165 results about "Signal modeling" patented technology

A metrology target design may be optimized using inputs including metrology target design information, substrate information, process information, and metrology system information. Acquisition of a metrology signal with a metrology system may be modeled using the inputs to generate one or more optical characteristics of the metrology target. A metrology algorithm may be applied to the characteristics to determine a predicted accuracy and precision of measurements of the metrology target made by the metrology system. Part of the information relating to the metrology target design may be modified and the signal modeling and metrology algorithm may be repeated to optimize the accuracy and precision of the one or more measurements. The metrology target design may be displayed or stored after the accuracy and precision are optimized.

A transmission signal to be transmitted from a radio transmitter is predistorted in order to compensate for the signal distortion caused by a power amplifier. The transmission signal and a signal modeling a power supply voltage applied to the power amplifier are compared with distortion properties of the power amplifier using these signals. The distortion information is comprised in an amplitude distortion lookup table and a phase distortion lookup table. Transmission signal and power supply signal values are associated with envelope and phase predistortion information comprised in the respective lookup tables and the envelope and the phase of the transmission signal is predistorted accordingly.

According to various embodiments of the invention, a new and effective keyboard click noise reduction scheme is presented. The keyboard click noise reduction scheme may have various processing units including: Dynamic Signal Modeler, Smart Model Selector, Adaptive Filtering Module, Keyboard / Impulse Noise and Voice Activity Detectors, and a Post-Processing Unit. By adaptively changing the coefficients of the proposed adaptive filter through minimizing the output energy, the scheme can provide the target signal / voice with nearly zero keyboard click noise. The scheme could be used in real-time to minimize keyboard click noise or any kind of unwanted noise, especially noise having transient impulse characteristics.

The invention provides a novel microgrid system based on phase compensation and selective virtual impedance, a power balance control strategy and a small-signal modeling method therefor. The novel microgrid system comprises two paths of DG (distributed generation) units connected with an alternating current bus in parallel, a three-phase balance resistance load and a non-linear load; the DG unit comprises a distributed power supply, an inverter, an LCL type filter circuit, line impedance, two inverter primary strategy control modules and a secondary strategy control module that are connected in sequence; a first DG unit is connected with the alternating current bus through a first static switch; a second DG unit is connected with the alternating current bus through a second line impedance; and the three-phase balance resistance load and the non-linear load are connected with the alternating current bus through a second static switch and a third static switch separately. The invention provides a wattless and harmonic power balance control method for the novel microgrid system based on phase compensation droop control, selective virtual impedance and secondary control; and the wattless and harmonic power sharing of the microgrid under the nonlinear load can be effectively realized.

The invention discloses a real beam scanning radar front-view super-resolution imaging method, which belongs to a method for realizing scanning radar front-view super-resolution imaging by using the total variation functional of the scattering coefficient of an imaging region as de-convolution of priori information. A scanning radar azimuth echo signal is modeled into a result obtained by superimposing noise onto the convolution of a sampling sequence of antenna beam along the azimuth and a sampling sequence of a target reflectance distribution function along the azimuth, and a problem of scanning radar front-view super-resolution imaging is converted into a de-convolution problem; then, the total variation functional of the scattering coefficient of an imaging region is integrated into priori information of the de-convolution problem, and the de-convolution problem is converted into a constrained optimization problem; and finally, a global optimal solution to the constrained optimization problem is obtained through a cross iteration method, and scanning radar front-view super-resolution imaging is realized.

The invention relates to an MEMS accelerometer with the temperature compensation function. The MEMS accelerometer with the temperature compensation function comprises an acceleration sensor, a temperature sensor and a temperature compensation chip, wherein the acceleration sensor and the temperature sensor are connected with the temperature compensation chip. A temperature compensation method adopted by the temperature compensation chip comprises the steps that (1), zero biases and a set of output values of a scale factor are measured under a plurality of temperature points, the zero biases and the output values are fitted to be a fitting surface, and a series of fitting coefficients are obtained and arranged to be a coefficient matrix; (2), modeling is carried out on output signals of the acceleration sensor and the output signals of the temperature sensor so as to be expressed as a model matrix; (3), dot product is carried out on the coefficient matrix and the model matrix so as to obtain an output formula after the acceleration sensor obtains the temperature compensation; (4), the fitting coefficients and the output formula are written into the temperature compensation chip to be calculated. Through three-dimensional fitting of the surface and compensation after calculation, influence on a system from errors generated when the accelerometer is assembled and installed is reduced effectively.

An industrial robot diagnostic method including performing a condition analysis utilizing at least two selected input signals, wherein each selected input signal indicates a condition related to a property of the industrial robot, performing an analysis of any combination of the selected input signals utilizing a signal modeling of the signals and outputting from the condition analyzer a result being at least one of: a detection of a malfunction of the robot system, an identification of a root cause failure in the robot system and prediction of a potential malfunction in the robot system. Also an industrial robot system utilizing the method.

The invention relates to a method and a system for modeling I-UWB (Impulse-Ultra Wide Band) signal multipath transmission characteristics in an indoor visual range environment. The method comprises the following steps: dividing the I-UWB multipath signals into two confirmed clusters, each of which is provided with random arrival multipath rays; inputting the confirmed parameter which includes a multipath gain Alpha 0,0 of the initial ray of the first cluster, a multipath gain Alpha 0,1 of the initial ray of the second cluster, and the relative time delay Tm of the first and the second clusters; inputting the statistical parameters which includes the multipath arrival factor Lambada, the damped exponential Gamma of the multipath mean power and the logarithmic normal distribution standard deviation Sigma of the multipath gain of all the multipath rays which arrive subsequently in each cluster; initializing the functions of logarithmic normal distribution and exponential distribution; generating the first cluster and the second cluster; sorting the arrived multipath rays by the time sequence; and outputting the channel impulse response. The invention realizes the simplified I-UWB signal multipath transmission model, which has higher forecasting accuracy and is suitable for the indoor visual range environment without a plurality of environment topological data.

The invention discloses a PLL small signal modeling method in a double-end MMC-HVDC system. The method includes firstly obtaining the conversion relation of the electric quantity of the AC lines at both ends of the converter transformer; according to the control block diagram of a phase-locked loop, taking the voltage phase angle of the common node PCC and the output phase angle of the phase-locked loop as variables to construct a small-signal model of the phase-locked loop; according to the power current equation, obtaining the expression analysis formula of the voltage drop and the voltage phase angle difference at both ends of the AC branch connected with the converter; obtaining the linear expression of the voltage phase angle of the PCC point; and obtaining the small-signal mode complete expression of the phase-locked loop. Taking the voltage phase angle of the common point as the variable, and considering the common point voltage phase angle change caused by the equivalent impedance of the AC network connected with the converter, the change of two-phase synchronized rotation reference coordinate system rotating speed under the small disturbance can be reflected, and the model precision is improved.

The invention discloses an impedance modeling and stability analysis method of a current controlled virtual synchronous generator. In consideration of the influence of the active controller, the reactive controller, the current inner loop control and the phase locked loop of the current controlled virtual synchronous generator, a wideband small signal modeling method for current controlled virtualsynchronous generator based on sequence impedance model is provide to solve the problem of small signal impedance modeling of current controlled virtual synchronous generator. Based on a built wideband small signal impedance model, a grid impedance model and a Nyquist stability criterion, the influence of grid impedance, current controlled virtual synchronous generator grid-connected number and phase-locked loop control bandwidth on system stability is analyzed. The invention provides a model and method for analyzing the small disturbance stability in scenes of the current controlled virtualsynchronous generator connected to a micro grid and a new energy field station.

The invention discloses a coprime MIMO radar arrival direction estimation method based on multi-sample snapshots and set array signal discrete Fourier transform. The method mainly solves the problem that the calculation complexity of an existing method is high. The method comprises the steps that a homogeneous MIMO radar structure is established; reflected signals are received through a radar receiving sub-array, and modeling is carried out on radar output signals; the coprimey MIMO radar multi-sample snapshots and set array receiving signals are constructed; zero padding is carried out on themulti-sample snapshots and the set array receiving signals; the multi-sample snapshots and the set array receiving signals obtained after zero padding are subjected to sidelobe suppression; the multi-sample snapshots and the set array receiving signals obtained after filtering are subjected to discrete Fourier transform to construct a spatial spectrum; arrival direction estimation is conducted according to the obtained spatial spectrum. A larger array aperture is obtained under the condition that the number of physical array elements is certain, and the calculation complexity of arrival direction estimation is reduced.

The invention relates to a multi-terminal flexible direct current system droop coefficient optimization method based on small signal modeling. The method comprises the steps of 1, determining a systemstructure; 2, modeling a transmitting terminal converter station; 3, modeling a receiving terminal converter station; 4, modeling a direct current network; 5, carrying out small signal model operation to obtain a state matrix A of a full system model, and calculating an eigenvalue lambda; 6, analyzing small signal parameters; and 7, carrying out optimization selection on the parameters.

A method includes filtering, at a speech encoder, an audio signal into a first group of sub-bands within a first frequency range and a second group of sub-bands within a second frequency range. The method also includes generating a harmonically extended signal based on the first group of sub-bands. The method further includes generating a third group of sub-bands based, at least in part, on the harmonically extended signal. The third group of sub-bands corresponds to the second group of sub-bands. The method also includes determining a first adjustment parameter for a first sub-band in the third group of sub-bands or a second adjustment parameter for a second sub-band in the third group of sub-bands. The first adjustment parameter is based on a metric of a first sub-band in the second group of sub-bands, and the second adjustment parameter is based on a metric of a second sub-band in the second group of sub-bands.

The invention discloses a novel double-loop control method for a dual-active bridge DC / DC converter based on double phase-shift control. Under a double phase-shift control mode, a transfer function from the internal and external phase-shift angles to output voltage in different operating modes are obtained by using a small signal modeling technique in order to guide the inner-loop design of the dual-active bridge DC / DC converter. By establishing a relation between a loss model and peak current in different operating modes, the internal and external phase-shift angles in different operating modes during the optimal peak current are obtained so as to guide the outer-loop design of the dual-active bridge DC / DC converter. The use of a double-loop control compensation system can increase the cutoff frequency of the system, can greatly improve the dynamic response of the system, can reduce the static error of the system, and can realize the fast response speed and precision. The control method of replacing the optical loss with the optical peak current can simplify controller design and realize the real-time control of the converter.

The invention discloses a multi-target robust fractional frequency control method for an independent micro-grid. Small signal frequency response models of various components of an independent micro-grid system are built through a small signal modeling method; a robust loop shaping fractional frequency control model of the independent micro-grid system is built on the basis of the small signal frequency response models; the minimum accumulated sum of products of frequency deviations of the independent micro-grid system and time, the minimum accumulated sum of the products of power deviations of the system and the time, the minimum infinite norm of a robust loop shaping system matrix function and the minimum output signal value of a robust controller are taken as optimized objective functions for estimating the performance of the robust frequency controller; and an adaptive multi-objective constraint optimization solver is designed for efficiently achieving optimal setting of robust loop shaping frequency control parameters by employing the conditions that a robust stability performance index and an interference suppression performance index are smaller than 1 as constraint conditions. By the multi-target robust frequency control method for the independent micro-grid, robust frequency control on multi-performance index compromise optimization of the independent micro-grid system can be achieved.

The invention discloses a fast estimation method for a non-uniform rotating target motion parameter. The method comprises specific steps: an echo signal in a single distance unit is modeled into a QFMsignal; a correlation function is constructed, the QFM signal is converted to a time-chirp distribution plane, and minimum entropy criterion-based weighted least squares Radon transform is adopted toestimate secondary chirp; the estimation accuracy and the robustness of the algorithm in a low signal-to-noise ratio environment are improved effectively at the same time; TFD-based weighted least squares Radon transform is adopted to estimate linear chirp, and through filtering, cross-term interference is eliminated; and according to the geometric information in a distance-Doppler domain, the center frequency is directly estimated. The calculation amount of the target motion parameter estimation process can be significantly reduced, the influences of transmission errors on estimation of eachmotion parameter are effectively avoided, and the final target parameter estimation precision and the ISAR imaging quality are ensured.

The invention discloses an impedance modeling and stability analysis method for a voltage-control virtual synchronous generator. The influence of a virtual synchronous generator active controller is considered in order to provide a voltage-control virtual synchronous generator broadband small-signal modeling method based on a sequence impedance model, overcoming the difficulties in voltage-controlvirtual synchronous generator small-signal impedance modeling. On the basis of an established broadband small-signal sequence impedance model, a grid impedance model and Nyquist stability criterion,the influences of grid impedance and the number of voltage-control virtual synchronous generator grid-connected units upon system stability are analyzed. The results show that in any case of high gridimpedance and the large number of the virtual synchronous generator grid-connected units, a virtual synchronous generator grid-connected system can stably run. The models and method are provided forthe small disturbance stability analysis in the scenes, such as voltage-control virtual synchronous generators connected to a grid, and new energy stations; the popularization and application of the voltage-control virtual synchronous generators are benefited.

The invention discloses a cascade DC-DC converter stability analysis method based on a describing function method. The cascade DC-DC converter stability analysis method includes the following steps: performing linear modeling on a linear part in a single-stage DC-DC converter in a cascade system through a small signal modeling method to obtain a first linear transfer function; performing nonlinear modeling on a switch link of the DC-DC converter through a describing function method to obtain a describing function; performing equivalent processing on a source converter through a converter equivalent method to obtain a second linear transfer function, and determining the stability range of a two-stage cascade DC-DC converter according to a relation between the second linear transfer function and the describing function; and performing equivalent processing on a load converter through the converter equivalent method to obtain a third linear transfer function, and determining the stability range of the two-stage cascade DC-DC converter according to a relation between the third linear transfer function and the describing function. The method of the invention can accurately determine the critical stable state of a converter system and effectively improve the accuracy of judgment results.

The invention belongs to the field of target detection and signal processing technology and discloses a GLRT-based target detection method under a plurality of heterogeneous satellites. The method comprises the steps: received signals of a reference channel and a monitoring channel is modeled, the reference channel signals are separated and are substituted into monitoring channel signals; binary hypothesis is established according to the received signal of the monitoring channel, and probability density functions of signals under two hypotheses are given out; maximum likelihood estimations of unknown parameters under two sypotheses are respectively estimated through using a maximum likelihood estimation method according to two probability density functions; according to the maximum likelihood estimations of unknown parameters, detection statistics based on a generalized likelihood ratio are obtained, and a detector is obtained; according to the probability distribution of the detection statistics, an optimal decision threshold of the detector is obtained, the judgment is performed, and the target is detected. According to the invention, the method can effectively realize moving target detection under a plurality of heterogeneous satellite radiation sources.

The invention relates to an ant colony algorithm and related matrix based optimizing method for a sequential fault diagnosis strategy. The method comprises four major steps, namely, encoding and building a model, constructing fitness functions, building a model for the sequential fault diagnosis strategy, and optimizing the model. According to the method, the multi-signal model building technology is carried out to obtain related matrix of representation system faults and test dependency, and the fitness functions, a state transition rule of the ant colony algorithm and an information feedback mechanism are defined to convert the diagnosis strategy optimization into ant colony optimization; three strategies, including dynamic adjusting of permeates, information compressing and adapting of degree of congestion are introduced for improving the rate of convergence and optimization capacity of the ant colony algorithm, and therefore, the precision of the optimal design method of the diagnosis strategy and the robustness of the results are improved. The method is consistent with the principle of the minimum cost, namely, the search cost is minimized on the premise that the fault detection rate and isolation rate are ensured, and the requirement on fault strategy optimization is met.

The invention discloses an MMC frequency coupling impedance modeling method under model prediction AC voltage control. An MMC under AC voltage control is predicted by using a model to serve as a modeling object; through circuit equation frequency domain small signal modeling and model prediction AC voltage control loop frequency domain small signal modeling, an MMC small signal impedance model isobtained through derivation, and the model is composed of MMC positive sequence impedance, MMC negative sequence impedance and positive sequence impedance and negative sequence impedance frequency coupling terms caused by MMC internal complex harmonic dynamic characteristics. The accuracy of the small signal impedance model established by the method is verified by simulation, and the method and the basis can be provided for MMC small signal impedance modeling and stability analysis based on an MMC system.

The invention discloses a photo-communication system based on a digital coherent receiver. The photo-communication system based on the digital coherent receiver comprises a laser transmitting module. Laser which is emitted by the laser transmitting module is connected with a signal input end of an optical signal filtering module through an optical signal modeling and delaying processing module. A signal output end of a filtering module is connected with a signal input end of an optical signal processing module through an optical fiber link. A signal output end of the optical signal processing module is connected with a signal input end of an integrated coherent machine receiving module. A signal output end of a local optical signal production module is connected with a local signal input end of the integrated coherent machine receiving module. The invention further provides a handling method of an output signal of the photo-communication system. The photo-communication system based on the digital coherent receiver has the advantages of being simple in structure, free from optical clock recovery, capable of using a asynchronous pulse local oscillator and capable of automatically conducting polarization compensation and polarization mode compensation, achieves high-speed transmission of signals, reduces electron loss and meanwhile guarantees precision of sampling signals. The photo-communication system based on the digital coherent receiver is suitable for an Ethernet system with a bit rate of 400 giga-bit per second (Gbps) and utilizes a photo-communication system with a 20 Hertz broadband and a 50-Herz sampling rate.

A small signal model based on a single-phase cascaded island ACHB inverter system and a stability analysis method based on a floquet theory are provided. The single-phase cascaded island ACHB invertersystem includes a digital controller with double closed loop control, an LC filter, a load and three single-phase H-bridge inverters operating at low voltage, medium voltage and high voltage respectively. The digital controller is connected to a filter capacitor. The small signal model based on the single-phase cascaded island ACHB inverter system, in consideration of a linear resistive load withsmall signal disturbance, separates a disturbance component, obtains a modulation signal expression by coordinate transformation, and analyzes the system stability by using the floquet theory. The beneficial effect is that a multi-level inverter reduces the harmonic components in the output voltage due to the increase of the output level of a main circuit, and the stability analysis of the smallsignal model solves the difficulty of modeling the nonlinear circuit of a converter, the dynamic characteristics of steady-state operating point of the converter are described by unified differentialequations, the stability domain of the system is accurately verified by the floquet theory, and a reliable criterion is provided for the stable operation of the whole single-phase cascaded island inverter system.

The invention discloses a topic-oriented multi-microblog time sequence abstracting method. The method comprises the following steps of 1) by taking a time point as a horizontal axis and a microblog updating speed corresponding to a corresponding time point as a longitudinal axis, performing topic-oriented microblog text stream popularity signal modeling; 2) denoising an initial signal in the step 1) by adopting wavelet denoising, selecting a signal maximum point in the signal according to a certain time granularity, and performing sorting according to the corresponding updating speed to detect an important time point; 3) establishing a text sorting model T2ST which reflects the importance of a microblog by fusing an instantaneous time sequence characteristic of a microblog stream popularity signal and the user social contact authority of a social network; and 4) selecting an abstract sentence by adopting a maximum edge related technology and establishing an MMR microblog abstract sentence selection model. According to the method, the important time point in a microblog sequence under a specific topic is detected through a wavelet denoising method, and based on this, multiple microblogs are abstracted by utilizing an improved graph-based random walk algorithm, so that the accuracy of an output result is high.

The invention puts forward an all Bregman divergence-based matrix constant false alarm rate detection method. A technical solution of the method comprises the following steps: a radar echo signal in each range cell is modeled into a Hermite positive definite matrix, all Bregman divergence distance between mid-values of the matrix in each range cell and corresponding matrixes of neighboring cells thereof is calculated, and whether an object exists is determined after the all Bregman divergence distance is compared with a set threshold value. The method disclosed in the invention is simple in principles and small in calculation amount, the method is not sensitive to noise particularly in conditions of large background clutters, and the method is high in detection performance.

The invention discloses a stability criterion method suitable for a multi-voltage-grade direct-current power distribution system. The impedance criterion method comprises the following steps: firstly,according to the definitions of a control bus voltage type converter and a control bus current type converter, a unified expression form of the multi-voltage-grade direct-current power distribution system is obtained; secondly, small-signal modeling is performed on each converter, output voltage and output current control modes are adopted for a direct-current transformer, and a two-port small-signal model of the multi-voltage-level direct-current power distribution system in the unified form is built; thirdly, a transfer function from input variables to output variables of the system and anequivalent loop gain expression of the system are derived; and finally, the stability of the system is judged through whether the equivalent loop gain of the system meets a Nyquist stability criterionor not, and if the equivalent loop gain meets the Nyquist stability criterion, the system is stable, otherwise, the system is not stable. The impedance ratio criterion of an existing direct-current power distribution system is popularized to the multi-voltage-grade direct-current power distribution system, so that the application range is wider.