Harmonic wavelet frequency domain extraction and vibration source identification method for weak vibration signal

A technology of harmonic wavelet and weak vibration, which is used in the measurement of ultrasonic/sonic/infrasonic waves, measuring devices, instruments, etc. Independence, etc. are not satisfied

Inactive Publication Date: 2010-06-09
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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Problems solved by technology

Although these three functions are used in domestic literature, the dependence of the partial coherence function on the prioritization of signal sources is rarely mentioned
As for the virtual coherence function, although domestic literature uses a

Method used

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  • Harmonic wavelet frequency domain extraction and vibration source identification method for weak vibration signal
  • Harmonic wavelet frequency domain extraction and vibration source identification method for weak vibration signal
  • Harmonic wavelet frequency domain extraction and vibration source identification method for weak vibration signal

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Embodiment Construction

[0036] The implementation of the invention will be further described below in conjunction with the accompanying drawings. figure 1 It is a flow chart of the method of the present invention, such as figure 1 As shown, the method includes the following four steps.

[0037] Step 1: Decompose the signal using harmonic wavelet transform.

[0038] Depend on

[0039]

[0040]

[0041] The real function Ψ of the Haar wavelet function determined by the inverse Fourier transform of e and Ψ o (Subscripts e and o indicate that the real number is an even function and an odd function of the variable x respectively) can be combined into a complex function

[0042] Ψ(x)=Ψ e(x)+iΨ o (x) (2)

[0043] Its frequency-domain waveform has excellent tight support and box-shaped characteristics. From this, the complex function can be defined

[0044] Ψ(x)=(e i4πx -e i2πx ) / i2πx (3)

[0045] is a harmonic wavelet. Use (2 j x-k) instead of x in formula (4) (where j and k are both int...

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Abstract

The invention discloses a harmonic wavelet frequency domain extraction and vibration source identification method for a weak vibration signal. The method adopts harmonic wavelet transformation to realize frequency domain extraction and time domain reconstruction on the weak vibration signal, and realizes frequency domain extraction of a weak periodic vibration signal in the strong noise background. The invention also provides a vibration signal source identification method based on the coherence function analysis. The vibration signal source identification method comprises the following steps of: firstly judging the independent number of signal sources on the whole frequency band, then detecting whether important signals are missed or not, and finally respectively identifying the independent and non-independent conditions; for the non-independent signal sources, providing a filter method for carrying out priority ordering; and after carrying out priority ordering, detecting whether the important signal sources are missed or not by using a multiple coherence function, and then respectively identifying the independent signal sources and the non-independent signal sources by using a coherence function and a partial coherence function. By adopting the scheme, the weak vibration signal can be accurately detected, and the vibration sources can be effectively identified.

Description

technical field [0001] The invention relates to a detection method and a signal processing technology, and belongs to a weak vibration signal detection method, including wavelet frequency domain extraction of the signal and coherent function vibration source identification. Background technique [0002] The signal is weaker than the noise, and the signal that cannot be extracted by traditional detection methods is called a weak signal. Weak signal detection refers to extracting useful signals from noise to achieve the purpose of measuring signals weaker than noise. Weak signal detection technology uses the methods of electronics, information theory, computer and physics to analyze the causes and laws of noise generation, study the characteristics and correlation of the measured signal, and detect weak useful signals submerged by noise. The scope of application covers the fields of electricity, mechanical vibration, fault diagnosis, mechanics, materials and so on. The objec...

Claims

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Application Information

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IPC IPC(8): G01H17/00
Inventor 李舜酩辛江慧陈茉莉
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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