume that the circuit is operating in the saturated region for Q1. Which of the following is true? A.If the value of RD is reduced by a factor of 2, the voltage gain will go down, approximately by 2 but the operating region will not change. B.If the value of RD is increased by a factor of 2 the voltage gain will increase by 2 and the operating region will not change. C.If R1 is decreased the operating region will not change. D.None of the other choices is true.

44. Assume that RD is 2K, RL is 100K and the overall voltage gain is 3 with a gm of 0.05S. The frequency of V2 is 100KHZ and the circuit is operating in mid-band and the small signal model applies. Which of the following is true? A.The voltage gain will be relatively stable over significant changes in the values of the circuit parameters for Q1. B.RS affects the value of the low-pass breakpoint associated with C2. C.If R1 is decreased, the value of the gain will decrease, but the breakpoint frequencies for the overall circuit will not be affected. D.None of the other answers is correct.

45. Assume that RD is 2K, RL is 100K and the overall voltage gain is 3 with a gm of 0.05S. The frequency of V2 is 100KHZ and the circuit is operating in mid-band and the small signal model applies. Which of the following is true? A.The voltage gain will be relatively stable over significant changes in the values of the circuit parameters for Q1. B.RS affects the value of the low-pass breakpoint associated with C2. C.If R1 is decreased, the value of the gain will decrease, but the breakpoint frequencies for the overall circuit will not be affected. D.None of the other answers is correct.

46. Using the values from the previous question, assume that a 10000 µF capacitor is placed in parallel with RS. Which of the following is true? A.The voltage gain would increase to approximately 100, but the input signal would have to be reduced to stay in the range of operation for which the small signal model would apply. B.The voltage gain would decrease dramatically as this capacitor would short the signal to ground. C.The voltage gain would be unaffected, but the Q point would shift towards the triode region. D.None of the other choices is correct.

47. Using the values from the previous question, assume that a 10000 µF capacitor is placed in parallel with RS. Which of the following is true? A.The voltage gain would increase to approximately 100, but the input signal would have to be reduced to stay in the range of operation for which the small signal model would apply. B.The voltage gain would decrease dramatically as this capacitor would short the signal to ground. C.The voltage gain would be unaffected, but the Q point would shift towards the triode region. D.None of the other choices is correct.

52. Can this frequency response be obtained exactly by using standard circuit elements? A.Yes B.No

53. Can this frequency response be obtained exactly by using standard circuit elements? A.Yes B.No

60. The first four lines of a Matlab script are as follows: dt=0.01; t=0:dt:3; x=sin(2*pi*t); X=fft(x); What command to follow produces the following output: A.plot(X) B.plot(phase(X)) C.plot(abs(X)) D.plot(abs(x))

61. The first four lines of a Matlab script are as follows: dt=0.01; t=0:dt:3; x=sin(2*pi*t); X=fft(x); What command to follow produces the following output: A.plot(X) B.plot(phase(X)) C.plot(abs(X)) D.plot(abs(x))

62. The first four lines of a Matlab script are as follows: dt=0.01; t=0:dt:3; x=sin(2*pi*t); X=fft(x);

63. The first four lines of a Matlab script are as follows: dt=0.01; t=0:dt:3; x=sin(2*pi*t); X=fft(x);

64. The first four lines of a Matlab script are as follows: dt=0.01; t=0:dt:3; x=sin(2*pi*t); X=fft(x);

65. The first four lines of a Matlab script are as follows: dt=0.01; t=0:dt:3; x=sin(2*pi*t); X=fft(x);