Nonlinear signal time-frequency analysis method based on short-time fractional order Fourier transform

A fractional Fourier, nonlinear signal technology, applied in the field of signal time-frequency analysis method, can solve problems such as low time-frequency resolution

Active Publication Date: 2017-10-24
ZHONGBEI UNIV
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Problems solved by technology

Aiming at the problem of low time-frequency resolution of nonlinear signals detected by short-time Fourier transform, the present invention proposes a new time-frequency analysis method for nonlinear signals based on short-time fractional Fourier transform. Time-frequency detection and separation of non-linear signals; especially for the large amount of computing problems that affect the present invention, a search strategy with angle constraints is introduced, which can greatly improve the computing speed; this method can not only improve the single-component nonlinear signal It can also improve the parameter separation and estimation accuracy of multi-component nonlinear signals, and can be applied to the time-frequency analysis of Doppler signals of radar for micro-moving targets.

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  • Nonlinear signal time-frequency analysis method based on short-time fractional order Fourier transform

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Embodiment 1

[0056] Embodiment 1. Nonlinear signal time-frequency analysis method based on short-time fractional Fourier transform

[0057] In this example, the time-frequency analysis method of nonlinear signals based on short-time fractional Fourier transform is given by Figure 1 ~ Figure 3 Jointly shown. The specific implementation steps of the nonlinear signal time-frequency analysis method based on short-time fractional Fourier transform in this example are as follows:

[0058] Step 1, the selection of data signals, the data used in this example is the flapping echo Doppler data of the simulated bird target: assuming that the simulated radar carrier frequency is 10 gigahertz (GHz), the echo signal accumulation time is 10 seconds, and the accumulated The number of pulses is 8192, and the wings and tail of a simulated bird are 1 meter long. The length of the upper arm is 0.5 meter, the length of the forearm is 0.5 meter, and the frequency of flapping the wings is 2 Hz.

[0059] Step ...

Embodiment 2

[0074] Embodiment 2. Nonlinear signal time-frequency analysis method based on short-time fractional Fourier transform

[0075] In this example, the time-frequency analysis method of nonlinear signals based on short-time fractional Fourier transform is given by figure 1 , Figure 4 Jointly shown. The specific implementation steps of the non-linear signal time-frequency analysis method based on short-time fractional Fourier transform of this example are as described in Embodiment 1. The total seven steps, the detection process is also as follows figure 1 A total of 11 processes described in, will not be repeated. The radar system is: the carrier frequency is 3GHz, and the time-frequency characteristics of the transmitted signal are as follows: Figure 4 (a) shown. On the basis of Example 1, this example further verifies the time-frequency analysis of the method of the present invention for a single-component nonlinear signal. The time-frequency analysis method and embodiment...

Embodiment 3

[0076] Embodiment 3. Nonlinear signal time-frequency analysis method based on short-time fractional Fourier transform

[0077] The specific situation of the radar target detection method based on sparse Fourier transform in this example is given by figure 1 , Figure 5 Jointly shown. The specific implementation steps of the non-linear signal time-frequency analysis method based on short-time fractional Fourier transform of this example are as described in Embodiment 1. The total seven steps, the detection process is also as follows figure 1 A total of 11 processes described in, will not be repeated. The radar system is: the carrier frequency is 3GHz, the phase of the transmitted signal is the superposition of two sinusoidal signals, the frequencies of the two sinusoidal signals are 3 Hz and 6 Hz respectively, the sampling frequency of the signal is 100 Hz, and the duration of the signal is 9 seconds, the target signal-to-noise ratio is set to 0 decibels (dB). In this examp...

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Abstract

The invention discloses a nonlinear signal time-frequency analysis method based on short-time fractional order Fourier transform, and the nonlinear signal time-frequency analysis method belongs to the technical field of target signal analysis. The nonlinear signal time-frequency analysis method utilizes short-time fractional order Fourier transform, subjects a signal to segmentation processing and combined processing of different orders of fractional order Fourier transform through short-time fractional order Fourier transform, adopts an angle constraint method for fractional-order order searching, improves the time-frequency resolution of the target signal and the precision of time-frequency analysis, completes the time-frequency analysis of single-component and multi-component nonlinear signals, solves the problems of low time-frequency resolution and difficult separation of the target nonlinear echo signal, is conductive to parameter estimation of the weak target signal, improve the precision of signal parameter estimation, has the advantages of high time-frequency resolution and precise separation of different signals in the time-frequency domain, significantly reduces the amount of computing, provides reliable data support for a follow-up system to complete tasks, and is worthy of adoption and popularization.

Description

technical field [0001] The non-linear signal time-frequency analysis method based on short-time fractional Fourier transform disclosed by the present invention belongs to the technical field of target signal analysis, and specifically relates to a method for single-component and multi-component analysis using short-time fractional Fourier transform. The time-frequency analysis of nonlinear signals solves the problems of low time-frequency resolution and difficult separation of target nonlinear echo signals, improves the estimation accuracy of signal parameters, and provides reliable data support for the completion of subsequent system tasks. Background technique [0002] As we all know, for the detection of nonlinear signals, traditional time-frequency analysis methods mainly include linear time-frequency methods based on short-time Fourier transform and nonlinear time-frequency methods based on Wigner distribution, but these methods have time-frequency resolution The accura...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R23/16
CPCG01R23/16
Inventor 庞存锁侯慧玲韩焱卓辉张秀美
Owner ZHONGBEI UNIV
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