451 results about "Frequency curve" patented technology

In order to characterize the optical characteristics of a device, a source of light having a variable frequency with a polarization state which varies linearly with frequency is provided as an input to the device under test. The input light is also passed through a known reference path and is added to the light output from the device under test in a beam combiner. The combined light for the frequencies of interest is split into two orthogonal polarizations which are then detected in a spectral acquisition apparatus and supplied to a microprocessor. The spectral measurements are digitized and curve-fitted to provide optical power versus optical frequency curves. Fourier transforms of each of the curves are calculated by the microprocessor. From the Fourier transforms, the four arrays of constants are calculated for the Jones matrix characterizing the device under test.

A system, apparatus, and method for determining the distance between two objects using an indirect propagation delay measurement is disclosed. A frequency hopping scheme (such as the Bluetooth™ technology) is used to measure the relative phase offset of the received signal between the various frequencies. For a given distance between the objects, the phase offset vs. frequency curve is a straight line with the slope dependent upon the measured distance. After the phase of the received signals is detected, the data is plotted on a curve and the slope is calculated.

The invention relates to system and method for detecting the transformer winding state by using constant-current sweep frequency power source excitation. A measurement and control analysis module controls sweep frequency power source and applies output constant-current sweep frequency excitation signals by an exciting transformer at a high-voltage side of the transformer to be detected; a vibration sensor measures vibration response signals of a transformer winding to be detected at different excitation frequencies; a vibration signal collector collects and preprocesses the signals measured by the vibration sensor; and the measurement and control analysis nodule carries out spectrum analysis to the received and processed vibration response signal data, displays and records a resonant frequency curve of the transformer winding on a frequency domain, compares with the resonant frequency curve previously measured and recorded as well as the vibration frequency curve of a transformer three-phase coil, and judges the state of the transformer winding to obtain the measuring result. The invention can effectively and sensitively detect the states of looseness or deformation of the transformer winding for prompt repair or replacement so as to avoid a fault of abrupt short circuit of the transformer caused by damage of the winding structure.

The invention discloses a method for quantitatively recognizing an oil deposit dominant flow channel adopting a zero dimension comparison plate. The method includes the following steps: firstly collecting geological parameters and fluid parameters of an oil field to draw a parameter distribution cumulative frequency curve and obtain corresponding distribution intervals and distribution characteristics; according to the parameter distribution characteristics of a target oil deposit, calculating a water drive development dynamic through the combination with corresponding figure conceptual models; finding out the water absorption parameters and liquid production parameters of layers with the maximum and minimum water absorption capability and liquid production capability for zero dimension treatment through the statistics of conceptual model results; drawing a zero dimension parameter distribution plate, and dividing a dominant channel developing space through the cluster analysis method and obtaining a quantitative plate; and performing the single-well zero dimension parameter treatment, and judging the developing condition of the dominant flow channel through the zero dimension comparison plate. According to the invention, the analysis data source is wide, the cost is low, the spend time is short, personnel at an ore yard can use the method conveniently, the individual judgment on each injection and production well in the oil deposit is realized, the quantitative judging standard is given, and the specific developing layer of the dominant flow channel can be confirmed.

The invention discloses a precession target micro-Doppler extracting method based on instant frequency modulation rate estimation. The precession target micro-Doppler extracting method based on instant frequency modulation rate estimation comprises the steps that (1) an equivalent scattering point model of a spatial precession conical target is established, echo signals of the conical target are received by a radar, echo sequences are obtained from the echo signals by using the equivalent scattering point model; (2) frequency modulation rates of the echo sequences are estimated with a relaxation demodulation line frequency modulation method; (3) the frequency modulation rates of the echo sequences are processed through a random sampling consistency algorithm, and P frequency modulation rate curves are obtained; (4) integral operation is carried out on the P frequency modulation rate curves respectively, and P instant micro-Doppler frequency estimation curves are obtained. According to the precession target micro-Doppler extracting method based on instant frequency modulation, high estimation accuracy can be obtained under the situation of the lower signal to noise ratio. The precession target micro-Doppler extracting method based on instant frequency modulation can be applied to analysis of the micro-Doppler frequency of the spatial precession conical target.

The invention belongs to the field of flood control safety design of reservoirs, and relates to a method of determining downstream design flood of cascade reservoirs. The method comprises the following steps that by the adoption of the Copula function, multi-dimensional simultaneous distribution of the section flood volume and the regional flood volume of the reservoirs is constructed, the explicit expression of a conditional probability function is deduced, the frequency curve of the conditional probability is dispersed, and according to the principle of probability combination discrete summation, the design value and the corresponding probability of the annular maximum peak discharge of downstream sections are determined after flood regulation is conducted through the cascade reservoirs. The method can overcome the defects of traditional determination technologies of the design flood of the cascade reservoirs, and provides more comprehensive reference information for cascade planning and development of drainage basins.

The invention discloses a synchronous compression transformation order analysis method for rolling bearing fault diagnosis. According to the method, firstly, SST is utilized to analyze a variable-speed vibration signal of a bearing to obtain time-frequency distribution of the vibration signal; secondly, an instantaneous frequency ridge of frequency conversion is extracted and subjected to high-order polynomial fitting, a fitted instantaneous frequency curve is obtained, and phase discrimination time marks are solved according to the fitted instantaneous frequency curve; thirdly, equal-angle resampling is performed on the original vibration signal to obtain an angular domain signal; and fourthly, Hilbert envelope demodulation is performed on the angular domain signal, an envelope order spectrum of the angular domain signal is solved, whether the rolling bearing has a fault or not and the fault type are judged by analyzing the envelope order spectrum, a diagnosis result is given, maintenance suggestions are proposed, and therefore normal running of a metro vehicle is guaranteed. Through the synchronous compression transformation order analysis method, instantaneous frequency conversion information contained in the vibration signal can be precisely extracted, order tracking is realized, a specific hardware device is not needed, the installing process is greatly simplified, and thefault monitoring cost is lowered.

The disclosed device includes core control module, excitation module and data acquisition and control module. The data acquisition and control module includes vibration sensor, charge amplifier and data acquisition unit connected to each other through circuits. The excitation module includes constant current source in frequency conversion and excitation transformer. Through analyzing change of natural resonance frequency curve of transformer winding, the disclosed device detects loosening status of winding, providing very high detection sensitivity.

The invention discloses a security monitoring method based on an air conditioner. The security monitoring method comprises the steps of: using an image collection device on the air conditioner to monitor that whether moving people exists in a room; when monitoring that the moving people exists in the room, collecting indoor images according to a preset frequency curve; extracting facial features in the collected images to obtain the facial features corresponding to the collected images, and matching the obtained facial features with preset facial features; and when the obtained facial features are failed to be matched with the preset facial features, outputting alarm information. The invention also discloses the air conditioner. According to the security monitoring method based on the air conditioner, the figure of the moving people is accurately captured, more favorable insurance is provided for extraction and recognition of the facial features of the moving people, and effective monitoring in the room is achieved.

A voltage controlled oscillator (VCO) conducts current on two paths through parallel inductors and parallel cross-coupled metal-oxide-semiconductor transistors. A pair of varactors are connected in series on a third path extending from a node between one inductor and one transistor to a node between the other inductor and the other transistor. The oscillation frequency is controlled by a voltage applied to a node between the two varactors on the third path. Each varactor is structured as a metal-oxide-semiconductor transistor with interconnected source and drain electrodes, a gate electrode, a body region below the gate electrode, and a body terminal region extending beyond the gate electrode. An adjustment voltage applied to the body terminal region shifts the voltage-capacitance curve of the varactor and the voltage-frequency curve of the VCO without changing the shapes of these curves, providing a simple way to adjust the VCO to meet application requirements.

The invention relates to a DC fault arc detection method. The method is characterized by comprising the following steps of 1, sampling, filtering and conducting the fast Fourier transformation on an input current of a high-frequency power electronic converter to obtain an amplitude-versus-frequency curve for the high-frequency components of the current; 2, selecting at least one frequency band containing a switching frequency or a multiple frequency from the amplitude-versus-frequency curve, and calculating the peak value D1 of the magnitude of the curve and the mean value D2 of the magnitude of the curve within the selected frequency band. Based on the change of the distance between the peak value D1 and the mean value D2, whether an arc is generated or not can be judged. If the mean value D2 gets closer to the peak value D1, the arc is judged to be generated. Otherwise, no arc is generated. According to the novel DC fault arc detection method, based on the own characteristics of the converter, noise signals are generated by the high-frequency components of the direct current at the frequency multiplication points of the switching frequency of the converter. By utilizing the noise signals, the arc spectrum of an arc fault can be analyzed and calculated. In this way, whether the arc fault occurs or not can be detected.

The invention relates to a frequency safety online monitoring and assessment method of a power system, which comprises the following steps: (1) setting a transient frequency safety binary table (fcr, fcr); (2) acquiring real-time frequency data of all monitoring points of the power system from an energy management system (EMS); (3) filtering the dynamic frequency data of all the monitoring points on the basis of a moving average method; (4) primarily analyzing the frequency data; (5) analyzing every group of dynamic frequency data, and calculating a frequency safety margin index according to the relationship between a frequency curve and the binary table (fcr, fcr) by the following three conditions: (1) tb = 0; (2) 0 < tb < tcr; and (3) tb > tcr, wherein tb is time that the frequency curve in an observation window deviates from fcr, and a frequency safety quantitative assessment method which takes frequency deviation cumulative effect is applied to the frequency safety margin calculation; and (6) comprehensively analyzing the frequency safety margin calculation results of all the monitoring points, taking the minimum margin value as a system frequency safety margin, and feeding back the system frequency safety margin to the energy management system for information display.

The invention discloses an unsmooth dynamic compensation method for an ultralow-frequency horizontal vibration table guide rail. The unsmooth dynamic compensation method comprises the following steps: measuring unsmooth dynamic characteristics of the ultralow-frequency horizontal vibration table guide rail and output uori t of a calibrated acceleration sensor in real time by taking a horizontal direction as reference; constructing a guide rail unsmoothness dynamic compensation system, and removing a gravitational acceleration component in the output of the calibrated sensor generated by pitching of a sliding table from the original output of the calibrated sensor in real time in the vibration calibration process; calibrating a calibrated acceleration sensor by adopting the compensated output ucomt of the calibrated sensor, calculating to obtain a compensated amplitude-frequency curve, and finishing vibration calibration of the calibrated sensor. The unsmooth dynamic compensation method has the advantages that the calibration result deviation of the acceleration sensor with zero frequency response caused by guide rail unsmoothness based on the ultralow-frequency horizontal vibration table can be compensated in real time in the vibration calibration process, so that the precision of ultralow-frequency vibration calibration is improved.

The invention discloses a method for predicting residual service life of an asphalt pavement according to fatigue-modulus comprehensive performance of a core sample. The method comprises the following steps: boring a core and sampling at a typical disease position of an asphalt pavement; determining resilience modulus of the core sample under the action of dynamic loading; determining a deformation-cyclic loading frequency curve for a core sample fatigue test; modeling to predict the residual service life of the asphalt pavement. The method further comprises a step of combining with a temperature factor to obtain the practical life of the pavement, and further comprises a step of combining with a traffic factor to obtain the practical life of the pavement. According to the method provided by the invention, the viscoelastic property of an asphalt mixture is comprehensively considered; due to the dynamic loading action, the practical stress situation of the pavement is stimulated, the modulus of different positions is analyzed and compared, the residual service of the pavement is described by a fatigue curve, quantitative residual life prediction is provided for maintenance of an asphalt concrete pavement, and randomness of the selection on pavement maintenance time for a long time can be overcome.

The invention discloses a method for re-sampling vibration signals of a rotary machine in angular domains on the basis of instantaneous frequency estimation, and relates to a method for diagnosing and managing mechanical faults. The method includes acquiring the vibration signals of the rotary machine, performing down-sampling on the vibration signals in time domains, computing instantaneous frequencies of the vibration signals, dividing instantaneous frequency sequences, fitting an instantaneous frequency curve, computing sampling moment sequences of the signals in the angular domains and computing amplitude sequences corresponding to sampling moments of the signals in the angular domains; computing the amplitude sequences corresponding to the sampling moments of the signals in the angular domains by a Lagrange interpolation algorithm, solving corresponding amplitude sequences A(t) corresponding to original signals at re-sampling moments and finally acquiring re-sampled signals R(t) of the vibration signals in the angular domains. The method has the advantages that an extra tachometer for extracting rotation speed information is omitted, the rotation information of a rotary shaft can be directly acquired from the vibration signals, the analytical precision is high, the cost of hardware is low, and the method is unlimited by environments and specifically has a significance in technological transformation for existing equipment of enterprises.

The invention provides a frequency mixing nonlinear ultrasonic detection method for structure microcracks based on bispectrum analysis, and belongs to the detection field of nondestructive examination. The method comprises the steps of firstly, obtaining an amplitude-versus-frequency curve of an excited probe and an excited receiving probe through frequency sweep experiments, and determining probe excitation frequency or range according to the amplitude-versus-frequency curve; then, carrying out different lateral excitation frequency mixing mode experiments, tracking difference frequency and sum frequency signals, and determining an optimal frequency of the excitation signals according to amplitude-versus-frequency response characteristics of the difference frequency and sum frequency signals; performing bispectrum analysis on the time domain signals at the optimal frequency, and determining whether structure microcracks exist in a test piece or not according to whether mixing components appear in the bispectra or not; and scanning the length direction of a test piece and tracking the difference frequency and sum frequency signals by changing time delay of the excitation signals, and determining the positions of the structure microcracks according to the amplitude-versus-frequency response characteristics of the difference frequency and sum frequency signals. Influences on experimental results caused by nonlinearity of an experiment apparatus can be prevented by employing two probes to excite the signals; and the positions of the structure microcracks can be identified by making the two signals encountered through controlling the delay time of the excited signals.

The invention relates to the technical field of sound boxes, in particular to a sound debugging method and device based on an amplitude-frequency response curve; the method comprises the following steps: acquiring an audio signal acquired by a microphone, generating a measurement amplitude-frequency response curve of the audio signal, and then, taking a preset standard amplitude-frequency responsecurve as a reference, debugging the measurement amplitude-frequency response curve according to an amplitude-frequency curve fitting target curve algorithm, obtaining a target amplitude-frequency response curve, obtaining corresponding DSP parameters of the target amplitude-frequency response curve, setting the DSP parameters to a sound box DSP, so as to complete debugging of the sound box in a sound system. Therefore, according to the embodiments of the invention, the sound debugging operation can be simplified, and the debugging efficiency is improved.