Spectrum

input file : active soundfile

Spectral analysis characterizes the frequency content of a signal. Roughly speaking, an audio signal can be thought of as a combination of sinusoidal 'waves' (tones) of different amplitudes and frequencies. Spectrum analyzers decompose the signal into different frequency components in a very much the same way as a glass prism breaks up light into different colors.

Distribution of the signal power over frequency is called the power spectral density function of a signal or simply - its spectrum. The shape of a spectral graph contains important and useful information about the analyzed signal. A speech specialist, for example, can recognize the particular sound by examining the shape of its spectral density plot, e.g., by analyzing the number and localization of regions of spectrum emphasis (resonances, called formants) and deemphasis (antiresonances).

General remarks

Spectrum estimation

Spectral graphs