The Fourier transform is a powerful tool often used in digital signal processing to convert signals from the time domain into the frequency domain and vice versa. Though the math complete this conversion is some complicated calculus, the basic concept of Fourier analysis is actually quite simple with the help of some examples.
A simple alternating current, such as one from a electric outlet in the US, typically runs 120 volts at 60 hertz. On a time domain graph, with time on the x-axis and voltage on the y-axis, this current would look like a sine wave with its magnitude alternating between -120 and +120 volts, hence an alternating current. If this current was analyzed after a Fourier transform, the signal can be graphed in the frequency domain, with frequency on the x-axis and voltage on the y-axis. The results are what is called the frequency components of the wave. Using the example of the alternating electrical current, there is only one line at a frequency of 60 hertz with an amplitude of 120 volts.
While this example of an alternating current may seem trivial, pictures and sound are represented using much more complicated signals. Possibly the most familiar tool that uses the frequency domain to better understand signals is a digital audio equalizer. When your favorite song is passed through an equalizer, it is actually using the Fourier transform to create a real time graph of what notes make up the sound! Hopefully this brief explanation of Fourier analysis has been interesting and enlightening. As a computer engineering student I have also had a some exposure to programming so I would like to you to consider this linked list implementation I made for a class.