A spectrogram displays a signal's changing local frequency spectrum, usually by color proportional to squared short-time Fourier transform magnitude. With window function , one convention isThe window selects a neighborhood of time before taking its Fourier transform. A sinusoid gives a persistent frequency ridge, while a brief pulse spreads across frequencies and occupies a short time range.
A longer window separates nearby persistent frequencies more clearly but mixes events across a longer interval. A shorter window localizes transients but broadens their spectral features. Changing the window function changes this tradeoff and the spectral leakage. Zero padding can sample the displayed frequency curve more finely; it does not add observed data or restore the resolution lost through a short measurement interval. The phase is discarded in the plotted squared magnitude, so the spectrogram should not be confused with a complete set of complex transform coefficients.
A spectrogram is a visual representation of the spectrum of frequencies in a signal as it varies with time. It is commonly used in various fields such as audio processing, speech analysis, music analysis, and signal processing. The spectrogram is generated by taking a time-domain signal and applying a Fourier transform to break it down into its frequency components over time. The result shows how the frequency content of the signal changes over time, typically with: - The horizontal axis representing time.
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