30 results about "Crossover frequency" patented technology

The invention discloses a gold finger defect detection method based on mixed multi-fine-grained frequency, relates to the technical field of gold finger defect detection, and solves the technical problem that gold finger defect detection precision and stability are difficult to ensure in a complex scene. The method comprises the following steps: coding a training data set to obtain a first feature map; inputting the first feature map into a hybrid crossover frequency attention module to obtain a second feature map, and inputting the second feature map into a multi-fine-grained frequency attention module to obtain a frequency response feature map; performing pooling operation on the frequency response feature map, adding output results in a channel dimension, and outputting a double-path attention map; performing element multiplication operation on the double-path attention map and the frequency response feature map to generate a frequency enhancement feature map; decoding based on the first feature map and the frequency enhancement feature map, and outputting a golden finger prediction image; and inputting the golden finger image to be detected to obtain a detection result. The method improves the recognition capability and robustness of the key abnormal region, and improves the detection precision and stability.

An electroacoustic transducer includes a port that guides a component of at least a partial frequency band of a sound radiated from a first diaphragm in a direction opposite to a direction in which a front surface 38A of a second diaphragm faces, to an external space on a front surface side of the second diaphragm. As the port is provided, the electroacoustic transducer is configured such that a sound pressure of a synthesized sound in the vicinity of a crossover frequency of radiated sounds from the first diaphragm and the second diaphragm in a case in which a drive unit generates vibration is equal to or higher than a sound pressure of the radiated sound from only one of the first diaphragm and the second diaphragm at the crossover frequency.

The invention provides a robust design method and system for a fractional order PI controller of an inertia and delay fractional order object. The method comprises the following steps: describing a controlled object by adopting an inertia and delay fractional order transfer function; the feedback controller adopts a fractional order PI controller; a crossing frequency and a phase margin are given, and a proportional gain, an integral gain and a controller order of the fractional order PI controller are solely solved based on three constraint equations of the given crossing frequency, the given phase margin and zero slope of an open-loop phase of a closed-loop system at the crossing frequency; if a null set is solved, the values of the crossing frequency and the phase margin need to be given again, and solving is carried out; and traversing the range of the traversing frequency and the phase margin to obtain a feasible region of the fractional order PI controller. According to the method, the parameters and the feasible region of the fractional order PI controller can be directly calculated, it is guaranteed that the fractional order PI controller has high robustness, and the method has practical application value.

The present invention belongs to the technical field related to controller design, and discloses a design method and application of an ADRC controller based on a fractional-order ESO, the design method comprising the following steps: (1) determining a control object model; (2) constructing a fractional-order model corresponding to the control object, and determining the model parameters of the fractional-order model through an optimization algorithm; (3) establishing a fractional-order extended state equation of the control object; (4) adding the model parameters of the fractional-order model to an extended state observer, and then designing a fractional-order model-assisted extended observer; (5) using the total disturbance estimated by the fractional-order model-assisted extended observer to compensate the control object; (6) calculating the compensated equivalent model, and then obtaining the open-loop transfer function of the ADRC controller, and given the crossover frequency design index, calculating and determining the parameters of the feedback controller. The present invention can make the control system insensitive to input noise and robust to changes in the system loop gain.

This invention discloses a frequency-division vibration control method suitable for series-type excitation systems, including test parameter setting, system self-testing, transfer function identification, and single-frame periodic cyclic vibration control. The control method fully considers the inability of a single frequency range control mode to guarantee high-precision control for different types of excitation systems with varying frequency characteristics. It divides the entire vibration frequency band into low-frequency and high-frequency intervals, respectively, based on the frequency characteristics of the low-frequency and high-frequency stations. Different transfer function compensation and window compensation techniques are applied to different intervals. Furthermore, effective frames are extracted from the time-domain output signals using a frame extraction method, achieving smooth overlap of the system's time-domain signals. Combining the low-frequency and high-frequency station crossover frequency calculation method, the output signals of the low-frequency and high-frequency stations are superimposed to achieve stable and smooth frequency-division control of complex series-type excitation systems.

The invention provides an aero-engine strong non-stationary cross frequency signal time-frequency analysis method and system, and relates to the technical field of aero-engine signal processing and fault diagnosis, and the method comprises the steps: obtaining a vibration signal, and obtaining initial time-frequency distribution; performing adaptive ridge line extraction on the initial time-frequency distribution, and determining a time-frequency block range of an intersection region; carrying out local sub-blocking on the time frequency distribution in the intersection area to obtain optimized time frequency distribution; performing component reconstruction on the vibration signal by adopting Vold-Kalman order filtering to obtain final time frequency distribution; according to the method, the ridge line fracture time-frequency block is determined through bidirectional retrieval repair, the intersection area and the hierarchical cascade reconstruction component are optimized through comprehensive evaluation indexes, the ridge line continuity and instantaneous frequency extraction precision of the intersection area are remarkably improved, and high-resolution representation and accurate separation of strong non-stationary intersection frequency signals are achieved.

The invention relates to high-bandwidth constant on-time PWM control, the apparatus and related methods relate to dynamic bandwidth control of a variable-frequency modulation circuit through selective contribution of an XFTE in response to transients in the switching frequency. In an illustrative example, the XFTE can generate a transient control signal in response to a transient in a control output signal indicative of the switching frequency and received from a feedback control circuit. The XFTE can generate the transient control signal, for example, in accordance with a predetermined relationship between a crossover frequency of the modulation circuit and the switching frequency. The feedback control circuit can generate the control output signal, for example, from a predetermined reference and a control input signal. The control output signal can correspond to a pulse-width modulated output delivered through an inductor to a load, for example. An advantage of the invention is that the effective bandwidth of the modulation circuit can be advantageously increased while maintaining desired frequency response characteristics.

The invention discloses a switching power supply loop compensation parameter debugging method and device. The method comprises the following steps: acquiring an initial resistance value of a series equivalent resistor, a first initial capacitance value of a series equivalent capacitor and a second initial capacitance value corresponding to a parallel equivalent capacitor, and setting a corresponding series resistor, a series capacitor and a parallel capacitor in a switching power supply loop according to the initial resistance value, the first initial capacitance value and the second initial capacitance value; carrying out Bode test on the switching power supply loop by using a loop analyzer to obtain a phase margin, a gain margin and a ride-through frequency; and sequentially adjusting the capacitance value of the shunt capacitor, the capacitance value of the series capacitor and the resistance value of the series resistor according to the phase margin, the gain margin and the ride-through frequency until the capacitance value of the shunt capacitor, the capacitance value of the series capacitor and the resistance value of the series resistor which meet the judgment standard of the Bode test are obtained. Through the mode, the optimal loop compensation parameter can be debugged.

The invention discloses a robustness evaluation method for an antisymmetric coupling system, and the method comprises the following steps: building a system simulation model architecture which comprises a body dynamics link, a steering engine dynamics link and a steering engine static decoupling dynamics link; setting a steering engine dynamics link transfer function, a steering engine static decoupling dynamics link transfer function and a body dynamics link transfer function in the system simulation model; acquiring an amplitude margin, a phase margin and 0dB amplitude crossing frequency of the system simulation model, and further acquiring pure delay time of the simulation system; and mapping the obtained pure delay time into robustness evaluation of the system. According to the robustness evaluation method for the antisymmetric coupling system disclosed by the invention, accurate evaluation of the robustness of the system can be realized.

The invention provides a non-contact residual current detection method and device, terminal equipment and a storage medium. The non-contact residual current detection method comprises the following steps: acquiring a magnetic induction intensity x component test value based on a magnetoresistive sensing array, and inputting the magnetic induction intensity x component test value and an established mathematical model into a differential evolution algorithm; generating an initial population with a plurality of individuals and calculating the fitness value of each individual; selecting the individual corresponding to the minimum fitness value from all the fitness values for variation and crossover to obtain a new individual, calculating the fitness value, performing multiple times of variation and crossover on the new individual with the fitness value smaller than the minimum fitness value, and taking the individual with the variation frequency and the crossover frequency reaching the preset frequency as the optimal individual, the residual current and the wire position of the target dual-core wire are calculated through the dimension combination of the optimal individual; under the condition that the specific position of a measurement target is unknown, full-non-contact detection of residual current and position calibration of a double-core wire can be carried out without damaging a wall body or penetrating through the wire, and the detection safety and the detection precision are improved.

Presented are systems and methods for improving transient response in buck-boost circuits avoid circuit instabilities in both boost mode and buck mode. In embodiments, this is accomplished when, in response to determining that the circuit operates in buck mode, a compensation circuit is adjusted to operate at a first bandwidth. In response to determining that the circuit operates in boost mode, the compensation circuit may then be adjusted to decrease a boost mode crossover frequency and operate at a second, lower bandwidth.

A first subwoofer may be configured to output multimedia content in synchrony with at least one other playback device and a second subwoofer. The first subwoofer may, based on a received indication of an acoustic characteristic of the at least one other playback device, determine a crossover frequency of (i) the first subwoofer and the second subwoofer and (ii) the at least one other playback device. After determining the crossover frequency, the first subwoofer may output a first tone set and a second tone set in synchrony with the second subwoofer and the at least one other playback device, and after outputting the first tone set and the second tone set, receive, from a controller device, an indication of a selected one of the first tone set or the second tone set. Based on the selected tone set, the first subwoofer may adjust a phase setting of the first subwoofer.

The present application provides a control parameter determination method and device based on broadband stability domain modeling of a direct-drive wind turbine, the method comprising calculating the conversion ratio based on the expression of the acquired system's weakest grid-connected strength and the first current inner loop frequency; calculating the current inner loop cutoff frequency based on the conversion ratio and the actual current inner loop cutoff frequency; substituting the current inner loop cutoff frequency into the expression of the second current inner loop frequency to calculate the current inner loop proportional coefficient; the first current inner loop frequency and the second current inner loop frequency are determined based on the transfer function model of the current inner loop control; determining the current inner loop integral constant based on the current inner loop proportional coefficient; determining the voltage outer loop cutoff frequency; substituting the voltage outer loop cutoff frequency into the expression of the open-loop crossover frequency of the voltage outer loop to calculate the voltage outer loop proportional coefficient; and determining the voltage outer loop integral constant based on the voltage outer loop proportional coefficient. This method improves the broadband stability characteristics of direct-drive wind turbines under different grid-connected conditions.

A first subwoofer may be configured to output multimedia content in synchrony with at least one other playback device and a second subwoofer. The first subwoofer may, based on a received indication of an acoustic characteristic of the at least one other playback device, determine a crossover frequency of (i) the first subwoofer and the second subwoofer and (ii) the at least one other playback device. After determining the crossover frequency, the first subwoofer may output a first tone set and a second tone set in synchrony with the second subwoofer and the at least one other playback device, and after outputting the first tone set and the second tone set, receive, from a controller device, an indication of a selected one of the first tone set or the second tone set. Based on the selected tone set, the first subwoofer may adjust a phase setting of the first subwoofer.

The present application relates to multiphase flow metering technical field, specifically disclose a kind of two-phase flow density dynamic compensation method of multi-parameter flowmeter, upstream pressure fluctuation and downstream differential pressure fluctuation are synchronously collected on throttle element by sliding window, to distinguish transmission function with both and extract phase lag angle at crossover frequency;The difference between current phase lag angle and reference value is input as phase shift amount into erosion phase-outflow coefficient correlation model, obtain outflow coefficient decay rate and get real outflow coefficient by sliding weighted average;The real outflow coefficient is substituted into momentum conservation equation, and the cross-sectional gas rate is used as constraint, and the real mixed density is obtained by solving mixed density inverse iteration;Real mixed density is used to calculate mass flow, and the current outflow coefficient and the current phase lag angle are updated as reference value of subsequent window, the present application realizes that density compensation reference is on-line self-migration in erosion state, and compensation effectiveness can be maintained for a long time without shutdown calibration.

A magnetic field sensor architecture is disclosed that provides improved bandwidth and noise performance through the use of three distinct magnetic sensing elements: a spinning Hall- effect sensor for low-frequency and DC sensing, a non-spinning Hall-effect sensor for mid- frequency sensing, and a pickup coil for high-frequency sensing. The sensor combination includes a summing stage comprising frequency-selective filtering elements that process the outputs of the sensing elements to achieve a flat composite frequency response from DC to high frequencies. Two independently selectable crossover frequencies are used to decouple noise optimization from ripple suppression. In some embodiments, the pickup coil and non- spinning Hall-effect sensors are combined and processed through a shared path, with a simplified filter structure.

The embodiment of the invention relates to the technical field of filters, in particular to a filter, a filter filtering method and a storage medium. The filter comprises a PI loop and an auxiliary loop, an example gain coefficient, a first integral gain coefficient and a crossing frequency of the PI loop are determined when the auxiliary loop is closed, and a second integral gain coefficient of the auxiliary loop acting on the PI loop is preliminarily determined based on the crossing frequency and a target noise frequency. And the second integral gain coefficient is adjusted through the output error of the filter, that is, the parameter design of the auxiliary loop acting on the PI loop needs to be participated by the target noise frequency to be filtered, that is, the parameters of the auxiliary loop participating in the filtering are adaptively adjusted based on the target noise frequency to be filtered, and when the target noise frequency is changed, the target noise frequency is changed. In addition, the parameters of the auxiliary loop acting on the PI loop can be adaptively adjusted, so that the filter can be suitable for constant-value systems with different frequency noise interferences, and the stability of the constant-value systems is improved.

The invention discloses a boost circuit system bandwidth optimization method, which comprises the following steps: acquiring an input signal, and outputting an output signal after system signal processing; in the system signal processing process, the duty ratios of the system are detected, and the gain of a compensation loop is modulated under different duty ratios, so that the bandwidth of the system is adjusted; the step of modulating the compensation loop gain comprises the substeps that when it is detected that the duty ratio is gradually increased, the compensation loop gain is increased, so that the system ride-through frequency is improved, the system phase margin is reduced, and the system response speed is increased; and when it is detected that the duty ratio is gradually reduced, the compensation loop gain is reduced, so that the system ride-through frequency is reduced, the system phase margin is increased, and the system stability is improved. The invention further discloses the boost circuit system, and the bandwidth optimization method of the boost circuit system is adopted. The dynamic performance can be optimized while the stability of the system is ensured, and the bandwidth of the system is improved.

The purpose of the present invention is to drive a permanent magnet rotating electrical machine provided with an eddy current suppression member under control conditions capable of suppressing eddy current loss of the entire rotor. A drive system (3) for a permanent magnet rotating electrical machine is provided with: a permanent magnet rotating electrical machine (1) provided with a stator having a stator core and a stator coil (12), and a rotor having a rotor core, a plurality of permanent magnets, and an eddy current suppression member; an inverter (30); and a control device (31) that specifies a carrier frequency that is greater than a cross-loss frequency that is calculated on the basis of mathematical expressions using the dimensions and physical constants of the permanent magnets and the eddy current suppression members.

The invention relates to a playing calibration method of an audio playing system and a related device thereof. The playing calibration method comprises the following steps: acquiring a current frequency division point frequency of the audio playing system; a test audio signal with the current frequency division point frequency as the center frequency is generated, and the test audio signal is sent to the subwoofer and the main loudspeaker box at the same time; performing phase inversion on the audio output signal of the subwoofer to obtain a first audio output signal corresponding to the subwoofer; based on a preset delay adjustment range, performing delay processing on the first audio output signal, and acquiring a target acoustic response signal corresponding to each delay point of the test audio signal in the delay adjustment range through audio acquisition equipment; and calibrating the playing delay between the subwoofer and the main sound box through the target delay. According to the scheme provided by the invention, the delay corresponding to the lowest energy point can be determined by testing the audio signal, so that the playing delay between the subwoofer and the main loudspeaker box is accurately calibrated, the stability and the synchronism of audio playing are ensured, and the auditory experience of a user is improved.

This application discloses a PLC parameter tuning method and system based on online grid impedance identification. It dynamically locks sensitive frequency bands such as LCL resonance and crossover frequency through a key frequency adaptive selection mechanism and tracks grid resonance drift using historical data. Multi-frequency composite disturbance injection and Goertzel parallel demodulation technology are employed to efficiently extract discrete complex impedances at key frequency points. Based on this, the grid model parameters are identified using the least squares method, thereby reconstructing a continuous impedance spectrum across the entire frequency band, effectively overcoming the information loss problem caused by discrete measurements. Combining the reconstructed impedance spectrum with the inverter model, the system open-loop transfer function is constructed to accurately calculate the stability margin, and the proportional and integral gains of the PLC controller are adaptively tuned accordingly. This achieves accurate matching and robust control of complex grid characteristics under limited computing power.

The invention relates to the technical field of microwave signal conditioning, and discloses an up-converter and a microwave signal conditioning method. The up-converter comprises an input port, a channel gating unit, a frequency conversion unit, an output port, a radio frequency local oscillator unit and a control unit. The frequency conversion unit is divided into three channels according to the designed frequency band of the output signal, the three channels have different frequency bands but have cross frequencies, and the range of the cross frequencies is larger than or equal to 1 GHz; the control unit controls the channel gating unit to select a channel for signal transmission according to the frequency of the output signal; when the frequency of the output signal is equal to that of the input signal, the input signal is filtered and amplified by the selected channel to obtain an output signal, and when the frequency of the output signal is greater than that of the input signal, the input signal is filtered, converted and amplified by the selected channel to obtain an output signal. According to the invention, up-conversion and conditioning of microwave signals with limited indexes such as an ultra-wideband frequency band of 30MHz-26.5 GHz, 120dB large dynamic adjustment, 35dB low stray, 0.5 dB / 1GHz high flatness and the like can be realized.

This invention provides a baseline correction method applicable to fault ground motion, comprising the following steps: inputting the earthquake acceleration time history to be corrected and the corresponding GPS measured displacement data; randomly generating an initial population containing time parameters t1 (start time of the strong earthquake segment) and t2 (start time of the last segment of the velocity time history); performing baseline correction on each individual in the population: obtaining the velocity time history by subtracting the mean of the pre-earthquake acceleration based on t1 and integrating; obtaining the displacement time history by fitting the linear trend of the last segment of the velocity based on t2, subtracting the fitted acceleration component, and then integrating twice; using the absolute value of the residual between the corrected displacement end value and the GPS data as the objective function; updating the population through a differential evolution algorithm, wherein the mutation factor and crossover frequency can be dynamically adjusted according to the ground motion velocity time history, displacement residual, and number of iterations to balance global and local searches and avoid invalid solutions; iteratively optimizing until the residual is less than a threshold or the maximum number of iterations is reached; finally outputting the optimal t1, t2, and the corrected displacement time history.

This invention provides a voltage-based converter stability evaluation method, comprising the following steps: S1. Injecting single-phase voltage disturbances of different frequencies into the common coupling point of the converter; S2. Obtaining the line voltage V of the converter under the single-phase voltage disturbance. ab and V bc and the line voltage V on the grid side t,ab S3. Based on line voltage V ab and V bc Determine the positive sequence component V of the converter's response voltage. p Based on line voltage V t,ab and line voltage V bc Determine the positive sequence component V of the grid-side response voltage. t,p S4. Based on positive-order component V t,p With the positive-order component V p S5. Plot a Bode plot of the ratio Vtp / Vp; Find the point in the Bode plot where Vtp / Vp is 0, and determine the crossover frequency f. c The stability of the converter is determined based on the phase corresponding to the crossover frequency.

The invention provides a baseline correction method suitable for fault seismic oscillation. The baseline correction method comprises the following steps: inputting a seismic acceleration time history to be corrected and corresponding GPS actual measurement displacement data; randomly generating an initial population containing time parameters t1 (the starting time of the strong earthquake section) and t2 (the starting time of the end section of the speed time history); performing baseline correction on each population individual: deducting a seismic front section acceleration mean value based on t1 and performing integration to obtain a speed time history, fitting a speed tail section linear trend based on t2, deducting a fitting acceleration component and performing secondary integration to obtain a displacement time history; taking a residual absolute value of the corrected displacement end value and the GPS data as a target function; the population is updated through a differential evolution algorithm, and variation factors and crossover frequency can be dynamically adjusted according to the seismic velocity time history, displacement residual errors and the number of iterations, so that global and local search is balanced, and invalid solutions are avoided; iterative optimization is carried out until the residual error is smaller than a threshold value or the maximum number of iterations is reached; and finally outputting the optimal t1, t2 and the corrected displacement time history.

A method for decoding an encoded audio bitstream in an audio processing system is disclosed. The method includes extracting from the encoded audio bitstream a first waveform-coded signal comprising spectral coefficients corresponding to frequencies up to a first cross-over frequency for a time frame and performing parametric decoding at a second cross-over frequency for the time frame to generate a reconstructed signal. The second cross-over frequency is above the first cross-over frequency and the parametric decoding uses reconstruction parameters derived from the encoded audio bitstream to generate the reconstructed signal. The method also includes extracting from the encoded audio bitstream a second waveform-coded signal comprising spectral coefficients corresponding to a subset of frequencies above the first cross-over frequency for the time frame and interleaving the second waveform-coded signal with the reconstructed signal to produce an interleaved signal for the time frame.

In an example, a system includes a phase locked loop (100) including a charge pump (104) coupled to a phase frequency detector (102), a low pass filter (106) coupled to the charge pump (104), and a VCO (108) coupled to the low pass filter (106), where the charge pump (104) is configured to provide a charge pump current (126) to the low pass filter (106). The system also includes a current source (114) configured to provide a bias current (130) to the charge pump (104). The system includes a first bias compensation circuit (116) configured to increase the bias current (130) in response to a control voltage (128) provided to the VCO (108) being within a first range. The system also includes a second bias compensation circuit (116) configured to reduce the bias current (130) in response to the control voltage (128) provided to the VCO (108) being within a second range.

The invention discloses a metal plate thickness measurement method and system based on electromagnetic eddy current, and the method comprises the steps: building an eddy current detection system, employing a coaxial excitation and reception eddy current sensor, and obtaining the mutual inductance signal change caused by a metal plate in a frequency sweep measurement mode through the eddy current sensor; calculating a characteristic frequency point with equal real part and imaginary part of the mutual inductance signal, and recording the characteristic point as a crossover frequency; respectively adjusting the lift-off distance for n times, and calculating the equal cross frequency of the real part and the imaginary part of the mutual inductance signal again; logarithmic processing is carried out on the n cross frequency points, and the relation between the logarithm of the cross frequency and the lift-off distance is obtained through linear fitting; a large amount of calculation finds that the slope of the fitting straight line is irrelevant to the conductivity, so that additional plate electromagnetic characteristic calibration is not needed, the slope of the fitting straight line is only determined by the thickness of the plate, and effective measurement of the plate thickness can be realized.

In example implementations, an apparatus is provided. The apparatus includes a dielectrophoresis (DEP) separator, an electrical field generator, a tracking system, and a controller. The DEP separator is to separate a plurality of different particles. The electrical field generator is coupled to the DEP separator to apply a frequency to the DEP separator. The tracking system is to track a movement of a type of particles in the DEP separator. The controller is in communication with the electrical field generator to control the frequency and the tracking system to track the separation. The controller is to calculate a cross-over frequency from a cross-over frequency distribution for the type of particles based on a frequency sweep performed on the type of particles and the movement of the type of particles that is tracked.

The invention relates to the technical field of microwave signal conditioning, and discloses a down converter and a microwave signal conditioning method. The down converter comprises an input port, a channel gating unit, a frequency conversion unit, an output port, a radio frequency local oscillator unit and a control unit; the frequency conversion unit is divided into four channels according to the design frequency band of the input signal, the four channels have different frequency bands and have cross frequencies, and the cross frequency range is larger than or equal to 1 GHz; the control unit controls the channel gating unit to select a channel for signal transmission according to the output signal frequency; when the frequency of the output signal is equal to that of the input signal, the input signal is filtered and amplified through the selected channel to obtain an output signal, when the frequency of the output signal is smaller than that of the input signal, a local oscillation signal is generated to the selected channel, and the input signal is filtered, converted and amplified through the selected channel to obtain the output signal. According to the invention, down-conversion and conditioning of microwave signals with limited indexes such as an ultra-wideband frequency band of 30MHz-26.5 GHz, 120dB large dynamic adjustment, 35dB low stray, 0.5 dB / 1GHz high flatness and the like can be realized.