ANALYSIS OF TIME-FREQUENCY TRANSFORMATIONS OF NON-STATIONARY QUASIPERIODIC BIOMEDICAL SIGNALS

2020 ◽  
Author(s):  
Maksim Alehin ◽  
Aleksey Bogomolov
Keyword(s):  
Biomedical Signals ◽  
Time Frequency ◽  
Advantages And Disadvantages ◽  
Periodic Signals ◽  
Frequency Transformations

The results of the analysis of time-frequency transformations based on the systematization of their main characteristics in the tasks of processing and analyzing patterns of non-stationary quasi-periodic signals are presented, the advantages and disadvantages of using each of the transformations are specified

scholarly journals Oscillatory Biomedical Signals: Frontiers in Mathematical Models and Statistical Analysis

2021 ◽  
Vol 7 ◽  
Author(s):  
Hau-Tieng Wu ◽  
Tze Leung Lai ◽  
Gabriel G. Haddad ◽  
Alysson Muotri
Keyword(s):  
Statistical Analysis ◽  
Empirical Bayes ◽  
Network Formation ◽  
Markov Models ◽  
Hidden Markov ◽  
Biomedical Signals ◽  
Time Frequency ◽  
Bayes Inference ◽  
Cardiorespiratory Patterns ◽  
Parameter Estimators

Herein we describe new frontiers in mathematical modeling and statistical analysis of oscillatory biomedical signals, motivated by our recent studies of network formation in the human brain during the early stages of life and studies forty years ago on cardiorespiratory patterns during sleep in infants and animal models. The frontiers involve new nonlinear-type time–frequency analysis of signals with multiple oscillatory components, and efficient particle filters for joint state and parameter estimators together with uncertainty quantification in hidden Markov models and empirical Bayes inference.

Overview of Time-Frequency Analysis Techniques in Vibration Signals of Rotating Machinery

2014 ◽  
Vol 684 ◽  
pp. 124-130
Author(s):  
Hong Li ◽  
Qing He ◽  
Zhao Zhang
Keyword(s):  
Frequency Analysis ◽  
Local Characteristic ◽  
Vibration Signals ◽  
Time Frequency Analysis ◽  
Hilbert Huang Transform ◽  
Time Frequency ◽  
Analysis Techniques ◽  
Advantages And Disadvantages ◽  
Analysis Methods ◽  
Short Time

There is very rich fault information in vibration signals of rotating machineries. The real vibration signals are nonlinear, non-stationary and time-varying signals mixed with many other factors. It is very useful for fault diagnosis to extract fault features by using time-frequency analysis techniques. Recent researches of time-frequency analysis methods including Short Time Fourier Transform, Wavelet Transform, Wigner-Ville Distribution, Hilbert-Huang Transform, Local Mean Decomposition, and Local Characteristic-scale Decomposition are introduced. The theories, properties, physical significance and applications, advantages and disadvantages of these methods are analyzed and compared. It is pointed that algorithms improvement and combined applications of time-frequency analysis methods should be researched in the future.

scholarly journals APPLICATION OF ISO-FREQUENCY MAPS TO TIME-LAPSE DATA

2017 ◽  
Vol 35 (3) ◽  
Author(s):  
Wagner Moreira Lupinacci ◽  
Anderson Peixoto de Franco ◽  
Fernando Vizeu Santos ◽  
Marco Antonio Cetale Santos
Keyword(s):  
Wavelet Transform ◽  
Energy Density ◽  
Curvelet Transform ◽  
Time Lapse ◽  
Morlet Wavelet ◽  
Seismic Exploration ◽  
Time Frequency ◽  
Advantages And Disadvantages ◽  
Morlet Wavelet Transform ◽  
Non Stationary Signal

ABSTRACT. Time-frequency transforms are widely used in seismic exploration. These transforms enable analysis of the energy density of a non-stationary signal as functions of amplitude, time and frequency. The representation of energy density is not unique, and each transform has its advantages and disadvantages. The choice of which transform should be used depends on the application. In this paper, we propose a new way to analyze time-lapse anomalies using iso-frequency panels obtained by time-frequency transforms. We compared the iso-frequency panels of the Morlet Wavelet Transform and Choi-Williams Distribution. These panels revealed different characteristics and can provide additional information for the interpretation of time-lapse anomalies. We used seismic data from the Marimbá field of the Campos Basin, Brazil, for which base and monitor acquisitions were held in 1984 and 1999, respectively. We also used a special filtering approach to enhance seismic resolution and remove noise, whereby we applied the curvelet transform to remove noise, and employed a tool to correct the residual moveout and inverse Q filtering for attenuation correction. Then we analysed the time-lapse anomalies using iso-frequency panels. The main time-lapse anomalies appeared in the form of clouds in the iso-frequency panels obtained by the Morlet Wavelet Transform approach. Iso-frequency panels obtained by Choi-Williams Distribution showed a higher sensitivity and resolution for analyzing the anomalies. Our results show the great potential of these transforms for visualization of time-lapse anomalies. Keywords: time-lapse anomalies, spectrogram, Morlet Wavelet Transform, Choi-Williams Distribution. RESUMO. Transformadas tempo-frequência são amplamente utilizadas na exploração sísmica. Estas transformadas permitem a análise da densidade de energia de um sinal não-estacionário como funções de amplitude, tempo e frequência. A representação da densidade de energia de um sinal não é única, e cada transformada tem suas vantagens e desvantagens. A escolha da transformada que deve ser usada depende da aplicação. Neste artigo, propomos uma nova abordagem para analisar anomalias de dados time-lapse usando painéis iso-frequência obtidos através de transformadas tempo-frequência. Comparamos os painéis iso-frequência obtidos com a Transformada Wavelet de Morlet e a Distribuição de Choi-Williams. Estes painéis revelaram diferentes características que podem fornecer informações adicionais para a interpretação de anomalias time-lapse. Os dados sísmicos utilizados foram do Campo de Marimbá da Bacia de Campos, Brasil, os quais as aquisições base e monitor foram realizadas em 1984 e 1999, respectivamente. Antes da análise dos painéis iso-frequência, usamos um workflow para melhorar a resolução sísmica e a razão sinal-ruído. Neste workflow, aplicamos a Transformada Curvelet para remover ruídos aleatórios e coerentes, uma ferramenta para corrigir o moveout residual e um Q-filter para correção dos efeitos da atenuação. Após este workflow, as principais anomalias time-lapse apareceram na forma de nuvens nos painéis iso-frequência da Transformada Wavelet de Morlet. Já os painéis iso-frequência da Distribuição de Choi-Williams apresentaram uma maior sensibilidade e resolução para análise dessas anomalias. Os resultados mostraram o grande potencial dessas transformadas para a visualização e interpretação de anomalias time-lapse. Palavras-chave: anomalias time-lapse, espectrograma, Transformada Wavelet de Morlet, Distribuição Choi-Williams. 

Comparative characteristics of anti-collision processing of radio signal from identification tags on surface acoustic waves

2019 ◽  
pp. 48-56 ◽  
Author(s):  
A. V. Sorokin ◽  
A. P. Shepeta ◽  
V. A. Nenashev ◽  
G. M. Wattimena
Keyword(s):  
Signal Processing ◽  
Surface Acoustic Waves ◽  
Group Identification ◽  
Sensor Data ◽  
Correct Identification ◽  
Processing Methods ◽  
Time Frequency ◽  
Advantages And Disadvantages ◽  
Identification Tags ◽  
Signal Processing Methods

Introduction:Collision of information signals is a common problem in the measurement of physical magnitudes, such as temperature, pressure, stress, etc., with acoustic-electronic sensors. This problem is caused by overlapping response signals in the time domain, which makes it difficult to interpret correctly the device identification codes or the sensor data received.Purpose:Analysis of anticollision algorithms for radio-frequency tag code detection and identification by response information signals from acoustic-electronic devices which use the methods of time, frequency and frequency-time division of the response radio signals.Methods:Probabilistic methods for calculating the parameters of digital detectors of radio pulse bursts with given false alarm values and gaussian white noise background; individual code group identification methods when studying the attenuation of acoustic-electric signal during their propagation in the tag substrate, taking into account the dependence of the attenuation on the tag topology.Results:We have derived analytical expressions to calculate the probability of the correct identification of each tag, taking into account the dependence on tag topology, attenuation characteristics, the anti-collision signal processing methods and the signal-to-noise ratios. Curves which allow you to compare the advantages and disadvantages of the considered anti-collision signal processing methods are calculated and shown in the article. The analysis of the graphic charts demonstrating the correct identification probability has shown that identification tags with frequency-time coding have better ratios as compared to frequency or time methods of collision prevention.Practical relevance:The obtained result allows you to effectively evaluate the condition of technical objects, improving the predictability and prevention of possible environmental and man-made disasters.

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