lab_noise_removal.pdf - Dr Chao Wang EEE203 Signals and Systems I Page 1 of 3 Lab Get Rid of That Noise Please In this lab your friend Bob will need

# lab_noise_removal.pdf - Dr Chao Wang EEE203 Signals and...

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Dr. Chao Wang EEE203 Signals and Systems I Page 1 of 3 Lab: Get Rid of That Noise Please In this lab, your friend Bob will need your help to recover a music recording corrupted by background noise. You need to help him get rid of the noise and restore the music piece, which was originally played by piano and drum. To complete this task, you need to get familiar with Fourier analysis, a powerful tool to analyze and manipulate the frequency content of a signal. Many audio effects such as filter effects, noise reduction, and equalization are based on this frequency domain method. In contrast, i n the “Let’s Make Music” lab, the simple audio editing functions such as changing speed/tempo, fading (one way of manipulating the amplitude envelope) and time reversing are all time-domain methods, i.e., they manipulate signals in the time domain. An efficient tool to perform Fourier analysis of discrete time sequences is Fast Fourier Transform (FFT). Explaining how it works and how it relates to Discrete Time Fourier Transform (DTFT) is beyond the scope of this course. Only examples on how to use the tool are discussed here. Let’s begin with analyzing the frequenc y content of the theme song “ Star Wars ” you made. Download the MATLAB script “fft_ star_wars .m” and copy the “ star_wars .wav” (the file you generated from the “Let’s Make Music” lab) to the same directory as the script. Run the script and observe the frequency

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