Extracting instantaneous frequency (IF) of Micro-Doppler (M-D) is the key to estimating micro-motion parameters. In this paper, firstly, the micro-motion model of coning was set up. Meanwhile, the theoretical analysis and derivation of micro-Doppler were performed. Then we introduced occlusion effect and Time Frequency transform to better accord with the complexity and reality of feature extrac...

In this article, we investigate the debated Instantaneous Frequency (IF) topic. Here, we show that IF is non-unique inherently. We explain how this non-uniqueness can be quantified and explained from a mathematical perspective. The non-uniqueness of the IF can also be observed if different methods of adaptive signal processing are used. We will also show that even if we know the physical origin...

Order tracking (OT) is a signal processing technique that allows capturing the dynamics of the vibration signals measured from rotating machines. In this paper, its propose an OT scheme based on extended Kalman filter (EKF), which comprises the advantages of existing OT techniques. Proposed scheme allows estimation of different spectral/order components of the signal and, in addition, estimates...

Wigner Distribution, one of many methods to compute time frequency representation, satisfies large number of mathematical properties and gives optimal energy concentration in time frequency plane. However, Wigner distribution suffers from severe cross-term interference problem, which limits its scope for practical applications. Different modified versions of Wigner distribution have been develo...

During volitional muscle activation, motor units often fire with varying discharge patterns that include brief, high-frequency bursts of activity. These variations in the activation rate allow the central nervous system to precisely control the forces produced by the muscle. The present study explores how varying the instantaneous frequency of stimulation pulses within a train affects nonisomet...

This study proposes a high-resolution processing technique for seismic data based on the improved synchrosqueezing transform (SST). The SST rearranges complex spectrum of wavelet along frequency axis. However, energy is not concentrated in position with faster change rate. To overcome these problems, proposed method first transformed signal into an analytical one via Hilbert transformation and ...

In this paper, we develop an effective and robust adaptive time-frequency analysis method for signals with intra-wave frequency modulation. To handle this kind of signals effectively, we generalize our data-driven time-frequency analysis by using a shape function to describe the intra-wave frequency modulation. The idea of using a shape function in time-frequency analysis was first proposed by ...

In allusion to harmonic and voltage flicker in microgrid, the local mean decomposition algorithm is adopted to analyze harmonic and voltage flicker in power system. Complex original signals can be decomposed into a number of PF (product function) component, each layer of PF is composed of the envelope signal and frequency modulation function, which contains all the instantaneous amplitude and i...