CPS-Lab / Mbed 2 deprecated Lab3

Dependencies:   mbed

Report.txt

Committer:
sks1
Date:
2018-02-09
Revision:
3:9956186744f0
Parent:
2:d457aead43f6

File content as of revision 3:9956186744f0:

Lab 3 Lab report
David Malone davmalon   
Samantha Smith sks1 

Results
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 
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 
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.

Difficulties
During the process of manipulating the sinewave example code, we ran into quite a few problems with the frequency of the wave. 
We were slightly confused initially on how to convert the period into frequency with the wait_us() function. 
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. 
To achive the actual frequency, one only has to divide the input frequency by 10 and pass that number to the wait_us function. 
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. 
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). 



How closely did your analysis match your measurements. What were the reasons for the differences? 

Our analysis and measurements did not match. This was due to the fact that we could not figure out how to crrectly convert the frequency in our code.
The amplitude of the blue sinewave did decrease as we increased frequency, but it did not do so as we calculated in our measurements.  


Filter Ideal Analysis and Measurements
Turned in on Canvas.