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.

Functions

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
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

Apps

Signal AnalyzerVisualize and compare multiple signals and spectra

Topics

Time-Frequency Gallery

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

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.

Featured Examples

Classify ECG Signals Using Long Short-Term Memory Networks

Classify ECG Signals Using Long Short-Term Memory Networks

Classify heartbeat electrocardiogram data using deep learning and signal processing.

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Waveform Segmentation Using Deep Learning

Waveform Segmentation Using Deep Learning

Segment human electrocardiogram signals using time-frequency analysis and deep learning.

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Radar Waveform Classification Using Deep Learning

Radar Waveform Classification Using Deep Learning

Classify synthetic radar waveform types using the Wigner-Ville distribution and a deep convolutional neural network.

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Pedestrian and Bicyclist Classification Using Deep Learning

Pedestrian and Bicyclist Classification Using Deep Learning

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

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Practical Introduction to Time-Frequency Analysis

Practical Introduction to Time-Frequency Analysis

Perform and interpret basic time-frequency signal analysis of nonstationary signals.

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Cross-Spectrogram of Complex Signals

Cross-Spectrogram of Complex Signals

Highlight the regions where two signals share frequency content.

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Find Interference Using Persistence Spectrum

Find Interference Using Persistence Spectrum

Visualize an interference narrowband signal embedded within a broadband signal.

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Find and Track Ridges Using Reassigned Spectrogram

Find and Track Ridges Using Reassigned Spectrogram

Track ridges of an echolocation pulse emitted by a bat.

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Signal Processing Toolbox Documentation
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