Instantaneous frequency extraction method of Doppler signals

A technology of Doppler signal and instantaneous frequency, which is applied in the field of signal processing, can solve the problems of long calculation time and low measurement accuracy of instantaneous frequency of objects, and achieve the effect of real-time measurement, high precision and large measurement range

Inactive Publication Date: 2016-10-26
盛思(河南)仪器科技有限公司
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Problems solved by technology

[0005] The present invention provides a method for extracting the instantaneous frequency of the Doppler signal, aiming at the existing problems of low measurement accuracy and long calculation time for the instantaneous frequency of the object.

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  • Instantaneous frequency extraction method of Doppler signals
  • Instantaneous frequency extraction method of Doppler signals
  • Instantaneous frequency extraction method of Doppler signals

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Embodiment Construction

[0028] The present invention will be further described in detail below in conjunction with accompanying drawings and examples.

[0029] First of all, in the field of laser Doppler velocimetry, the interferometric method is usually used for velocity measurement, so the output signal of the interferometer is composed of signal light and reference light.

[0030] The light intensities of signal light and reference light can be expressed as and A 1 、A 2 are the amplitudes of signal light and reference light respectively, ω 1 , ω 2 are the frequencies of signal light and reference light, respectively, are the phases of the signal light and the reference light, respectively, and t is the time parameter.

[0031] The output signal V of the interferometer can be expressed as follows:

[0032]

[0033] Among them, η represents the conversion efficiency of the photodetector, I represents the light intensity of the interference superposition signal, and Φ(t) is the phase of ...

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Abstract

The present invention relates to an instantaneous frequency extraction method of Doppler signals, and belongs to the signal processing technology field. According to the present invention, for the Doppler signals outputted by various interference velocimeters, firstly the appropriate parameters, such as the wavelet, the threshold type, the decomposition layer number, the vanishing moment, etc., are selected to carry out the wavelet de-noising on the output signals to smooth the edges; after then the amplitude modulation-frequency modulation decomposition is carried out on the de-noised signals in an iteration manner, and the envelopes of the signals are extracted and are normalized; and finally, the instantaneous frequencies of the normalized signals are extracted by a direct orthogonal method, and an estimation curve of the instantaneous frequencies is obtained in a least-square fitting manner. According to the present invention, firstly the signals are de-noised, so that the direct orthogonal method which is more sensitive to the noise originally can be applied to the Doppler signals, and the simulation results show that on the condition of selecting the appropriate parameters, an error of an instantaneous frequency value obtained by the present invention and a theoretical value is less than 0.5%, the calculation time and the sampling point number are positively related, and the calculation velocity is faster.

Description

technical field [0001] The invention relates to a method for extracting the instantaneous frequency of Doppler signals, in particular to extracting the instantaneous frequency of output signals of various laser velocity interferometers, and belongs to the technical field of signal processing. Background technique [0002] Laser Doppler velocimetry has been widely used in many fields such as medicine, metrology, and chemistry since laser was first proved to be applicable to flow velocity measurement. Although the current laser Doppler velocity measurement technology is very mature in fluid velocity measurement and can achieve high accuracy, there are still some problems in measuring the velocity of solids, especially solids with large acceleration. The reason is that the reflection of solids is more complicated than that of fluids, and most of the output signals are non-stationary signals, and the signal processing is more difficult. [0003] For most Doppler velocimeters, s...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S7/493G01S17/58G01P5/26
CPCG01P5/26G01S7/493G01S17/58
Inventor 王国华许思晨聂晶
Owner 盛思(河南)仪器科技有限公司
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