623results about "Mitigation of undesired influences" patented technology

The derivative of a noise-containing input signal is determined by using an aliased derivative to periodically reset a filtered version of a normally determined derivative. The aliased derivative is calculated using a slower update or sampling rate than the normally determined derivative, and the filtered version of the normally determined derivative is reset to a reset value at each update of the aliased derivative. The reset value is based on a weighted sum of the aliased derivative and the filter output. The periodically reset filter output closely follows an idealized derivative of the input signal, substantially eliminating the phase delay introduced by conventional filtering.

A circuit for measuring distances and which has at least two inputs (1, 2), at least one measuring coil (3), and at least one signal source, wherein at least two input signals (epos, eneg) are generated by means of the signal source, and the inputs (1, 2) are activatable by means of the input signals (epos, eneg). The input signals (epos, eneg) are applied, preferably preprocessed, to the inputs of the measuring coil (3). The circuit is designed for use where little space is available for the circuit, with the input signals (epos, eneg) being applied to a preferably timed SC network, which generates a measuring output signal that is dependent on temperature. A corresponding method is also described.

The invention discloses a dynamic signal demodulation method for a fiber laser sensor. A sensing system is established, and comprises a beat frequency signal generation part and a signal demodulation part. The beat frequency signal generation part generates a beat frequency signal and receives a dynamic signal through a sensing probe; the original beat frequency signal is demodulated into a frequency modulation (FM) signal by the dynamic signal; the FM signal is input into the signal demodulation part and demodulated by an FM demodulator to form a modulation signal, namely, the dynamic signal; and the modulation signal is subject to analogue-digital (AD) conversion through an AD data acquisition card and then processed by a digital processing circuit to obtain the frequency and acceleration parameters of the dynamic signal. Through the invention, the dynamic signal demodulation method is free from influence of light-intensity variation, electromagnetic interference and the like; and compared with the known fiber dynamic demodulation method, the dynamic signal demodulation method is easy to implement and ensures stable and reliable operation and low cost.

In one aspect, a computer system for managing occurrences of data anomalies in a data stream is provided. The computer system includes a processor in communication with the data stream. The processor is programmed to receive a first data stream from a phasor measurement unit. The processor is also programmed to calculate at least one singular value associated with the first data stream. The processor is further programmed to detect a first data anomaly within the first data stream using the at least one singular value. The first data anomaly occurs during a first time segment. The processor is also programmed to indicate the first time segment as containing the first data anomaly.

The invention discloses a detecting method of a weak periodic signal based on a chaotic system and wavelet threshold denoising, which comprises the following steps of: firstly carrying out wavelet decomposition on collected information, and determining a decomposition scale according to an actual signal-to-noise condition; denoising a wavelet high-frequency coefficient after the wavelet decomposition, wherein in the process of wavelet threshold denoising, the selection of a threshold is an important problem and directly influences a denoising result, so that the invention firstly provides a method for determining the threshold according to the scale for carrying out coefficient threshold processing to improve the denoising effect; reconstructing a signal after denoising, merging the signal to be detected after wavelet denoising reconstruction as one part of the driving force of the chaotic system into a chaotic detecting system, further inhabiting noise interference by utilizing the characteristics of the chaotic system for strong noise immunity, periodic weak signal sensitivity and the like, and effectively extracting the weak signal. The invention improves the detection threshold and the signal-to-noise ratio purely based on the chaotic detecting system.

Methods and systems using Pade′ Approximant expansion ratios provide mappings between nonlinear sensors and a more linearized output domain. In one embodiment (a) a variable gain amplifier receives a supplied input signal, the amplifier has at least a first input terminal, an output terminal, and a gain control terminal; (b) a first summer coupled to the output terminal of the variable gain amplifier adds in a first offset signal; (c) a first multiplier coupled to an output of the first summer receives a proportional feedback factor signal and correspondingly generates a multiplied feedback; (d) a second summer coupled to an output terminal of the first multiplier adds in a corresponding second offset signal; and (e) a second multiplier coupled to an output of the second summer receives a gain factor signal and generates a multiplied gain signal; where the gain control terminal of the variable gain amplifier is operatively coupled to an output terminal of the second multiplier.

The invention discloses a method for real-time correcting error of a multi-channel high-speed parallel alternative acquisition system, which comprises the following steps: in correction, inputting direct current correction signals of different voltages, acquiring a quantization value of each ADC and performing correction point by point to obtain errors point by point and form an error matrix; in measurement, inputting a signal to be measured and performing sampling at time alternating, acquiring quantization values and searching a table in the error matrix, deducting corresponding error value from the quantization values respectively to obtain corrected actual quantization values; and then, rearranging the corrected quantization values according a time phase relationship; converting the rearranged and corrected quantization values into acquisition data for output; and performing low-pass filter; and filtering time-base deviation error spectral line so as to finish the correction of a time error. Compared with the prior art, the method has the advantages that: the deviation and a gain error can be corrected at the same time; and a table searching operation is a corresponding relationship operation of which the process is simple and the calculation amount is small. A low-pass digital filter is very easy to be implemented in a DSP processor and the operation rate is fast so that the efficiency of the time error correction is improved greatly.

The invention discloses a method for eliminating or reducing nonlinearity errors in laser heterodyne interferometry, which belongs to the technical field of light heterodyne interferometry in precision measuring technology. The method comprises a step of adding new light rays after amplitude adjustment and phase adjustment into laser beams participating in interferences, wherein the new light rays has the same frequency and amplitude as those of light signals generating the nonlinearity errors, and has reverse phases with the light signals generating the nonlinearity errors so as to counteract the interferences generated by the light signals generating the nonlinearity errors to the laser heterodyne interferometry. The method has the advantages of effectively eliminating or reducing the nonlinearity errors and improving the measurement precision.

The invention provides a double-wire differential-type magnetostrictive displacement sensor, relates to the technical field of sensors, and solves the technical problem of improving detection accuracy. A framework, a fixed block, signal generation assemblies and a measuring circuit are arranged in a casing of the sensor, wherein the framework and the fixed block are fixed at two ends of the inner wall of the casing respectively. The sensor is characterized in that: two sets of signal generation assemblies are provided; each set of the signal generation assemblies comprises a waveguide wire, an induction coil and a shielding device; one end of each waveguide wire is a near end and the other end of each waveguide wire is a far end; the near ends of two waveguide wires are arranged in two bores of the framework respectively, and the far ends of the two waveguide wires are arranged on the fixed block and connected to each other through a connection lead; the axial lines of the two waveguide wires are parallel to each other; two induction coils are coaxially wound at the peripheries of the two bores on the framework respectively and connected to the measuring circuit after being in series-opposing connection; and two shielding devices are coaxially sleeved at the peripheries of the induction coils of the assemblies respectively. The sensor provided by the invention has high detection accuracy.

The invention discloses a spontaneous Brillouin scattering optical time domain reflectometer (BOTDR) based on a superconductive nanowire single-proton detector, which is characterized in that an optical pulse emitted by an optical pulse generating unit is coupled to a sensing optical fiber through a circulator, backward scattered light scattered from the sensing optical fiber is subjected to filtration of rayleigh scattering light through an optical filter unit to obtain Brillouin scattering light, a back scattering light signal is detected by the superconductive nanowire single-proton detector, an electric signal output from the superconductive nanowire single-proton detector is acquired and processed by a data acquiring and processing unit, and finally, a result is obtained through a certain demodulation relation. Compared with the traditional BOTDR, the BOTDR provided by the invention is used for carrying out data acquisition and processing by adopting the noise equivalent power (NEP) low / no-bandwidth-limit superconductive nanowire single-proton detector as a detection unit and adopting a single-proton counting technology.

A method for improving measurement precision by using an acousto-optic device in optical heterodyne interferometry belongs to the field of measurement precision by using acousto-optic device in optical heterodyne interferometry in precise measurement technology. In the measurement precision by using acousto-optic device in optical heterodyne interferometry by using the acousto-optic device, by changing the polarization direction of the part light beam output during an acoustic-optic interaction process, for instance, by utilizing abnormal Gragg diffraction, the polarization direction of the first-order diffraction light with frequency converted is vertical to other light beams, particularly the polarization direction of the zero-order light with the frequency unconverted; therefore, the crosstalk light is extremely easy to be filtered. Alternatively, the polarization direction of the reference light beam can be adjusted so that the polarization direction of the reference light component in the signal light beam is vertical to the polarization direction of the reference light beam, thus leading the interference signal output by a detector to be the minimum. In conclusion, the difference among the useful light beam, the crosstalk light and the noise light on the polarization direction can be caused; by utilizing the difference, the method can inhibit the effect of the interference light effectively, so as to reduce nonlinearity, improve signal-to-noise ratio and improve the measurement precision by magnitude.

The present invention discloses a method of using of a programmable circuit to calibrate a transducer. The programmable circuit is coupled to or communicates with a computer and to a testing station. The computer automatically varies the conditions of the testing station and programs the programmable circuit to produce a desired response. In another embodiment, a system is presented that can be used to measure various parameters that includes a programmable that may be mounted in the same package as a sensor. Such a system may include pressure sensors that are optimized to measure very low pressures.

The invention discloses a high accuracy capacitive readout circuit with temperature compensation, belonging to the design field of integrated circuits. The circuit realizes high accuracy capacitive readout owing to the adoption of a chopping modulation technology, and can simultaneously realize temperature compensation by adjusting temperature characteristics of internal voltage reference. The circuit comprises an oscillator, a voltage reference source, a full-differential operational amplification unit, a common-mode operational amplification unit, a low pass filter, a switch device and a digital circuit. The voltage reference source generates a square wave in cooperation with a single-pole double throw switch, and the square wave is applied to an intermediate polar plate of a differential capacitance to be detected in order to implement modulation. The full-differential operational amplification unit and a feedback capacitance constitute a charge integrator to detect a transfer charge formed by the variation of the capacitance to be detected. Demodulation is realized by the switch device and the low pass filter. Both an input end and an output end of the full-differential operational amplification unit are set through a switch cycle. The common-mode operational amplification unit and the feedback capacitance constitute a common-mode feedback loop which is connected with the input end of the full-differential operational amplification unit to play the role of inputting common-mode voltage stably.

In one aspect, a computer system for managing occurrences of data anomalies in a data stream is provided. The computer system includes a processor in communication with the data stream. The processor is programmed to receive a first data stream from a phasor measurement unit. The processor is also programmed to calculate at least one singular value associated with the first data stream. The processor is further programmed to detect a first data anomaly within the first data stream using the at least one singular value. The first data anomaly occurs during a first time segment. The processor is also programmed to indicate the first time segment as containing the first data anomaly.

The utility model relates to error correction of a vector sensor, in particular to a calibration and compensation method for mounting errors between a triaxial vector sensor and a mounting carrier, which calibrates and compensates the measuring result errors of the triaxial vector sensor due to mounting errors between the triaxial vector sensor and the mounting carrier. In the method, the calibration method for the mounting angle errors-psi angle, theta angle and gamma angle is as follows: a carrier coordinate system for a sealing shell of the triaxial vector sensor is calibrated; the mounting angle errors-psi angle, theta angle and gamma angle between the triaxial vector sensor and the mounting carrier is determined; the mounting angle error-psi angle between the triaxial vector sensor and the mounting carrier is determined; and a correction maths model aiming at the mounting angle errors between the triaxial vector sensor and the mounting carrier is finally determined according to the psi angle, theta angle and gamma angle obtained through calibration. The calibration and compensation method has simple correction process and accurate result, and is applied to the triaxial vector sensor with fixed measuring vectors in a measuring environment.

A method, apparatus, and article of manufacture for analyzing measurements. The invention provides a method for separating and analyzing the components of a distribution, such as deterministic and random components. The method performs the steps of collecting data from a measurement apparatus, constructing a histogram based on the data such that the histogram defines a distribution, fitting tails regions wherein deterministic and random components and associated statistical confidence levels are estimated.

The present invention relates to a physical quantity measuring instrument and signal processing method thereof capable of reducing noise components and improving reliability without increasing size or cost of the circuit. A physical quantity detecting unit (11) has signal detecting components for detecting a plurality of signals based on a desired physical quantity and detects the desired physical quantity. A signal processing unit (12) executes signal processing of the signals detected on the individual detecting axes by the physical quantity detecting unit (11) for linearly combining the signals in different combinations with time. An arithmetic processing unit (13) combines and calculates a plurality of signals based on the physical quantity associated with the physical quantity detecting unit (11) from the signal data output by the signal processing unit (12). It can linearly combine the signals from the plurality of detecting axes in different combinations with time, output them, and obtain desired signal components whose noise components are reduced by calculating the outputs.

A slope correction signal setting unit is configured to output selectively one of a plurality of direct current signals according to the sensed temperature parameter signal. Levels of the plurality of direct current signals are determined to correspond to the predetermined temperature dependent characteristic of the sensor signal. An analog amplifying circuit is connected to the slope correction signal setting unit and configured to amplify the outputted direct current signal according to the sensed temperature parameter signal. An analog arithmetic circuit is connected to the analog amplifying circuit and configured to carry out a predetermined arithmetic operation based on the amplified direct current signal and the sensor signal.

A direct current and an alternate current are simultaneously supplied from a constant current circuit to a detection coil. At least one of the ratio of the direct current to the alternate current, the ratio of an alternate current component to a direct current component of an impedance in a detecting section, a temperature characteristic of the ratio of the direct current to the alternate current, and a temperature characteristic of the ratio of the alternate current component to the direct current component of the impedance of the detecting section is set in such a manner that the margin of fluctuation of a temperature coefficient of a peak value of an output voltage from the detecting section in a whole displacement zone of a core relative to the detection coil is smaller than the margin of fluctuation of a temperature coefficient of the alternate current component of the impedance of the detection coil at the frequency of the alternate current.

A measurement device and method for determining the angular position of a pivoting headlight by means of a measurement device that comprises at least one ferromagnetic element that emits a local magnetic field, first means of measuring the local magnetic field in projection on a first axis, the at least one ferromagnetic element being mounted so as to pivot with respect to the at least one first measurement means, and an electronic processing unit, the method comprising a measurement step, and a second processing step during which the electronic processing unit calculates the angular position of the headlight, that, during the measurement step, the intensity of the local magnetic field is measured in projection on a second axis orthogonal to a first axis, and that, during a second processing step, the electronic processing unit calculates a value representing the angle of the local magnetic field with respect to the first axis.

A method for controlling a vapor compression system determines a value of a metric of performance of the vapor compression system using a previous value of an estimated parameter and a previous value of a control signal determined for a previous time step of the control. The values of the estimated parameter represent a relationship between values of the control signal and values of the metric of performance. A current value of the estimated parameter is determined based on the previous value of the estimated parameter and an error between the determined value of the metric of performance and a measured value of the metric of performance. Next, a current value of the control signal is determined based on the current value of the estimated parameter.

A circuit that senses a process variable, comprises a voltage divider that includes first and second capacitances. At least one of the capacitances is varied by the process variable. Divider ends receive modulated potentials, and a divider center tap coupled to a detector. The detector has a detector output representing carrier frequency range components. A control circuit controls a baseband envelope of the modulated potentials as a function of the detector output.

The present invention is a sensor interface or network of interfaces that utilizes high-temperature electronics to operate at elevated temperatures for applications that include but are not limited to aircraft and automobile engines, vehicle frames, refineries, nuclear and chemical production plants, and in downhole drilling for petroleum and natural gas. The interface or network provide connectors for a variety of sensors with analog and digital outputs, and can in turn provide data to an automated electronic control system or a monitor. Because the sensor interface may be placed in so-called “hot zones” nearer to the sensors being monitored than other systems that use conventional electronics, the sensor interface can increase noise immunity, increase reliability, decrease cost, reduce weight, and increase space.

An apparatus employing a method for measuring the temperature of a sensor (Rx) having a resistance which varies in accordance with the temperature of the sensor, using a switching sequence to apply a parasitic voltage correction signal to the input of an amplifier in the measurement circuit whereby the sensor generates an offset response signal which is amplified and adjusted to substantially minimize the amplified offset response signal. The temperature of the sensor is calculated from the amplified response signal in accordance with a predetermined algorithm.

The invention discloses a sensor network sensing information denoising processing method based on principal component analysis (PCA) and empirical mode decomposition (EMD). The method comprises the following steps of: performing EMD on a sensing signal to obtain K intrinsic mode function (IMF) components imfk (t) for characterizing time scale and remainder terms; extracting detailed signal information in imf1, calculating energy W[1] of the noise contained in the imf1, and calculating energy of other layers according to W[1]; and performing PCA decomposition on imfk (t), selecting the previous H principal components in a proper number for reconstructing and denoising according to a ratio of the energy of the noise contained in the imfk(t) to obtain the denoised detailed signal information; and accumulating all the denoised detailed signal information and remainder terms to obtain the denoised signals. The method is simple and good in denoising effect.

The invention discloses a quasi-distributed sensor network based on time division multiplex and matched optical fiber grating technology, which can accommodate a plurality of groups of optical fiber grating pairs with matched central reflection wavelength in a grating sensor network. A broadband light source is directly modulated in high speed by a narrow pulse signal sequence, a light pulse emitted by the broadband light source passes through an isolator and a circulator to enter into a sensing optical fiber grating and a matched optical fiber grating sequence, the light pulse is reflected back to light pulse sequences of different time delays with variation of the position of the optical fiber grating in the transmission process, and the light pulse sequences are processed with photoelectric conversion by a photoelectric detector to form electric pulse signal sequences. Arrangement position of the pulse sequence on a time domain is relative to spatial position of the optical fiber grating in the sensor network, wherein the optical fiber grating forms reflection, so that the signal is processed based on a high speed circuit, different gratings are distinguished according to a relation of time and position of the pulse signal, and wavelength change of each sensing grating is respectively obtained according to peak intensity of the pulse signal.

The invention discloses a spontaneous Brillouin scattered light time-domain reflectometer on the basis of double laser frequency locking, which is mainly applied to the technical field of optical fiber sensing nets. The invention aims at providing a spontaneous Brillouin scattered light time-domain reflectometer with small volume, low price and stable wavelength difference between vibration light and incident light on the basis of the double-laser frequency locking. In order to solve the problems, the invention adopts the technical scheme that the spontaneous Brillouin scattered light time-domain reflectometer comprises a laser used as the incident light and a laser used as the vibration light. Light emitted by the laser used as the incident light is output to a detecting light path. After the light emitted from the detecting light path passes through an electro-optical modulator, a light amplifier and a circulator controlled by a pulser, the light enters into a sensing fiber to obtain Brillouin scattered light. The Brillouin scattered light passing the circulator and the light emitted by the laser used as the vibration light are in beat frequency interfere through a coupler. At last, electrical signals are output by a photoelectric detector and are collected and processed by a computer with a data acquisition card.

A position sensor is provided comprising a coil (1) and an electric conductor (2) or magnetic (3) both arranged so that the size of their overlapping area (p) is varied as the position of an object to be examined changes, a resistor (6), a capacitor (4), a comparator (5) of an inverse output type, and a timing circuit (50a) arranged for uniformly restraining the period (T) of a continuous oscillating motion, herein a displacement of the object to be examined is detected as a change in the time duration (t) which extends from the leading end of the period (T) to a time when the output of the comparator (5) is turned to a high level as timed with substantially the trailing end of the period (T). The resistance of the resistor (6) is determined so that a change in the time duration (t) remains minimum when the resistance of the resistor (6) is varied and when the temperature is at a predetermined degree. As the result, the linearity of the output can be improved over variation of both the temperature and the position.