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Signal instantaneous frequency estimation method based on nonlinear frequency modulation wavelet transformation

A non-linear frequency modulation, instantaneous frequency technology, applied in the field of signal processing

Inactive Publication Date: 2013-04-03
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

So far, through a large number of literature searches, there is no report on the estimation of the instantaneous frequency of a signal using nonlinear frequency modulation wavelet transform technology

Method used

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  • Signal instantaneous frequency estimation method based on nonlinear frequency modulation wavelet transformation
  • Signal instantaneous frequency estimation method based on nonlinear frequency modulation wavelet transformation
  • Signal instantaneous frequency estimation method based on nonlinear frequency modulation wavelet transformation

Examples

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Embodiment 1

[0064] figure 2 In order to simulate the vibration response signal during the start-up process of the Jeffcott rotor, the speed increases exponentially, and the sampling frequency is 500 Hz. When the nonlinear frequency modulation wavelet transform algorithm is used, the length of the Gaussian window is 512, the order of the polynomial kernel function is set to 4th order, and the termination condition is

[0065] ξ ( s ) = mean ( ∫ | IF ( i + 1 ) ( t ) - IF ( i ...

Embodiment 2

[0069] Figure 5 It is a diagram of the experimental device, and the vibration signal is measured by the acceleration sensor. Figure 6 It is the measured vibration signal, and the sampling frequency is 100Hz. When the nonlinear frequency modulation wavelet transform algorithm is used, the length of the Gaussian window is 512, the order of the polynomial kernel function is set to 7th order, and the threshold δ is set to 0.1%. Before the judgment condition reaches the threshold, a total of 3 non-linear frequency modulation wavelet transform operations are performed; Figure 7 and Figure 8 Respectively represent the time-frequency distribution results of the first and third transformations, the extracted time-frequency distribution maximum value curve and the estimated rotational speed curve. Obviously, Figure 8 The time-frequency aggregation ratio of Figure 7 The results of short and medium time Fourier transform are much better. The transient speed of the rotor during...

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Abstract

The invention discloses a method for estimating the instantaneous frequency of a non-stationary signal and is applied to the field of signal processing. The method utilizes the nonlinear frequency modulation wavelet transformation technology, takes into consideration of influences of polynomial kernel characteristic parameters on time-frequency analysis performance during nonlinear frequency modulation wavelet transformation, and selects proper kernel characteristic parameters so as to realize precise estimation on instantaneous frequency of a non-stationary signal. The method has the advantages as follows: 1, due to adoption of the nonlinear frequency modulation wavelet transformation technology, the purpose of precise estimation on the instantaneous frequency of the non-stationary signal can be achieved, and the adopted key technology is selection of nonlinear polynomial kernel characteristic parameters of nonlinear frequency modulation wavelet transformation; 2, by using the instantaneous frequency estimation technology based on nonlinear frequency modulation wavelet transformation, the defect of complicated and overloaded computation of a conventional technology can be avoided, and the method has the advantages of simplicity and high precision; and 3, the method is simple and feasible in computation, and can be applied to the technical field of signal processing and the like.

Description

technical field [0001] The invention relates to the field of signal processing, in particular to a method for estimating the instantaneous frequency of a non-stationary signal, in particular to a method for estimating the instantaneous frequency based on nonlinear FM wavelet transform. Background technique [0002] In practical engineering applications, non-stationary signals are ubiquitous, such as voice, biomedical, radar, sonar and seismic monitoring signals and various mechanical vibrations, etc., and their common feature is that there is a changing frequency, that is, its statistical characteristics ( correlation function, power spectrum, etc.) are time-varying functions. The traditional Fourier transform (FT) is aimed at periodic stationary signals, it depends on the global information of the signal, and cannot reflect the local characteristics of the signal, so it is not effective for analyzing non-stationary signals. The instantaneous frequency IF (Instantaneous Fre...

Claims

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Application Information

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IPC IPC(8): G06F19/00
Inventor 彭志科
Owner SHANGHAI JIAO TONG UNIV
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