Multiple-stable-state stochastic resonance weak signal detection method based on wavelet and parameter compensation

The invention discloses a multiple-stable-state stochastic resonance weak signal detection method based on wavelet and parameter compensation. The method comprises the following steps: implementing parameter compensation on a noise-containing weak signal, and multiplying a signal parameter, a noise parameter and system parameters by a compensation parameter to counteract the influence of a damping term so as to detect a high-frequency weak signal; implementing multiscale wavelet discrete transformation on the compensated signal to obtain multiple signals at different scale frequencies, adjusting the amplitude of the signal at each scale, and implementing reconstruction; implementing multiple-stable-state stochastic resonance treatment on the reconstructed signal so that each frequency section of a to-be-detected signal is enhanced, implementing band-pass filtering resynthesis on the output of each frequency section to obtain an enhanced multi-frequency weak signal, implementing envelope ...

Rotary machinery fault diagnosis method based on fractional order stochastic resonance

The invention discloses a rotating machine fault diagnosis method based on fractional order stochastic resonance, and belongs to the technical field of mechanical fault diagnosis, and the method comprises the steps: calculating the k-nearest neighbor distance and k-nearest neighbor density through extracting the multi-dimensional features of each data segment of a signal, constructing a rise density abnormal factor, and calculating the k-nearest neighbor distance and k-nearest neighbor density of the signal; abnormal data segments are screened and eliminated according to a 3 sigma criterion, and vibration signals of which large impact noise is preliminarily removed are obtained; the Caputo-Fabrizio fractional derivative is introduced into a second-order classical bistable stochastic resonance model, so that the amplification capability of the system on weak characteristics is effectively improved; and inputting the preprocessed signal into the model, extracting fault characteristics through ...

Method for detecting weak signal on basis of parameter compensation multistable random resonance system

The invention discloses a method for detecting a weak signal on the basis of a parameter compensation multistable random resonance system. The method comprises the following steps of (1) performing parameter compensation on a noise-containing weak signal, i.e. adding an amplifying link in a multistable Langevin equation, to offset the trend that an amplitude value is smaller after the signal passes through a multistable system, so that the method can be used for detecting a high-frequency weak signal; (2) inputting the compensated signal into the multistable system, wherein the multistable system is higher than a bistable system in detectability and can be used for detecting the weak signal with lower signal to noise ratio; (3) performing envelope demodulation analysis on the output signal of the multistable system, and analyzing an envelope diagram to extract the characteristics of the weak signal, so that detection on the weak signal is finished. By the method, the weak signal can be ...

Method for detecting closely spaced frequency components of non-stationary signals

The invention discloses a method for detecting closely spaced frequency components of non-stationary signals. The method comprises the following steps: performing EMD on non-stationary signals to be detected, and then obtaining the frequency spectrum and limit spectrum of the non-stationary signals to be detected through Hilbert transformation; obtaining the value of each frequency component through processing frequency spectrum graph data, and extracting signals with different frequency components by use of a filtering method; determining whether each frequency component comprises multiple frequency values which are not separated through AMD; if a frequency aliasing phenomenon occurs in the signals, performing the AMD on the frequency components, and separating signals with similar frequencies; and then performing operation on the separated signals according to a previous step sequence until single-frequency signals are separated, such that it can be ensured that the decomposed signals ...

Weak signal detection method based on double-coupling Duffing vibrators and scale varying

The invention discloses a weak signal detection method based on double-coupling Duffing vibrators and scale varying. The weak signal detection method comprises the following steps of (1) constructing a double-coupling Duffing vibrator weak signal detection system equation, analyzing various states of a system and confirming a critical chaos state parameter; (2) establishing a double-coupling Duffing vibrator array detecting model and setting an equation parameter; (3) analyzing frequency spectra of signals to be detected to obtain an estimated value of frequency of the signals to be detected; (4) varying the scale of the signals to be detected so as to ensure that the signals are in a detection range of a vibrator array; and (5) inputting the signals to be detected in the double-coupling Duffing vibrator array after the scale of the signals is varied and calculating accurate frequency configuration of the signals to be detected. Weak periodic signals can be detected on the basis of the ...

Method for removing mode mixing in empirical mode decomposition (EMD) based on AMD (Analytical Mode Decomposition)

The invention discloses a method for removing mode mixing in empirical mode decomposition (EMD) based on AMD (Analytical Mode Decomposition). The method comprises the following steps: (1) EMD on original signals is carried out so as to obtain each intrinsic mode function (IMF), and whether each IMF is subjected to a mode mixing phenomenon or not is observed; (2) the instantaneous frequency characteristic of a first intrinsic mode function (IMF1) is solved, and whether the mode mixing phenomenon exists or not can be judged according to the instantaneous frequency characteristic; (3) if the instantaneous frequency of the IMF1 has frequency components with relatively large difference, the condition that the mode mixing phenomenon occurs is indicated, and the start-stop time of discontinuous signals can be obtained according to the instantaneous frequency; (4) if the mode mixing phenomenon exists, a binary frequency value is determined according to the frequency components in the instantaneous ...

CO-OFDM (COherent light-Orthogonal Frequency Division Multiplexing) system channel estimation method based on channel impulse response filtering

The invention provides a CO-OFDM (COherent light-Orthogonal Frequency Division Multiplexing) system channel estimation method based on channel impulse response filtering, which can improve the noise resistance capability for channel estimation with smaller system expenditure. The method comprises the following steps of: carrying out IFFT (Inverse Fast Fourier Transform) transform on a channel transfer function estimated by an LS (Least Square) channel to obtain a channel impulse response; calculating the length of the channel impulse response according to optical fiber channel parameters, such as dispersion, polarization mode dispersion and the like; constructing a Blackman window function according to the length of the channel impulse response; carrying out time domain multiplication on the channel impulse response and the Blackman window function; carrying out FFT transform on the processed channel impulse response to obtain a channel transfer function of which the noise is filtered out ...

Rotary mechanical fault diagnosis method based on analytical modal decomposition

The invention relates to a rotary mechanical fault diagnosis method based on analytical modal decomposition. The rotary mechanical fault diagnosis method comprises the following steps: (1) if the fault character frequencies possibly existing in a certain rotary machine are f1, f2, f3, ..., fn, carrying out the analytical modal decomposition on original vibration signals, and extracting the signals of frequency bands of the fault character frequencies; (2) determining the frequency spectrums of all the extracted signals to determine whether the components of the fault character frequencies exist in the frequency spectrums; (3) maintaining the signal frequency spectrums with the fault character frequencies, and removing the frequency spectrums without the fault character frequencies; (4) setting the fault character frequencies contained in the signals extracted through the analytical modal decomposition method to be f1, f2, f3, ..., fm, and judging whether faults and parts with failure exist ...

一种用于高速制造双向拉伸聚丙烯薄膜专用树脂

A special resin used for quickly preparing the bidirectional stretching polypropylene film contains homopolymerized polypropylene resin, halogen absorbent and the antioxidizing agent which is the composition of tetra [beta-(3,5-dibert-butyl-4-hydroxyphenyl) propionate] pentacrythritol ester, tri (2,4-di-tert-butyl phenyl) phosphite, and 1,3,5-tri (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate. Its advantage is high resistance to thermal oxidization and degradation.

Chines medicine for treating vitiligo and preparation method thereof

The present invention discloses a Chinese medicine for curing vitiligo and its preparation method. Its prescription comprises ledebouriella root, Chineses angelica root, ligusticum root, flowery knotweed root, biota seed, carthamus flower, astragalus root, ovate atractylodes root, salvia root, psoralea seed ,dahurian angelica root, tribulus fruit, dodder seed, prepared rehmannia root ,sping jujube kernel, corydalis tuber, akebia fruit and codonopsis root. Its preparation method includes the following steps: using prepared flowery knotweed root; stir-frying Chinese angelica root and ligusticumroot with wine; stir-frying prepared rehmannia root, psoralea seed, dodder seed, codonopsis and ovate atractylodes root; cooking tribulus fruit; stir-frying salvia root with pig blood; mix-frying astragalus root with honey; light stir-frying spiny jujube kernel and frosting biota seed. Said Chinese medicine has no abnormal side effect ,and its total effective rate is up to 95%, curative rate is...

Chinese medicine for treating vitiligo and preparation method thereof

Integrated buckling guide fastener for threaded casing head and installation method for casing head

The invention provides an integrated buckling guide fastener for a threaded casing head. The fastener comprises a pallet joint, a fastening flange, a buckling guide flange and a thrust rolling-ball rolling-needle bearing; the shaft of the pallet joint is sequentially sleeved with the fastening flange, the buckling guide flange and the thrust rolling-ball rolling-needle bearing from top to bottom, the lower end of the buckling guide flange is fixedly connected with the thrust rolling-ball rolling-needle bearing, the fastening flange and the thrust rolling-ball rolling-needle bearing are both fixedly arranged on the shaft of the pallet joint, and the diameter of a support head at the lower end of the pallet joint is smaller than the inner diameter of the casing head. According to the integrated buckling guide fastener for the threaded casing head, buckling guide can be conducted easily to achieve connection and fastening of the whole casing head after free rotation and buckling, the problems ...