MAE 334FE.01 - December 17, 2001- Page 1 Reminder: Lab #1 : Limitations of A/D conversion Lab #2 : Thermocouple, static and dynamic calibration Lab #3 : Conversion of work into heat Lab #4 : Pressure transducer, static and dynamic calibration Lab #5 : Pressure-volume measurements 1) While sampling a sinusoidal signal, we got the following pictures. Choose the output signal that contains the largest quatization error: Largest A, Least B (A)-1.5-0.50.51.50 10 20Time (seconds)Amplitude (volts)(B)-1.5-0.50.51.50 10 20Time (seconds)Amplitude (volts) (C)-1.5-0.50.51.50 10 20Time (seconds)Amplitude (volts)(D)-1.5-0.50.51.50 10 20Time (seconds)Amplitude (volts) 2) The sine wave in the above graphs has a frequency of a) 15 Hertz b) .15 Hertz c) 2/15 Radians/Second d) 30 Radians/Second e) 15 Radians/SecondMAE 334FE.01 - December 17, 2001- Page 2 3) The following equation is used to simulate a digitized sinusoidal signal. Y=sin(2fn/fs) Where f is signal frequency; fs is sampling frequency; n=1,2,3,…500. If f = 100 Hz and fs = 200 Hz what will the output signal looked like? C) 4) Same question as 2 above but now fs = 2000 Hz? A) 5) While performing Lab #1, Mr. Simpson insisted on setting the sampling frequency to an integer. This was necessary; a) to avoid aliasing b) to avoid amplitude ambiguity c) to resolve the waveform d) none of the above 6) Suppose the voltage range of your 8 bit ADC is +/- 5 Volts and the input signal gain is 5. What is the minimum voltage difference that can be detected with the A/D converter? a) 0.0078V b) 0.0039V c) 0.0195V d) 0.0039V 7) Which of the following never depends on the sampling rate? a) Frequency of the sampled signal b) Magnitude of the sampled signal c) Nyquist frequency of the input signal d) Shape of the sampled signal 8) If the Nyquist sampling criteria was satisfied for an input signal with a frequency of 1kHz, what was the sampling rate? a) 1kHz b) 200Hz c) 2kHz d) None of the above a) b) c)MAE 334FE.01 - December 17, 2001- Page 3 9) In Lab #1, the sample rate was held constant while the input signal frequency was increased. If the sample rate is set at 100 samples/sec., what is the maximum resolvable input frequency? a) 100Hz b) 200Hz c) 10Hz d) 50Hz 10) The time constant () of a thermocouple can be effected by the following factor(s)? a) size of the temperature step b) the direction of the temperature change c) the medium around the thermocouple d) all of the above 11) While working on the dynamic calibration during lab #2 report, you suddenly realize your data record stopped well before steady state was achieved and you have no information beyond that time point. You assume it doesn’t matter and proceed to use the equation: –ln{1-[(T-T0)/(Tf-T0)]}=(1/)*t to calculate the time constant () where T0 is the initial temperature and Tf is the final temperature. a) The value of  will not be effected b) The value of  will become smaller c) The value of  will become larger d) Only Tf will be effected 12) When performing static calibration of the thermocouple, you had five water cups of various temperatures. It was suggested to sample them randomly. a) To torment the students b) To prevent hysteresis. c) To minimize the standard error d) to minimize the effect of extraneous variables. 13) What type of thermocouple did we use in the lab? a) K-type Chomel-Aluminum b) J-type Iron-Constantan c) c) T-type Copper-Constantan d) G-type Tungsten-Rhodium 14) Which of the following will not affect the system properties in Lab #2? a) Medium (air or water) b) Temperature step c) Heat transfer coefficient d) Thermocouple typeMAE 334FE.01 - December 17, 2001- Page 4 15) Which of the following is not true based on the thermocouple we used? a) The thermocouple has a large time constant in air b) The Thermocouple properties depend on the experimental apparatus. c) If the room temperature rises, the reference junction temperature will also rise. d) The thermocouple has a finite mass 16) In Lab #2 we performed a static and dynamic calibration on a thermocouple. What was the main purpose for the dynamic calibration? a) To see the second order response of the thermocouple b) To determine the value of the time constant () c) To determine the damping ratio d) Both A and B e) Both B and C 17) What effect did the change of medium from water to air have on the value of the time constant () in lab #2? a) Increased  b) Decreased  c) Remained the same d) None of the above 18) The static calibration in lab #2 was conducted with what assumption regarding a cold junction compensator? a) It was not necessary since all the junctions were at room temperature. b) It was necessary and the results were skewed as a result of not incorporating a cold junction in the experiment. c) It was not necessary because the computer comes with cold junction compensation circuitry. d) Cold junctions are not necessary due to the advancements made in thermocouple technology. e) None of the above 19) You arrived to lab #3 a little late. Your partner is madly turning the drum trying to translate mechanical work into heat. The weight is of 5kg mass, the gravitational acceleration is 9.81m*s-2, and the diameter of the drum is 0.0465m. Your partner is turning the drum at a constant rate of 150 turns per minute. Can you help your partner calculate the rate of work done? a) 171.06 watts b) 17.90 watts c) 7.81 watts d) 5.70 wattsMAE 334FE.01 - December 17, 2001- Page 5 20) After performing a linear regression on temperature vs time for drum turning in lab #3, you found that the difference between the value of dT/dt predicted by dT/dt=P/C and the measured value is getting _______________ as the speed of the drum increases. Here T is temperature, P is input power, and C is heat capacity of the calorimeter. a) bigger b) smaller c) almost same 21) Which of the following properties are generally not desirable in a transducer? a) Large time constant b) High natural frequency c) Linearity d) A, B & C are all desirable e) A, B & C are not desirable 22) Which of the following does not indicate the linearity of a static calibration? a) The correlation coefficient, R b) Slope of the regression line c) The 95% confidence interval d) Standard error of