Weak signal detection method based on joint denoising and frequency modulation

Abstract

The invention discloses a weak signal detection method based on joint denoising and frequency modulation, and belongs to the technical field of signal processing. The method comprises the steps that 1) partial noise suppressing is carried out on low signal to noise ratio signals which are to be detected and are mixed with noise through an autocorrelator; 2) wavelet threshold transforming is carried out on the signals which are processed in the step of 1) and are to be detected, so as to remove residual noise after signal autocorrelation; 3) a modulatable standard signal is used to modulate the frequency of the signals output in the step of 2), so that the modulated signal frequency can meet the detection condition of a dual Duffing oscillator difference system, and high frequency signals in the modulated signals are filtered out through a low pass filter; 4) the signals output by the low pass filter in step of 3) are input into the dual Duffing oscillator difference detection system, and initial state parameters of the system are set; and 5) whether the dual Duffing oscillator difference detection system has the phenomenon of regular intermittence chaos is judged, and if the phenomenon of regular intermittence chaos occurs, a continuous zero method is used to acquire an intermittence chaos period and the frequency of the signals to be detected. Compared with a traditional detection method, the method can be used to detect the weak signals of any frequency in a background with strong noise, and is of great significance in practical application.

Description

technical field [0001] The invention belongs to the technical field of signal processing, and relates to a weak signal detection method based on joint denoising and frequency modulation, in particular to a joint denoising system composed of autocorrelation and wavelet threshold transformation and frequency adjustable standard signal modulation to be tested A method to detect weak periodic signals by using the frequency of the signal. Background technique [0002] Signal detection technology is widely used in the engineering field. If the amplitude of the useful signal is weak relative to the noise, or the amplitude of the useful signal itself is very small, it will be easily overwhelmed by the noise and it will be extremely difficult to detect it. The traditional weak signal detection method is very poor in detecting signals with extremely low signal-to-noise ratio, while the Duffing oscillator chaotic system has the advantages of extreme sensitivity to initial values ​​and ...

AI Technical Summary

Problems solved by technology

Using the autocorrelation method can suppress part of the background noise of the signal to be tested, but the detection signal-to-noise ratio threshold is not ideal

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