CPS-Lab / Mbed 2 deprecated Lab3

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Dependencies:   mbed

Report.txt@2:d457aead43f6, 2018-02-09 (annotated)

Committer:
sks1
Date:
Fri Feb 09 17:18:15 2018 +0000
Revision:
2:d457aead43f6
Parent:
1:5192dafaecad
Child:
3:9956186744f0
added results

Who changed what in which revision?

UserRevisionLine numberNew contents of line
davmalon 1:5192dafaecad 1 Lab 3 Lab report
davmalon 1:5192dafaecad 2 David Malone davmalon
davmalon 1:5192dafaecad 3 Samantha Smith sks1
davmalon 1:5192dafaecad 4
davmalon 1:5192dafaecad 5 Results
sks1 2:d457aead43f6 6 In this lab, we created a low pass filter using the given equation and a cutoff frequency of 200 Hz. We chose to use a 0.1 uF capacitor and, using the equation, calculated that we should
sks1 2:d457aead43f6 7 use a resistor value of about 8200 ohms. We were then able to connect the low pass filter onthe breadboard and generate a sinewave of 100 Hz with an
sks1 2:d457aead43f6 8 amplitude of 1 V. When stepping the sinewave frequency by 10 Hz each time, we were about the see that the blue wave became smaller as the frequency increased.
davmalon 1:5192dafaecad 9
davmalon 1:5192dafaecad 10 Difficulties
davmalon 1:5192dafaecad 11 During the process of manipulating the sinewave example code, we ran into quite a few problems with the frequency of the wave.
davmalon 1:5192dafaecad 12 We were slightly confused initially on how to convert the period into frequency with the wait_us() function.
davmalon 1:5192dafaecad 13 Eventually we had realized that the function operated in miliseconds and the frequency we were giving the function was actually a delay of 1ooms and not 100hz/samples per second.
davmalon 1:5192dafaecad 14 To achive the actual frequency, one only has to divide the input frequency by 10 and pass that number to the wait_us function.
davmalon 1:5192dafaecad 15 We also had an issue with how we originally connected our circuit which caused a few problems. One issue that stemmed from this was that we chose a capacitor with a high capacitance that disrupted the form of our sinewave.
davmalon 1:5192dafaecad 16 We simply chose another capacitor, at .1 microferrats. and this fixed our problem (we swapped out the resistor to reflect this change in our circuit for our freuency cutoff value).
davmalon 1:5192dafaecad 17
davmalon 1:5192dafaecad 18
davmalon 1:5192dafaecad 19
davmalon 1:5192dafaecad 20 How closely did your analysis match your measurements. What were the reasons for the differences?
davmalon 1:5192dafaecad 21
davmalon 1:5192dafaecad 22 Filter Ideal Analysis
davmalon 1:5192dafaecad 23
davmalon 1:5192dafaecad 24
davmalon 1:5192dafaecad 25 Filter Measurements