147 results about "Current spectrum" patented technology

A system and method for detecting cavitation in pumps for fixed and variable supply frequency applications is disclosed. The system includes a controller having a processor programmed to repeatedly receive real-time operating current data from a motor driving a pump, generate a current frequency spectrum from the current data, and analyze current data within a pair of signature frequency bands of the current frequency spectrum. The processor is further programmed to repeatedly determine fault signatures as a function of the current data within the pair of signature frequency bands, repeatedly determine fault indices based on the fault signatures and a dynamic reference signature, compare the fault indices to a reference index, and identify a cavitation condition in a pump based on a comparison between the reference index and a current fault index.

A system and method for iterative condition monitoring and fault diagnosis of an electric machine, such as an electric motor, is configured to iteratively analyze a pattern of multiple fault signatures in a motor current signal under harsh, noisy conditions. As such, the present invention evaluates patterns of multiple fault signatures that are spread over the wide motor current spectrum, by effectively rejecting signal distortions, harsh noise, and interference from the dynamic operation of the electric machine.

The present invention is directed an ultrasonic frequencies fault detecting apparatus. The present invention uses high frequency ultrasonic energy signals to analyze bearings and determine the presence of faults therein. The ultrasonic return signals are heterodyned (by amplitude demodulation) into the audio spectrum for purposes of audio detection. In addition, a FFT spectrum of the signal is displayed on a monitor for more accurate results. According to the present invention software is used to automatically analyze the FFT spectrum by comparing the current spectrum with stored spectrums of known bearing conditions as modified based on the rotary speed of the bearing and the number of balls. Once a defect in a bearing has been located in this manner using automated FFT analysis, an operator can then use a device, such as a calibrated lubricant dispenser, to effectuate maintenance and/or repair.

The invention relates to a two-slit interference fringe decoding spectrum confocal displacement sensor and a displacement measurement method thereof. A grating spectrometer is used in a spectrum analyzing unit of a current spectrum confocal displacement sensor, the beam split principle is complex, cost is high, detected wavelength can drift along with time and environment, and the measuring accuracy of the sensor is affected. The sensor comprises a broadband point light source, a non-aberration spectroscope, a dispersing lens group, a confocal pinhole, a non-aberration collimating lens, an interference two-slit screen, an adaptive lens, a rectangular diaphragm and a linear array CCD. Reflected light of the surface of a measured object is subjected to filtering through the confocal pinhole, then quasi-monochromatic light is formed, after non-aberration collimating, the quasi-monochromatic light is divided into two sub column face light sources by two slits, interference is formed, the widths of the interference fringes and the wavelength of the reflected light of the surface of the measured object are in good linear relation, and by interpreting the widths of the interference fringes, measuring of object displacement is achieved. The displacement sensor and the method have the advantages of being low in cost, good in linearity and high in resolution ratio, and meanwhile an instrument is simple in structure and easy to machine.

The invention discloses an asynchronous motor rotor broken bar fault judgment method with electric signals and vibration signals integrated, which belongs to the field of motor fault judgment. The method comprises the following steps: an acquisition instrument acquires voltage and current data through a current clamp and a voltage clamp, current spectrum analysis is carried out, if the current signals are normal, no broken bar fault happens to the motor rotor, and if the current signals are abnormal and when one side band appears at each position with a twice slip frequency difference from a power frequency, the next step is carried out; voltage spectrum analysis is carried out, if the voltage signals are normal, no broken bar fault happens to the motor rotor, if the voltage signals are abnormal and when one side band appears at each position with a twice slip frequency difference from the power frequency, vibration signal analysis is carried out, and whether broken bar fault happens to the motor is judged. In view of the problem that error judgment exists in a motor current signal analysis method in the asynchronous motor rotor broken bar fault in the prior art, a mode of sequentially judging the stator current, the stator voltage and the vibration signals is adopted, the rotor broken bar fault is detected, and the error judgment rate is reduced.

The invention provides a Hanning self-multiplying convolution window FFT tri-spectrum line interpolation harmonic analysis method. The method comprises the steps that 1, a voltage signal and a currentsignal are acquired according to the sampling frequency; 2, a Hanning self-multiplying convolution window function is applied to the voltage signal and the current signal separately, and FFT transform is conducted on the voltage signal and the current signal to obtain a corresponding voltage spectrum and a corresponding current spectrum; 3, maximum spectrum lines at detected peaks of fundamentalwaves and harmonic waves of the voltage spectrum and the current spectrum and amplitude values of two spectrum lines adjacent to each maximum spectrum line are detection separately; 4, amplitude values, phases and frequencies of the fundamental waves and the harmonic waves of the voltage spectrum and the current spectrum are calculated; and 5, electric energies and a total electric energy of the fundamental waves and the harmonic waves of the voltage spectrum and the current spectrum are calculated. According to the Hanning self-multiplying convolution window FFT tri-spectrum line interpolation harmonic analysis method, the calculation precision on the electric energy of the fundamental waves and the harmonic waves can be improved, and the calculation stability of an electric energy measurement algorithm can be improved.

The invention discloses the concrete steps of analysing method for coal element, which is based on the GenBank least square method and adopting a scintillation detector as the recording device and adopts the spectrum based least square method to make the spectrum analysis so as to avoid errors caused by current spectrum analysis technology and the structure of the on-line detecting device meet the necessity of the method. It adopts all of the information of gamma energy spectrum so as to avoid the error caused by spectrum stripping technology and enhance the sensitivity of detection, the reliability of measurement and the stability of the device.

Inhibitors of microbial heme oxygenase and their use for treatment of microbial infections and bioremediation. The inhibitors of microbial heme oxygenase are useful against a new class of antimicrobial agents to target infections that are persistently difficult to combat with the current spectrum of antimicrobial agents. Screening methods for selecting inhibitors of microbial heme oxygenase.

In a method magnetic resonance apparatus for the determination of k-space positions for modeling of RF pulses for magnetic resonance excitations, the following steps are implemented:

• • (a) select a target magnetization,
  • (b) select a first achievable magnetization as a current achievable magnetization,
  • (c) determine a deviation of the current achievable magnetization from the target magnetization,
  • (d) determine the spectrum of the deviation in k-space as a current spectrum,
  • (e) localize at least one maximum in the current spectrum,
  • (f) store the k-space positions of the localized maxima in a set of previously determined k-space positions,
  • (g) determine current pulse coefficients with which an optimal, current magnetization can be achieved using at least one k-space position from the set of previously determined k-space positions, and
  • (h) repeat (c) through (g) until a predeterminable termination criterion is satisfied (however at least once), wherein in each repetition at least one k-space position is used in the determination of current pulse coefficients that was used in none of the preceding determinations of current pulse coefficients.

The invention relates to a high accuracy measurement system of the line width of a narrow line width laser. The high accuracy measurement system comprises a first optical coupler and a second optical coupler; an a port of the first optical coupler is connected with a laser light source to be measured; a b port of the first optical coupler is connected with a signal receiving unit through a photoelectric detector; a c port of the first optical coupler is connected with an f port of the second optical coupler through an isolator; a d port of the first optical coupler is connected with an e port of the second optical coupler; a g port of the second optical coupler is connected with the reflecting surface through an optical fiber delay line; a beat frequency signal is generated by the light which is fed back through the outer chamber of the reflecting surface to pass through the optical fiber delay line twice and the light of the f port of the second optical coupler through the g port of the second optical coupler; the beat frequency signal is output through the b port of the first optical coupler and converted into a current signal through the photoelectric detector; the current signal is received by the signal receiving unit and a corresponding lorentz linear light current spectrum line is obtained; the full width half maximum of the light current spectrum line is the line width of the laser light source to be measured. The high accuracy measurement system of the line width of the narrow line width laser has the advantages of being simple and compact in structure, easy to implement, low in cost and high in accuracy.

The invention discloses a method for predicting a frequency spectrum of a CRN (Cognitive Radio Network) on the basis of a GCV-RBF neural network. The method comprises the following steps of: S1: acquiring channel historical data information; S2: using the channel historical data information as a preset input sample of an RBF neural network, training the RBF neural network by an OLS algorithm, and acquiring an optimal RBF neural network structure by a GCV evaluation method; and S3: according to the channel historical data information, by the optimal RBF neural network structure, predicting a current frequency spectrum state. Compared to the prior art, according to the invention, the optimal RBF neural network structure is obtained by the GCV evaluation method, so that the problem of overfitting in the training process is solved, and prediction accuracy is improved. Further, the RBF neural network structure, as a local approaching network, has the advantages of simple structure, high convergence rate, high real-time performance and the like, and can be sufficiently adaptive to changes of the network and improve self-adaptation of the network.

A scene is imaged onto a spatial light modulator. The scene is captured by collecting a pan-chromatic image using a pan-chromatic camera. An object in the scene is detected based on one of physical motion or hyperspectral detection. A spectral measurement of the scene is performed using a hyperspectral image spectrometer. A current position, a current positional velocity, and a current positional acceleration of the object is tracked. An estimated position, an estimated positional velocity, and an estimated positional acceleration of the object for a future time is estimated. A current spectrum, a current effective spectral velocity, and a current effective spectral acceleration of the object is tracked. An estimated spectrum, an estimated effective spectral velocity, and an estimated effective spectral acceleration of the object for a future time are estimated. An orientation of the spatial light modulator is controlled based on at least one of the estimated position, the estimated positional velocity, the estimated positional acceleration, the current spectrum, the current effective spectral velocity, and the current effective spectral acceleration of the object. Optionally, the spatial light modulator is a digital micromirror device.

The invention relates to a simple test system for new energy vehicle radiation harassment risk assessment. The system comprises an EMI probe used for obtaining EMI data which is noise source current spectrum data of parts and cables installed in a vehicle and ascertaining an electromagnetic interference source and an electromagnetic coupling path in electromagnetic compatibility three elements, and a spectrum analyzer or receiver 4 for displaying the rule of the change of a voltage amplitude with frequencies and measuring the interference strength of each frequency. The EMI probe is connected to the spectrum analyzer or receiver 4 through a coaxial cable 3. The simple test system of the invention has the advantages of simple equipment and convenient operation and maintenance, an EMI problem in a vehicle test can be timely found and improved, the one-time passing rate of the vehicle is ensured, and the cost of vehicle EMC rectification and testing is saved.

The invention discloses a conductive common-mode/differential-mode noise separation method, belonging to the technical field of conductive electromagnetic compatibility noise measurement. Radiofrequency current probe measurement and software separation calculation are combined, and the method is suitable for conductive interference measurement on a single phase line. The method comprises the following measuring steps: I, directly measuring a phase line, center line and common-mode conducted interference spectrum by using a radiofrequency current probe, connecting the output end of the current probe to a spectrometer through a coaxial line, and driving the spectrometer to work in a peak detection mode; II, calibrating interference spectrum data obtained in the step I, and measuring the transmission admittance of the current probe and the coaxial line used in the step I by using a vector network analyzer; III, putting the corrected data IL, IN and ICM into a formula to obtain a differential-mode current spectrum IDM so as to obtain the interference voltage in a differential mode and a common mode. By adopting a test method, the conducted interference spectrum on each line can be measured rapidly, and separation of common-mode and differential-mode interference is realized. The method is mainly applied to online measurement of electromagnetic compatibility noise.

The invention relates to a distribution network high-impedance fault location and simulation method based on integrated empirical mode decomposition, comprising the following steps: collecting the phase voltage and the phase current of a measurement point, and calculating the zero-sequence voltage and the zero-sequence current; decomposing the zero-sequence voltage and the zero-sequence current through an integrated empirical mode decomposition method, and screening a series of intrinsic mode functions reflecting transient fault characteristics; and calculating the zero-sequence voltage spectrum and the zero-sequence current spectrum according to the intrinsic mode functions, and determining the location of a high-impedance fault of a distribution network. According to the invention, a discrete analysis is made of the zero-sequence voltages of buses and the zero-sequence currents of feeders obtained through acquisition and transformation by use of an integrated empirical mode decomposition method. Calculation is quick. A high-impedance grounding fault can be detected sensitively and selectively, and detection is not affected by random factors such as transition resistance and fault time.

Embodiments described herein relate to methods of detecting an endpoint for a target substrate during chemical mechanical polishing process. In one embodiment, the method includes polishing one or more target substrates at a first film removal rate to provide reference spectra, polishing one or more target substrates at a second film removal rate to provide current spectra of the one or more target substrates, wherein the second film removal rate is different from the first film removal rate, identifying an interface transition between different layers formed on the one or more target substrates using a sequence of endpoint values obtained based on the reference spectra collected during polishing of the one or more reference substrates, and comparing each current spectrum obtained from current spectra of the one or more target substrates to the reference spectra to obtain the sequence of endpoint values. After identifying the interface transition between different layers formed on the one or more target substrates, the one or more target substrates is optionally overpolished to past a target polishing thickness.

The invention discloses a multiple concurrent wireless frequency spectrum monitoring method, mainly solving the problem that a receiver in a current frequency spectrum monitoring system only supports unidirectional connection with a client, but does not support multiple clients to simultaneously send commands to the receiver; and a current frequency spectrum analysis method is more and more difficult to truly reflect a complex frequency spectrum situation. The method comprises the steps of: (1) building a multiple concurrent server supporting one main thread and four work threads based on a libevent framework; (2) constructing a monitoring system; (3) configuring task parameters; (4) the receiver collecting data; (5) the multiple concurrent server employing the Multiquadric method in an interpolation method to stimulate the frequency spectrum data transmitted by the receiver; and (6) drafting a frequency spectrum situation graph through color mapping. According to the scheme, the method achieves the purposes of simple operation, convenient enforcement, safety and reliability, and has high use value and popularization value.

The invention discloses a decision-making method of a spectrum sensing interval in a cognitive radio network. The method comprises the following steps: obtaining a current spectrum sensing result; if the current spectrum sensing result is that a spectrum is busy and the corresponding spectrum sensing interval is theta1, calculating an expected value fT(theta1) of a reduced throughput capacity according to an expected value fO(theta1) of an idle slot time quantity when a spectrum state in the spectrum sensing interval turns to be idle; then calculating sensing energy consumption fE(theta1) of each time slot in average; calculating an optimal spectrum sensing interval according to the calculated fT(theta1) and fE(theta1); if the current spectrum sensing result is that the spectrum is idle and the corresponding spectrum sensing interval is theta0, calculating an expected value gT(theta0) of a reduced throughput capacity and an expected value gI(theta0) of interference suffered by an authorized user according to an expected value gO(theta0) of an idle slot time quantity when a spectrum state in the spectrum sensing interval turns to be busy; then calculating sensing energy consumption gE(theta0) of each time slot in average; and calculating an optimal spectrum sensing interval according to the calculated gE(theta0), gT(theta0) and gI(theta0). With the adoption of the method disclosed by the invention, the energy consumption of the system is reduced and the system throughput capacity is improved.