1. What was the time delay from when the wave was generated at the speaker to when it first reached the microphone using the baseline signal in milliseconds? (HINT: A simple method for finding the time values is plotting the input and baseline signal versus time and using the data cursor. More rigorous methods can be used if you like. The time delay should be between 0.5 and 1 ms.)
2. What was the time delay from when the wave was generated at the speaker to when the reflection from the target reached the microphone in milliseconds ? (HINT: Subtract the baseline signal from the target signal. The time delay should be between 1.5 and 2 ms.)
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Write My Essay For Me3. Create a figure similar to Figure 2 showing the input signal, the raw target signal (target_V), the baseline signal, and the reflection signal (target_V-baseline_V) versus time in milliseconds. (NOTE: For the SONAR calculations we are mainly concerned with the time the signal takes to reach the microphone, with the voltage of the signal only being used to determine the time of features of interest. By offsetting each of the signals in the figure, it allows for easier visual comparison. You can use the command set(gca,’YTickLabel’,[]) to turn off the values on the y-axis of your figure so that only the time aspect of the signal is emphasized. Additionally, for your reports you may want to think about how you can add labels to features or points of interests, though it is not required here.)
SONAR – 1 Degree of Freedom
4. If the speed of sound was found to be 344 m/s, what is the distance from speaker sound source to the microphone in meters?
5. What is the distance from speaker sound source to the target in the first location in meters? (HINT: It should be between 0.3-0.5 m.)
SONAR – 2 Degrees of Freedom
In the previous case, the target object was known to be on the axis of the speaker and could be located by just calculating the distance (1 degree of freedom). In most SONAR applications the direction to the object will be unknown (3 degrees of freedom). For this lab, the target object will be at approximately the same height as the speaker, and therefore only two spatial coordinates must be solved (2 degrees of freedom). Since we can only measure time delay in our signals with our system, two different reflection measurements must be made to solve for the target coordinates. This will be accomplished by moving the microphone to known directions from the speaker axis (±30⁰).
6. In the figure below, draw the path of the sound (speaker-object-microphone) on the figure above, for both microphones.
7. If the object is located at and the speaker is located at origin, what is the equation for the distance that the sound traveled from the speaker to the object?
8. If the object is located at and the microphone at position A is located at , what is the equation for the distance that the sound traveled from the object to position A?
9. What is the total distance the sound traveled from the origin to the object and then to the microphone at position A?
10. Similarly, what is the total distance the sound traveled from the origin to the object and then to the microphone at position B, ?
“SONAR2DOF.mat” contains a sample set of 2 DOF SONAR data with the input signal to the speaker (input_V), the baseline signal at microphone position A without the object (baselineA_V), the target signal at microphone position A with the object (targetA_V), the baseline signal at microphone position B without the object (baselineB_V), the target signal at microphone position B with the object (targetB_V), and the time for each signal (time_s). Using analysis of the signals similar to the 1 DOF case, this data can to be used to determine the distances traveled by the sound to the microphone in positions A and B. For your calculations assume that the measured speed of sound is 344 m/s.
11. What are the distances to the microphone in positions A and B using the respective baseline data in meters? (HINT: Both are between 0.25 and 0.35 meters.)
12. What are the coordinates of the microphone at position A and B in meters if and?
13. What is the total distance that the reflective sound traveled from the origin to the object and then to the microphone at positions A and B in meters? (HINT: Both are between 1.4 and 1.7 meters.)
14. Using the calculated microphone coordinates and distances from problems 12 and 13, the only unknowns now in the distance equations from problems 9 and 10 are the object coordinates, . What are the coordinates of the target object in meters? (HINT: Try using the vpasolve() function in MATLAB to numerically solve the problem. Use the online help resources if you are unfamiliar with the function. There are multiple numerical solutions to this problem, but only one physical one. You may need to supply a reasonable guess to the solver and should verify the answer it returns makes physical sense.)
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