M-File for Computing 3D HHT Time-Frequency Spectrogram
Latest version of MATLAB M-file for calculating three-dimensional Hilbert-Huang Transform time-frequency representations with enhanced functionality
Wigner Transform Analysis of Single-Pulse, LFM, and BPSK Radar Signals
This MATLAB code applies the Wigner transform to three radar signal types—conventional single-pulse, Linear Frequency Modulated (LFM), and Binary Phase Shift Keying (BPSK)—to generate time-frequency distributions. The implementation demonstrates how the Wigner transform reveals distinct time-frequency characteristics for each signal type, enabling comparative analysis of their energy distribution patterns. The code includes signal generation, Wigner computation using quadratic time-frequency representations, and visualization of instantaneous frequency variations.
Synchrosqueezed Wavelet Transform
Daubechies et al. proposed a novel approach combining wavelet transform with reassignment—the synchrosqueezed wavelet transform. This method effectively reorganizes the time-frequency representation obtained from wavelet transform to achieve higher frequency resolution in time-frequency curves. Additionally, it enables decomposition of arbitrary signals into linear combinations of approximately harmonic components. The implementation typically involves MATLAB's cwt function for continuous wavelet transform, followed by frequency reassignment through phase differentiation and spectral squeezing operations.
Principles of Wavelet Time-Frequency (Scale) Plot Generation with Implementation
Principles and Implementation of Wavelet Time-Frequency Plot Generation Through a Practical Example: Using a Synthetic Signal Composed of Two Sine Waves at 100Hz and 200Hz