July 2016
Beginner to intermediate
462 pages
9h 14m
English
Content preview from Python Data Analysis Cookbook
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Analyzing signals with the discrete cosine transform
The discrete cosine transform (DCT) is a transform similar to the Fourier transform, but it tries to represent a signal by a sum of cosine terms only (refer to equation 6.11). The DCT is used for signal compression and in the calculation of the mel frequency spectrum, which I mentioned in the Analyzing the frequency spectrum of audio recipe. We can convert normal frequencies to the mel frequency (a frequency more appropriate for the analysis of speech and music) with the following equation:
The steps to create the mel frequency spectrum are not complicated, but there are quite a few of them. The ...