High resolution linear time-frequency analysis method

Abstract

The invention discloses a high resolution linear time-frequency analysis method. An iteration self-adaption method is adopted to obtain a high resolution instantaneous frequency estimation result, compared with a linear time-frequency analysis method, the time-frequency two-dimensional resolution ratio is substantially improved, and the two-dimensional distinction degree of multiple signals in a time-frequency domain can be remarkably improved; and linear transformation is adopted to perform analysis and processing on the signals, and compared with a nonlinear time-frequency analysis method, influence of cross terms is effectively eliminated, and a time-frequency analysis and processing effect of multiple time-frequency aliasing signals can be further improved. A convergent time-frequency analysis result can be obtained through a few iterations, and has good performance of analyzing and processing linear frequency modulation signals and nonlinear frequency modulation signals, and compared with other improved type time-frequency analysis method, the calculated amount is substantially reduced and the applicability is stronger.

Description

technical field [0001] The invention belongs to the technical field of radio signal processing, in particular to a high-resolution linear time-frequency analysis method. Background technique [0002] Modern wars, especially several local wars in the 1990s show that radio electronic reconnaissance technology has developed from an early auxiliary support role to an important factor involving the entire combat operation. Electronic warfare is an important branch of electronic warfare (EW, Electronic Warfare). The electronic warfare microwave receiver is an important part of the electronic reconnaissance system and intelligence support system. Its main function is to receive non-cooperative signals in complex signal environments. performance directly affects the effect of interference. Its main reconnaissance objects are radar signals and communication signals. In the modern electronic reconnaissance signal environment, the signal form is becoming more and more complex, the nu...

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Problems solved by technology

[0005] In addition to the above two classic time-frequency analysis methods, scholars at home and abroad have also proposed a variety of improved methods. For example, L.B.Almeida introduced the fractional Fourier transform into the field of signal processing, and used its linear transformation properties to eliminate the influence of cross terms. However, this method is only applicable to For the analysis of linear frequency modulation signals, the scope of application is limited; in the article "Analysis of multicomponent LFM signals by a combined Wigner-Houghtransform" published by Barbarossa.S et al. on IEEE Trans. ) to analyze and process the mixed chirp signal, but due to the large amount of calculation of the WHT method, it affects its engineering application value; Qi Lin et al published the article "Multiple points based on fractional Fourier transform" in "Chinese Science" in 2003 In "Detection and Parameter Estimation of Quantitative LFM Signal", a multi-component linear frequency modulation signal analysis technology is proposed based on fractional Fourier transform, and the Newton iteration method is used to reduce the computational complexity; Dai Qionghai et al. in 1997 "Acta Electronics" In the article "Subspace Decomposition of Noisy LFM Signals Based on Randon-STFT Transformation", the STFT and Randon transform were combined to propose a linear frequency modulation signal detection and analysis based on the Randon-STFT transform; but the above two methods are limited For the analysis of linear frequency modulation signals, its processing performance for complex modulation signals needs to be further investigated

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