Computer science, computer science and more computer science. This was how my first year as a computer engineering major here at UCSB felt like. It was the only subject I took every quarter that dealt with my major. Although the courses were fun and challenging, I was hoping to have a course that dealt with circuits. Therefore, when I was searching for a professor to do research with during the summer of 2016,Professor James Buckwalter’s page caught my eye. He was working with millimeter-wave integrated circuits that would help increase data rates. It might not sound to exciting, but to me, helping increase the speed at which devices receive and transmit data sounded awesome. Additionally, integrated circuits sounded complex and I love a challenge.
After emailing Dr. Buckwalter, and setting up a time to meet up, I had a question bothering me. How was I supposed to help with integrated circuits if I had no previous knowledge of circuits in general? Having the question in the back of my head, I met with Dr. Buckwalter introduced myself and spoke to him about my interest in his research. Dr. Buckwalter then asked me what year I was in and what courses I had taken. After answering his questions, he said what I was most afraid he would say. Politely, explained to me that I had no experience in circuits and therefore it would be hard for me to help them in their research. However, he proposed another project, in which I would scan the radio spectrum to search for underutilized frequencies. After giving me further explanation, I was worried I was not going to like the project, but at the same time I had come in asking to work on something I had no knowledge of. Unconsciously, my mouth opened and agreed to the offer. I was worried, I had little information of what to expect, what I was going to learn, and what exactly I would be doing.
Fast forward into today, I am glad to have accepted Dr. Buckwalter’s offer because radio frequencies and the radio spectrum are much cooler than I expected. Each frequency is unique and therefore travels in its own “lane” carrying information. Determining which lanes are open is my goal for this summer. By doing this, we can then use the lanes that are left unused and make the spectrum more efficient, allowing data rates to increase. As you can see, I am actually doing something similar to what I initially wanted to do, except I am doing it through the radio spectrum.
During the three weeks I have been in the lab, I have learned more information than I expected in areas I did not expect. For example, I learned the two different ways in which phones transmit and receive signals, the path the waves follow when they are received by an antenna, and how the frequencies are extracted from the waves entering the antenna. I find the extraction of frequencies to be the most interesting.
It turns out that there is an equation called the Fourier Series that tells us that any function of time can be estimated by a series of sine and cosine waves with different frequencies. For instance, the square wave below is really just a combination of infinite amount of sine waves.
Having this in mind, when scanning a specific range of the radio spectrum, many different waves with different frequencies are added together along with noise. Now noise are random numbers with a certain variance added or subtracted to the signal. Therefore, once the signal is plotted onto a graph, it looks like Figure 2 and it is practically impossible to tell what frequencies are present in the range scanned.
However, when the Fast Fourier Series (FFT), a fast way to calculate the Fourier Series, is implemented to the function, we can visually see what frequencies are in the function by seeing the big spikes in the FFT graph (Figure 3). In the case below only frequency 10(Hz) is present and therefore is showed by two spikes in at 10(Hz) and -10(Hz).
Anyhow, what I am trying to say is that when choosing a research project, be open about it. It doesn’t have to be on something you are an expert on. It doesn’t even have to be related to your major. In my case, it was within my major, but it was new to me. Now, it is not so new and I spend hours working on my project, sometimes skipping meals because I am lost in the world of radio frequencies. Hence, I encourage all to pick a project outside the box, you never know what you will learn about the topic and about yourself.