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Time-Frequency Analysis

Spectrogram, cross-spectrogram, synchrosqueezing, reassignment, Wigner-Ville, Hilbert-Huang, kurtogram

Signal Processing Toolbox™ provides functions and apps that enable you to visualize and compare time-frequency content of nonstationary signals. Compute the short-time Fourier transform and its inverse. Obtain sharp spectral estimates using reassignment or Fourier synchrosqueezing. Plot cross-spectrograms, Wigner-Ville distributions, and persistence spectra. Extract and track time-frequency ridges. Estimate instantaneous frequency, spectral kurtosis, and spectral entropy. Perform data-adaptive time-frequency analysis using empirical mode decomposition and the Hilbert-Huang transform.


Signal AnalyzerVisualize and compare multiple signals and spectra
Signal LabelerLabel signal attributes, regions, and points of interest


emdEmpirical mode decomposition
fsstFourier synchrosqueezed transform
ifsstInverse Fourier synchrosqueezed transform
hhtHilbert-Huang transform
instfreqEstimate instantaneous frequency
kurtogramVisualize spectral kurtosis
pkurtosisSpectral kurtosis from signal or spectrogram
pentropySpectral entropy of signal
pspectrumAnalyze signals in the frequency and time-frequency domains
spectrogramSpectrogram using short-time Fourier transform
xspectrogramCross-spectrogram using short-time Fourier transforms
stftShort-time Fourier transform
stftmag2sigSignal reconstruction from STFT magnitude
iscolaDetermine whether window-overlap combination is COLA compliant
istftInverse short-time Fourier transform
tfridgeTime-frequency ridges
vmdVariational mode decomposition
wvdWigner-Ville distribution and smoothed pseudo Wigner-Ville distribution
xwvdCross Wigner-Ville distribution and cross smoothed pseudo Wigner-Ville distribution


Time-Frequency Gallery

Examine the features and limitations of the time-frequency analysis functions provided by Signal Processing Toolbox.

Practical Introduction to Continuous Wavelet Analysis (Wavelet Toolbox)

This example shows how to perform and interpret continuous wavelet analysis.

FFT-Based Time-Frequency Analysis

Display the spectrogram of a linear FM signal.

Instantaneous Frequency of Complex Chirp

Compute the instantaneous frequency of a signal using the Fourier synchrosqueezed transform.

Detect Closely Spaced Sinusoids

Compute the instantaneous frequency of two sinusoids using the Fourier synchrosqueezed transform. Determine how separated the sinusoids must be for the transform to resolve them.

Radar Waveform Classification Using Deep Learning (Phased Array System Toolbox)

This example shows how to classify radar waveform types of generated synthetic data using the Wigner-Ville distribution (WVD) and a deep convolutional neural network (CNN).

Pedestrian and Bicyclist Classification Using Deep Learning (Phased Array System Toolbox)

This example shows how to classify pedestrians and bicyclists based on their micro-Doppler characteristics using a deep learning network and time-frequency analysis.

Featured Examples