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Time-Frequency Analysis

Spectrogram, synchrosqueezing, reassignment, Wigner-Ville, time-frequency marginals, data-adaptive methods

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, instantaneous bandwidth, spectral kurtosis, and spectral entropy. Perform data-adaptive time-frequency analysis using empirical or variational mode decomposition and the Hilbert-Huang transform.

Apps

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

Functions

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fsstFourier synchrosqueezed transform
ifsstInverse Fourier synchrosqueezed transform
instbwEstimate instantaneous bandwidth
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
dlstftDeep learning short-time Fourier transform
stftLayerShort-time Fourier transform layer
stftmag2sigSignal reconstruction from STFT magnitude
iscolaDetermine whether window-overlap combination is COLA compliant
istftInverse short-time Fourier transform
tfridgeTime-frequency ridges
wvdWigner-Ville distribution and smoothed pseudo Wigner-Ville distribution
xwvdCross Wigner-Ville distribution and cross smoothed pseudo Wigner-Ville distribution
emdEmpirical mode decomposition
vmdVariational mode decomposition
hhtHilbert-Huang transform

Topics

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 and Communications Waveform Classification Using Deep Learning (Phased Array System Toolbox)

This example shows how to classify radar and communications waveforms using the Wigner-Ville distribution (WVD) and a deep convolutional neural network (CNN).

Pedestrian and Bicyclist Classification Using Deep Learning (Radar Toolbox)

Classify pedestrians and bicyclists based on their micro-Doppler characteristics using a deep learning network and time-frequency analysis.

Featured Examples