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 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 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.

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 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 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 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.