10 results about "Amplitude ratio" patented technology

This invention relates to a method for measuring the stability margin of a constant-temperature hot-wire anemometer based on in-situ open-loop frequency characteristics, belonging to the field of fluid measurement and automatic control technology. The method disclosed in this invention includes the following steps: S1. Connecting an ultra-low frequency low-pass filter to the closed-loop circuit to form an in-situ open-loop system with a DC closed loop and an AC open loop; S2. Injecting a sweep frequency excitation signal E at the bias circuit. stimu And measure the output response E of the amplifier circuit. a By comparing the amplitude ratio and phase difference of the two, the open-loop frequency response G of the system under actual operating conditions of the hot wire is obtained. open (jω); S3. According to G open (jω) Obtain the phase margin of the system and determine its stability. This invention proposes a new method for measuring the stability margin of a constant-temperature hot-wire anemometer, transforming the complex system stability problem into a measurable and analyzable open-loop frequency characteristic stability margin problem, providing a direct and reliable engineering basis for the circuit design of constant-temperature hot-wire anemometers.

The application discloses a three-dimensional positioning method of a seismic source based on a multi-channel amplitude ratio. The method obtains waveform data of the same event on at least four sensor channels and spatial coordinates of the sensors, pre-processes the waveforms, determines an event window corresponding to the event, extracts amplitude indicators of each channel in the event window and performs channel consistency correction, constructs an amplitude logarithm ratio observation on an arbitrary channel based on an exponential decay model to eliminate a source intensity factor, and further forms a constraint related to a distance difference of the seismic source and the sensor. A redundant channel constraint set is further constructed, and an abnormal channel is down-weighted or removed. A weighted nonlinear least square is used in combination with an iterative reweighted least square or a robust loss function to solve the problem, a residual threshold is determined and is updated with iteration. A plurality of candidate solutions are obtained by solving a multi-initial value or a coarse grid initial value in a preset feasible region, and an optimal solution is output. The method reduces the dependence on the arrival time picking, and can be used for microseismic monitoring, acoustic emission positioning and underground engineering safety monitoring.

This application relates to the field of equipment condition monitoring technology, and discloses a method and system for fault diagnosis of the secondary circuit of a current transformer. The method includes: connecting a detection device in series to the secondary circuit to establish a physical circuit; injecting a step-scanning high-frequency excitation signal; synchronously sampling the input power signal and output voltage signal to obtain time-series discrete data; performing a fast Fourier transform on the data to extract the frequency domain complex components; calculating the amplitude ratio and phase difference at different scanning frequencies to generate a joint amplitude-frequency-phase-frequency distribution curve; extracting fusion features from the curve; dividing the dataset after normalization; constructing a basic classifier based on the LightGBM algorithm; introducing the TPE algorithm for hyperparameter global optimization; training a state identification model and outputting fault diagnosis results; and using the SHAP interpretation model to calculate the contribution value of the fusion features and outputting feature distribution information. This invention improves the accuracy and engineering interpretability of secondary circuit fault classification.

The application belongs to the field of piezoelectric driver nonlinear modeling, and particularly discloses a piezoelectric driver creep nonlinear dynamics model and a construction method and system thereof. c (s)=s ‑μ ; wherein s is a Laplace operator; the identification method of the parameter mu includes: constructing input voltage signals with different frequencies omega i , calculating input voltage signal amplitudes U i ; according to the input voltage signals, obtaining output displacement signals of the piezoelectric driver, and simultaneously calculating output displacement signal amplitudes D i ; calculating the amplitude ratio A i of D i and U i ; obtaining a discrete data point set (x i , y i ) which satisfies: according to the linear fitting of the discrete data point set (x i , y i ), determining the slope of the fitted straight line, and determining the parameter mu according to the slope. The model constructed based on the fractional order involves fewer unknown parameters, is easy to identify, and at the same time, the modeling method is not limited by special discrete points in the time / frequency domain, and has higher universality.

This invention relates to a stability measurement method for a constant-temperature hot-wire anemometer based on the identification of equivalent pure delay element parameters, belonging to the field of fluid measurement and automatic control technology. The method disclosed in this invention includes the following steps: S1. Connecting an ultra-low frequency low-pass filter to the closed-loop circuit of the system to form an in-situ open-loop system with a DC closed loop and an AC open loop; S2. Injecting a sweep frequency excitation signal E at the bias circuit. stimu And measure the output response E of the amplifier circuit. a By comparing the amplitude ratio and phase difference of the two, the open-loop frequency response G of the system under actual operating conditions of the hot wire is obtained. open (jω); S3. Using the preset transfer function model G * open (s) Fit the measured frequency response to identify the pure delay element G introduced by non-ideal factors such as circuit distributed parameters and device hysteresis. delay (s), and uses its parameter b to quantify the non-ideal factors of the system. This invention realizes in-situ measurement of system stability, quantifies non-ideal factors into measurable parameters, and provides a reliable basis for system stability analysis and circuit design.

This invention discloses an improved canonical perturbation high-order expansion prediction method and system for the critical flutter wind speed of long, flexible structures. The method includes: Step 1: Acquiring aerodynamic and structural parameters based on the Scanlan self-excited force model; Step 2: Constructing the bending-torsional coupling control matrix equation and introducing small parameters for perturbation expansion; Step 3: Using the improved canonical perturbation method, distinguishing between equal and unequal frequency cases, eliminating long-term terms by constructing eigenvalues, and solving for eigenvalues ​​and modal vectors step by step; Step 4: Deriving explicit analytical solutions for modal frequencies, damping ratios, amplitude ratios, and phase differences; Step 5: Determining the modal frequencies and directly solving for the damping ratio through a single iteration to determine the critical flutter wind speed. This invention decomposes complex nonlinear problems into linear superpositions of components, obtaining explicit closed-form solutions for the parameters. The calculation can be completed in a single iteration, significantly simplifying the analysis process and clearly revealing the influence mechanism of various structural and aerodynamic parameters on flutter instability.

This invention relates to a method for bandwidth evaluation of a constant-temperature hot-wire anemometer based on in-situ open-loop frequency characteristics, belonging to the field of fluid measurement and automatic control technology. The method disclosed in this invention includes the following steps: S1. Connecting an ultra-low frequency low-pass filter to the closed-loop circuit to form an in-situ open-loop system with a DC closed loop and an AC open loop; S2. Injecting a sweep frequency excitation signal E at the bias circuit. stimu And measure the output response E of the hot wire voltage. w By comparing the amplitude ratio and phase difference of the two, the frequency characteristic G is obtained. * gain (jω); S3. Based on the frequency characteristic G * gain The amplitude-frequency response curve of (jω) is used to determine the corner frequency f when its gain drops to -3dB below the DC gain. * c With this transition frequency f * c This invention serves as an estimate of the bandwidth of the constant-temperature hot-wire anemometer. It enables direct measurement and evaluation of the dynamic performance of the constant-temperature hot-wire anemometer in the frequency domain, allowing testing to be completed without changing the bias voltage and DC operating point. This accurately and conveniently reflects the system bandwidth of the hot wire under actual operating conditions.

The application discloses a kind of ultra-high sensitivity MEMS micro-pressure sensor, including pedestal, two resonance beams, two tuning electrodes, two weak coupling beams and four identical pressure films.Tuning electrode is used to adjust the stiffness of resonance beam, to realize the equal inherent frequency of two resonance beams;Two weak coupling beams adopt symmetrical "S" type distribution, improve the micro-pressure measurement sensitivity and quality factor of sensor.By MEMS micro-pressure sensor, using the detection method of segmented amplitude ratio difference can realize the ultra-high sensitivity detection of measured pressure.The ultra-high sensitivity MEMS micro-pressure sensor of the application can be used for micro-pressure measurement in the field of aerospace, has ultra-high sensitivity, and wide detection range, high quality factor, good stability.

This invention discloses a radar target detection method for complex road surfaces, belonging to the field of vehicle-mounted radar technology. The method involves processing the target signal through steps such as intermediate frequency signal sampling, signal FFT operation, spectral leakage suppression, image suppression, and target search. It then filters the original target based on characteristic values ​​such as phase difference and amplitude ratio. This invention enables radar systems to effectively suppress spectral leakage by distinguishing interference signals caused by strong reflectors such as fences, overpasses, and tunnels from the target signal, reducing the number of false targets and the probability of false alarms. This results in higher target detection accuracy, greater reliability, and lower computational load for the radar system, making it applicable to complex road sections such as fences, overpasses, and tunnels.

The present application relates to the field of flow detection, and is a kind of vortex flowmeter anti-transient shock interference method and system based on autocorrelation filtering with single-chip microcomputer (MCU) as core.The method comprises: collecting vortex sensor output signal, segmenting peak-to-peak value and setting mutation threshold, extracting the number of shock in the output signal;Finding the data segment with the least interference after each transient shock interference as the data segment of band-pass filter;Using filter to perform frequency domain autocorrelation filtering on the output signal respectively;Calculating the average amplitude spectrum of the filtered data, extracting the effective peak value, and calculating the amplitude ratio of the effective peak value in the average amplitude spectrum and the amplitude spectrum of the output data before filtering;Extracting the peak frequency corresponding to the maximum ratio in the amplitude ratio as the frequency of vortex flow signal.The method and system proposed by the present application do not depend on empirical parameters, the anti-transient shock interference method based on autocorrelation filtering can be realized in real time with low power consumption, has good anti-interference effect, and is easy to popularize.