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Análisis de tiempo-frecuencia

Espectrograma, reasignación, sincrosqueezing, Wigner-Ville, marginales de tiempo-frecuencia, métodos de adaptación de datos

Signal Processing Toolbox™ proporciona funciones y apps que permiten visualizar y comparar el contenido de tiempo-frecuencia de las señales no estacionarias. Calcule la transformada de Fourier de tiempo corto y su inversa. Obtenga estimaciones espectrales nítidas mediante la reasignación o el sincrosqueezing de Fourier. Represente espectrogramas cruzados, distribuciones Wigner-Ville y espectros de persistencia. Extraiga y realice un seguimiento de las crestas de tiempo-frecuencia. Estime la frecuencia instantánea, el ancho de banda instantáneo, la curtosis del espectro y la entropía del espectro. Realice un análisis de tiempo-frecuencia adaptado a los datos mediante la descomposición de modo empírica o variacional y la transformada de Hilbert-Huang.

Apps

Signal Analyzer	Visualizar y comparar múltiples señales y espectros
Signal Labeler	Etiquete atributos de señal, regiones y puntos de interés

Funciones

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Estimadores

`fsst`	Fourier synchrosqueezed transform
`ifsst`	Inverse Fourier synchrosqueezed transform
`instbw`	Estimate instantaneous bandwidth
`instfreq`	Estimate instantaneous frequency
`kurtogram`	Visualize spectral kurtosis
`pkurtosis`	Spectral kurtosis from signal or spectrogram
`pentropy`	Spectral entropy of signal
`pspectrum`	Analyze signals in the frequency and time-frequency domains
`spectrogram`	Spectrogram using short-time Fourier transform
`xspectrogram`	Cross-spectrogram using short-time Fourier transforms
`stft`	Short-time Fourier transform
`dlstft`	Deep learning short-time Fourier transform
`stftLayer`	Short-time Fourier transform layer
`stftmag2sig`	Signal reconstruction from STFT magnitude
`iscola`	Determine whether window-overlap combination is COLA compliant
`istft`	Inverse short-time Fourier transform
`tfridge`	Time-frequency ridges
`wvd`	Wigner-Ville distribution and smoothed pseudo Wigner-Ville distribution
`xwvd`	Cross Wigner-Ville distribution and cross smoothed pseudo Wigner-Ville distribution

Métodos de adaptación de datos

`emd`	Empirical mode decomposition
`vmd`	Variational mode decomposition
`hht`	Hilbert-Huang transform

Temas

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.

Ejemplos destacados

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

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

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Spoken Digit Recognition with Custom Log Spectrogram Layer and Deep Learning

Classify spoken digits using a deep convolutional neural network and a custom spectrogram layer.

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Practical Introduction to Time-Frequency Analysis

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

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Espectrograma cruzado de señales complejas

Resalte las regiones en las que dos señales comparten contenido frecuencial.

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Find Interference Using Persistence Spectrum

Use the persistence spectrum in Signal Analyzer app to detect and analyze brief events.

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Find and Track Ridges Using Reassigned Spectrogram

Use the reassigned spectrogram in Signal Analyzer to sharpen the time and frequency localization of spectrograms.

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