Hello internet homies,

This will be my last post for some time as I’m headed to California on Tuesday until August 19th. I’ll return to work from the 25th to the 29th and by that time I hope to know whether or not I’ll be continuing to work at the Plasma Lab during the Fall semester. During this week I encountered lots of unforeseen trouble with getting the frequency controlled resistor set-up that I designed to work with the 90 degree shifter that I made. However, on Wednesday afternoon I was able to get data out for the first time, which was hugely encouraging for me as it meant that my project will function correctly once I figure out how to recreate this initial victory on the circuit board pictured in the last blog post.

I’m including the two plots in this post, the first shows the frequency response of the circuit with respect to frequency of the incoming signal, and as can hopefully be seen, it is a very flat response.
phase_v_freq

This phase response was something I had before, but what really made my day when I finally got it to work and pleased professor Volpe was the following graph of gain response versus frequency of the incoming signal.

gain_v_freq

While this should be as flat as the first plot, this response is much better than the response without the correctly functioning frequency controlled resistor that I programmed. With a little reprogramming, I am confident that I will be able to level out the higher frequency end of the second plot, bringing the goal of a circuit that has both flat phase response and flat gain response to incoming signals.

While professor Volpe was very pleased with these results, he also had some news that complicates the course that this project is going to take. He said that he realized only recently that the way I was setting up my circuit could only handle one signal at a time, while the signal that actually comes out of the plasma will have upwards of ten signals superimposed over one another. This makes the problem considerably more complex, and I’m going to have to find another method by which to isolate each of those signals and apply different resistances accordingly. I have some ideas about how to do this, but they definitely will not be ready by the end of the month, so that raises the issue of me working in the lab for the duration of the semester, which I would consider a great privilege. For this week though, a victory is a victory and the complicated nature of the next steps in this project will be something that I look into when I return from my glorious time off in California.

That’s all for now internet, stay beautiful

Lucas

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