106 results about "Linear phase" patented technology

An example payload for an inspection robot having a mounting rail to inspect an inspection surface, the payload including a wedge element; and a probe holder, including: a mounting rail connection member structured to connect to the mounting rail; a wedge element holder structured to hold the wedge element; a spring-loaded member structured to connect to the mounting rail connection member and to provide a selected vertical force on the wedge element holder; and an extended member structured to connect to the spring-loaded member between a first end and a second end, and to connect to the wedge element holder at the second end.

The invention provides an environment detection method and system based on a sample target detection model. The method comprises the following steps: synchronously acquiring an environment image, a video stream and physical parameters by using a multi-mode sensor; decomposing the data into image features and environmental parameter components through a dual-time sequence control signal, and realizing space-time alignment by adopting a linear phase filter; constructing a foreground region template based on the depth information, and generating target recognition feature representation containing an abnormal blurred target; adversarial training is carried out on the lightweight target detection network in combination with a transfer learning strategy, the network integrates convolutional features and a Transform attention mechanism, and the weight is dynamically adjusted through environmental parameters; fusing a target result and sensor data in real-time detection, and inputting a decision tree model for risk grading; and after the early warning is triggered, reconstructing a false detection sample through an online learning mechanism and iteratively optimizing the model. The system correspondingly comprises a multi-modal data acquisition module, a data enhancement and annotation module, a model training module, a real-time detection and fusion module and an early warning and optimization module. According to the invention, through multi-source data fusion, dynamic data enhancement and an adaptive compensation mechanism, the small target detection precision, the environmental adaptability and the real-time early warning capability are significantly improved.

A dual path PLL provides excellent output phase stability over PVT variations, without implementing a high accuracy TDC. A digital integral path employs a binary phase detector, comparing the reference and feedback signals, and an integrator to generate an oscillator control input to lock the long-term output phase to the reference signal. An analog proportional path employs a linear (e.g., edge triggered) phase detector and a charge pump and filter to generate an oscillator control input to mitigate phase noise in the output signal. The feedback signal to the proportional path is delayed, which has the effect of increasing the width of phase error pulses, and moving the charge pump operating point away from the zero point where it generates both positive and negative currents, which are difficult to match. A second linear phase detector in the proportional path compensates for the increased phase error pulse width by comparing the delayed and non-delayed feedback signals, and generating pulses in the opposite direction.

The invention relates to the technical field of optical detection, and discloses an object surface three-dimensional topography measurement method based on optical interference, which comprises the following steps: acquiring a mixed time domain interference signal sequence in an axial scanning process; extracting seed pixels and constructing a spatial topology connectivity feature matrix; introducing fractional Fourier transform, and constructing a joint decoupling objective function containing a frequency domain nonlinear phase distortion evaluation index and a time domain physical invariant evaluation index; executing multi-stage optimization for the seed pixels, and locking a global optimal rotation angle; array self-adaptive decoupling is executed in combination with the spatial topology connectivity feature matrix, and an optimal rotation angle matrix is generated; and performing signal decoupling and reconstruction on the mixed signal, and extracting the absolute surface height of each pixel point to generate three-dimensional shape data. According to the invention, through multi-dimensional joint decoupling and spatial prior constraint, the problem of phase decoupling caused by film interference aliasing is solved, and the calculation overhead of a large-pixel array is reduced while the measurement precision is improved.

The invention relates to a phased array tracking method based on four-dimensional joint weighted dynamic pre-switching, and belongs to the technical field of phased array communication. The method comprises the following steps: updating space-time correlation parameters to a target historical motion track database, and generating a target state prediction value based on a UKF prediction method; starting a four-dimensional joint gradient weighting program, carrying out linear phase interpolation of a time delay dimension, and generating a control signal with a continuous phase; solving a mutual coupling matrix, establishing a cross-array-plane phase mapping model based on cubic spline interpolation, and compensating a residual phase error; according to the real-time radar cross section, the number of effective array elements participating in beam forming is dynamically adjusted, a final beam pointing signal is generated, and stable relay tracking of the current period is completed. The method solves the problems of phase jump and signal attenuation during multi-array-plane switching, and is suitable for continuous tracking in a high-speed moving scene of the unmanned aerial vehicle.

The invention discloses a distributed driving vehicle fault-tolerant driving control method considering motor torque time lag, and belongs to the technical field of vehicle system active safety control. According to the method, firstly, an FIR filter with a linear phase characteristic is utilized to characterize a wheel torque time lag tau; estimating the time lag of each wheel torque in real time by adopting a gradient descent method to obtain a time lag estimated value # imgabs0 # obtained in real time, and designing a fault-tolerant driving control strategy according to the estimated value of the wheel torque time lag; and designing a Smith predictor according to different driving modes in the designed fault-tolerant driving control strategy to realize compensation of time delay. The method is based on the FIR filter, can be efficiently realized in hardware, and is good in stability and strong in noise suppression capability.

The application discloses a loudspeaker phase equalization signal processing system and a pole parameter determination method thereof, which equalizes the loudspeaker phase response in a set equalization frequency range to linear phase, and the system comprises a phase controller and a group delay equalizer in cascade; the phase controller is a first-order IIR all-pass filter; the group delay equalizer comprises S low-order IIR all-pass filters in cascade, wherein the first N1 low-order IIR all-pass filters are low-order causal IIR all-pass filters, and the last N2 low-order IIR all-pass filters are low-order non-causal IIR all-pass filters. The application can equalize the loudspeaker phase through the all-pass filter with low operation complexity and parameters, can significantly reduce the calculation amount required by low-frequency phase equalization, can improve the linear degree of the loudspeaker phase response, and can improve the sound quality and listening experience.

An example payload for an inspection robot having a mounting rail to inspect an inspection surface, the payload including a wedge element; and a probe holder, including: a mounting rail connection member structured to connect to the mounting rail; a wedge element holder structured to hold the wedge element; a spring-loaded member structured to connect to the mounting rail connection member and to provide a selected vertical force on the wedge element holder; and an extended member structured to connect to the spring-loaded member between a first end and a second end, and to connect to the wedge element holder at the second end.

The invention relates to the technical field of broadband signal synthesis and high-speed digital-to-analog conversion, in particular to an oversampling-based real-time frequency interleaving digital-to-analog conversion system aliasing suppression method and system, and aims to solve the problem of spectrum aliasing caused by non-ideal characteristics of a digital sub-band decomposition filter and an analog filter under a real-time architecture of the system. In the invention, the sub-band decomposition is completed by adopting the linear phase complementary filter bank, so that distortion introduced by a transition band of a digital filter is avoided; by restraining system parameters such as passband and stopband frequencies and local oscillation frequency of a sub-band decomposition filter, a protection band is set by an oversampling mechanism, a frequency margin is reserved for a transition band of the filter, and aliasing components are suppressed. According to the method, extraction aliasing of a digital domain and mirror image aliasing of an analog domain are avoided at the same time from the system architecture, the frequency spectrum purity of output signals is improved, the method is suitable for a real-time system for processing continuous data streams, and technical support is provided for achieving a high-performance broadband signal source.

The invention discloses a method and a system for optimizing a metering front end of an intelligent electric meter. The method comprises the following steps of: setting an anti-aliasing network with a near-linear phase at the front end of a metering channel and synchronously sampling; determining a range switching window based on zero crossing or a preset voltage change rate, executing automatic range switching in the window, and performing overlapping sampling and digital splicing on samples before and after switching; determining a rectification conduction empty window based on the rectification conduction prediction, suspending sampling in the empty window, and compensating a missing sample; injecting a reference signal into the channel at the calibration injection window, obtaining a correction coefficient according to response, and performing online correction; the three types of windows are not overlapped and are uniformly scheduled by a synchronous time sequence; and completing power and energy calculation according to the corrected voltage and current sequence. The system comprises an anti-aliasing network unit, a range control unit, a rectification conduction detection unit, an air window door control unit, an injection and online correction unit, a time sequence synchronization unit, a metering calculation unit and the like. According to the invention, low-distortion, wide-range and consistent metering output can be realized in practical application.

The invention provides a rotor wing shielding compensation method for helicopter satellite communication, and relates to the technical field of helicopter communication methods, and the method comprises the following steps: collecting angular velocity data in real time through a rotor wing main shaft sensor, constructing a rotating speed state equation, and providing accurate input for phase prediction; predicting a rotor phase based on an extended Kalman filter; a dynamic time slot distribution function is designed, so that the communication time slot length is automatically adjusted along with the rotation speed change of the rotor; a non-linear phase error caused by rotor vibration is counteracted through a feed-forward compensation item; closed-loop time calibration of a communication protocol and a mechanical system is realized by adopting double PID controllers. According to the method, real-time closed-loop synchronization of a mechanical system and a communication protocol is realized by establishing a three-dimensional mapping relation of rotor rotating speed-phase-communication time slot, so that the problem of nonlinear error accumulation during dynamic change of the rotating speed is solved.

The invention discloses an SAR image self-focusing distortion correction method and device, and belongs to the technical field of synthetic aperture radars. The method comprises the following steps: carrying out distance blocking and orientation sub-aperture division on a defocused SAR image, selecting a sample, and carrying out orientation decompression to a phase historical domain; performing azimuth dechirp processing on the sub-aperture data in each distance sub-block, and estimating a phase error through a standard PGA algorithm; after splicing sub-aperture phase errors and removing an overall linear phase, performing phase compensation and azimuth compression to obtain a focused image; and for azimuth distortion caused by residual linear phase of the compensated image, extracting a phase error linear term coefficient through a sliding window, deducing an azimuth shift distance in combination with Fourier transform time shift characteristics, and finally performing shift correction by adopting sinc interpolation. According to the method, the image focusing quality is improved, and meanwhile, the ground feature continuity and the image resolution are kept.

In some implementations, a phase detector to enable coherent beam combining includes a first half-waveplate may rotate a polarization of a first input beam and a second input beam to 45 degrees. A first birefringent window may divide the input beams into beamlet pairs associated with orthogonal polarizations, and a second birefringent window may shift the first beamlet pair and the second beamlet pair such that a first beamlet of the first beamlet pair and a second beamlet of the second beamlet pair form overlapping beams after the orthogonal polarizations and reversed by a second half-waveplate. An analyzer may then split the overlapping beams into a first output beam associated with a first intensity and a second output beam associated with a second intensity, where a difference between the first and second intensity is related to a phase difference between the first input beam and the second input beam.

The present invention relates to a distributed vibration sensing method based on Pearson correlation coefficient optical frequency domain reflection, comprising the following steps: a first step of measuring a reference signal and a measurement signal; a second step of compensating for nonlinear phase noise and calculating a Rayleigh backscattering spectrum; a third step of obtaining a local RBS in the optical frequency domain; a fourth step of calculating a distributed Pearson correlation coefficient (PCC); based on the principle that vibration will cause a step-like jump in the distributed Pearson correlation coefficient (PCC), and that the size of the jump is proportional to the vibration amplitude within a certain range, the PCC of the local reference RBS and the local measurement RBS in each window is calculated to obtain the distributed PCC of the reference signal and the measurement signal at various positions of the optical fiber to be measured; a fifth step of detecting a change point in the PCC using a pruned exact linear time (PELT) algorithm based on dynamic programming to determine a possible vibration position; a sixth step of determining the vibration position; and a seventh step of determining the vibration amplitude based on the differential PCC.

This system is directed to an orbital angular momentum generator which can include an AOD; a beam shaping optic assembly; a log-polar optic; a Fourier lens; and, wherein the orbital angular momentum generator is configured to produce pulse shaping according to the application of a quadratic waveform chirp that corresponds to one or more OAM modes. The system can include an ultrashort pulsed laser; a log-spiral transformation assembly; an AOD; an ellipse generator; a λ / 2 plate; and, wherein the optical system is configured to provide for multiple coherent spiral beams with control of amplitude and relative phase. The system can include an ultraviolet orbital angular momentum generator comprising: a femtosecond pulsed laser; a crystal configured to provide a collinear phase-matching; and can provide a UV OAM source for imaging with high resolution and quantum information. The AOD can be replaced with a scanning mirror and configured to add a linear phase gradient.

The invention discloses a TCN-based vehicle-mounted sound equipment equalizer compensation method and system, and relates to the technical field of vehicle-mounted electronic equipment, and the method comprises the steps: playing a test signal in a vehicle-mounted environment, collecting a distorted time domain waveform affected by an acoustic environment in a vehicle through a microphone, and carrying out the preprocessing of the distorted time domain waveform; inputting the processed waveform into a time convolution network, extracting multi-scale time sequence features, and predicting to obtain a first half segment coefficient of a linear phase FIR filter after global average pooling and full connection layer mapping; carrying out symmetrical overturning splicing on the front half segment coefficient, constructing a complete linear phase FIR filter coefficient, and carrying out direct current gain normalization processing; and finally, carrying out one-dimensional convolution operation on the normalized FIR filter coefficient and an original audio signal, and outputting an equalized audio signal subjected to frequency response compensation. According to the invention, the adaptive equalization compensation of the vehicle-mounted audio system is realized, and the tone quality performance and the hearing experience are remarkably improved while the linear phase characteristic is ensured.

The application belongs to the field of transformers, and discloses a linear phase-shifting transformer equivalent circuit modeling and performance parameter obtaining method, analyzes the electromagnetic relationship between the primary side winding and the air gap when the linear phase-shifting transformer is in steady-state operation, and Maxwell equations of the linear phase-shifting transformer; based on the theory of one-dimensional field, the equivalent circuit of the linear phase-shifting transformer is established and solved when the longitudinal edge effect is considered. The performance parameter obtaining method is also disclosed, which comprises: solving the established equivalent circuit model to obtain the resistance and leakage reactance of the primary side winding, the excitation reactance, and the secondary side winding resistance; and calculating the performance parameters of the linear phase-shifting transformer based on the equivalent circuit solving result. The application considers the actual situation of the transformer in electromagnetic analysis, the model is more accurate, the calculation precision is high, the winding loss, efficiency and voltage regulation rate and other performance parameters of the transformer can be quickly and effectively calculated, the application is relatively convenient in actual calculation and analysis, and has high practical value.

The application provides an estimation method and device of a seismic wavelet, which comprises the following steps: constructing a Ricker wavelet with the same main frequency as the obtained observation data; obtaining seismic wave forward simulation shot gather prediction data through forward simulation of the Ricker wavelet; filtering the Ricker wavelet based on the observation data and the seismic wave forward simulation shot gather prediction data; constructing a smooth spectrum linear phase short wavelet based on the spectrum characteristics of the filtered wavelet; intercepting the waveform of the smooth spectrum linear phase short wavelet in the main energy interval in the filtered wavelet and performing smoothing processing; calculating the phase spectrum corresponding to the waveform after the smoothing processing, and constructing a target wavelet based on the phase spectrum and the smooth spectrum linear phase short wavelet. Thus, the resolution and accuracy of the subsequent processing result are improved, and the problem that conventional land data is difficult to stably estimate a high-precision and high-resolution wavelet is solved.

The invention relates to the technical field of single-pixel calculation imaging, in particular to a self-adaptive sampling dynamic target tracking method and device based on single-pixel imaging, and can solve the problem of limitation of a traditional fixed sampling mode in efficiency and quality to a certain extent. The self-adaptive sampling dynamic target tracking method based on single-pixel imaging comprises the following steps: generating four groups of sine and cosine coding illumination patterns with different phase characteristics; circularly projecting the illumination pattern to a target scene through a spatial light modulator to obtain a modulation signal; receiving a modulated reflected light signal of a target scene based on a photoelectric detector, converting the light signal into an electric signal, and receiving the electric signal by a data acquisition card; dynamically adjusting the sampling frequency by adopting a self-adaptive sampling strategy, and controlling the maximum and minimum sampling times based on a voltage difference threshold value; target displacement is calculated by using Fourier linear phase shift characteristics, static background interference is eliminated in combination with a background frame difference method, and real-time tracking of a dynamic target is realized.

The present invention relates to a phased array tracking method based on four-dimensional joint weighted dynamic pre-switching, and belongs to the field of phased array communication technology. The present invention includes: updating the spatiotemporal correlation parameters to the target historical motion trajectory database, generating the target state prediction value based on the UKF prediction method; starting the four-dimensional joint gradual weighting program, performing linear phase interpolation in the time delay dimension, and generating a phase-continuous control signal; solving the mutual coupling matrix, establishing a cross-array phase mapping model based on cubic spline interpolation, and compensating for the residual phase error; dynamically adjusting the number of effective array elements participating in beam synthesis according to the real-time radar scattering cross section, generating the final beam pointing signal, and completing the stable relay tracking of the current cycle. The present invention solves the problems of phase jump and signal attenuation during multi-array switching, and is suitable for continuous tracking of UAVs in high-speed moving scenarios.

The application relates to the field of backscatter technology and discloses a single-receiver WiFi backscatter communication method and system, which comprises the following steps: a tag receives OFDM symbols from ambient WiFi signals, a linear phase factor corresponding to a tag-related cyclic shift value is applied to only the middle part of a data load, and the OFDM symbols of a reflection signal are reconstructed based on the middle part of the modulated data load; a receiver extracts the modulated part from the received OFDM symbols of the reflection signal, performs frequency domain inverse shift compensation on each candidate cyclic shift value, obtains a reconstructed data load based on the obtained compensated spectrum, calculates the correlation score between the power spectrum of the reconstructed data load each time and a binary template predefined based on the position of the empty subcarrier, decodes the cyclic shift value, and recovers the corresponding tag data. The application can realize a high data throughput without sacrificing OFDM compatibility.

The invention relates to a real-time digital audio filtering system and an implementation method thereof. The real-time digital audio filtering system is composed of a high cut-off filter bank module, a low cut-off filter bank module, a subtracter module, a sampling rate synchronous interpolator module and a sampling rate converter module. Wherein the high cut-off filter bank and the low cut-off filter bank are respectively composed of a plurality of stages of low-pass filtering units, and each stage of low-pass filtering unit is composed of a plurality of FIR low-pass filters; and the sampling rate synchronous interpolator is used for synchronizing the frequencies of the output signals of the high and low cut-off filter banks. Different bandwidth requirements can be met only by designing a small number of low-pass filters, and bandwidth adjustment is flexible and convenient; the used filters are low-order FIR (Finite Impulse Response) filters, so that the time delay of the system is less, the operand is small, the output signal is linear phase and has no distortion, and meanwhile, the method also has good universality and can be applied to other real-time digital audio systems after the cut-off frequency of the filters is simply adjusted.

Embodiments of the present invention relate to a transmitting device (100) for transmitting an OFDM signal (510) in a communication system (500). The OFDM signal (510) is obtained by spreading a sequence of Nbit bits to obtain Nsymb modulation symbols by multiplying each bit of the sequence of Nbit bits by a corresponding spreading sequence of a sequence of Nbit spreading sequences. Each spreading sequence of the sequence of the Nbit spreading sequences is a linear phase sequence having a constant rotational phase angle [phi]. And the Nsymb modulation symbols are multiplied by a discrete Fourier transform precoder, so that Nsymb Fourier coefficients can be obtained. Finally, the OFDM signal (510) is transmitted, the OFDM signal (510) comprising the Nsymb number of Fourier coefficients mapped onto the K number of OFDM subcarriers. The invention further relates to a corresponding method and to a computer program.

A method for reducing inter symbol interference (ISI) and inter carrier interference (ICI) in transmissions between a sender and a recipient within a wireless communication network. For at least one multicarrier symbol comprising a first subcarrier modulated with an original reference signal and multiplexed with a second subcarrier modulated with an original payload signal. The method includes applying a multiple symbol shift configuration on at least a second multicarrier symbol adjacent to the first multicarrier symbol by repeating the original reference signal and the original payload signal in the second multicarrier symbol on respective subcarriers and applying a linear phase shift to each repeated reference signal and payload signal. The same linear phase shift is used for both the repeated reference signal and the repeated payload signal.

The invention discloses a broadband achromatic programmable electromagnetic camouflage device based on a fluid access metasurface. The broadband achromatic programmable electromagnetic camouflage device comprises the fluid access metasurface composed of a plurality of periodically arranged super units. Each super unit comprises a plurality of units arranged in a matrix; each unit comprises a microfluid channel layer and a solid metal layer, and the microfluid channel layer is located above the solid metal layer; the microfluid channel layer is connected to an external driving system through the injection and discharge port, and the external driving system is used for injecting liquid metal or dielectric liquid into the microfluid channel layer; when the microfluid channel layer is filled with liquid metal, the unit is in a first working state; and when the micro-fluid channel layer is filled with the dielectric liquid, the unit is in a second working state. According to the invention, linear phase dispersion control can be realized in a broadband, and it is ensured that the generated false target echo keeps high fidelity in a time domain when facing a broadband pulse radar.

This invention relates to the field of signal processing technology and provides a ground clutter frequency domain suppression method based on correlation spectrum. Its key feature is the use of phase information from the autocorrelation spectral density of weather radar echo signals to identify and suppress ground clutter signals. The method includes: adaptively selecting an optimal data window function based on the clutter-to-noise ratio of the weather radar echo signal and performing power-preserving processing; calculating the autocorrelation spectral density and power spectral density, and effectively distinguishing clutter from broadband weather signals using the local deviation characteristics of the autocorrelation spectral density relative to the ideal linear phase, thereby performing clutter identification and filtering. Based on the autocorrelation spectral density after filtering out ground clutter, an inverse transform is performed to calculate the autocorrelation function, completing the time-domain estimation of the weather radar detection variables. This invention effectively solves the problem that traditional ground clutter suppression methods cannot accurately identify and eliminate ground clutter mixed in with weather signals.

The application belongs to the technical field of radio frequency communication, and discloses a novel wideband linear phase filter and a design method thereof. The novel wideband linear phase filter comprises a first port, a second port, and three first transmission lines connected in series between the first port and the second port. Four connection points are formed between the first port and the adjacent first transmission line, between the three first transmission lines, and between the second port and the adjacent first transmission line. Four short-circuit branch lines are connected at the four connection points one by one. An inductance circuit module is connected at one end of the connection point between the first port and the adjacent first transmission line, and connected at the other end of the connection point between the second port and the adjacent first transmission line.

The application discloses a kind of cross-scale visual ultra-precision motion measurement device and method, the device includes image sensor, aperture diaphragm, imaging lens group, coaxial light source, beam splitter, positioning platform, encoding plate and DSP and ARM integrated signal processing system.In the method, by selecting the number of linear feedback shift register and period large λ and carrying out periodic coding, after DSP and ARM signal processing system pre-processing operation to image, static random access memory is driven to carry out image caching;Two-dimensional Fourier transform is executed to cached image, and relevant linear phase processing is carried out;According to the phase data obtained by linear phase processing, the corresponding binary sequence on local image is identified;The identified local binary sequence is looked up to the binary sequence of encoding plate and positioned, and according to the phase constant of periodic phase measurement, fine positioning is carried out.

The invention discloses a radio frequency fingerprint extraction method and device, electronic equipment and a storage medium. The radio frequency fingerprint extraction method comprises the following steps: sampling a received signal, and carrying out down-conversion to obtain a baseband signal; frame synchronization is carried out on the baseband signal, carrier frequency offset compensation and phase offset compensation are carried out on the signal after frame synchronization, and a target signal is obtained; converting the target signal to a frequency domain to obtain a frequency domain representation; and according to the frequency domain representation of the target signal, a phase curvature feature is extracted as a radio frequency fingerprint, and the phase curvature feature is a second-order difference of phases between adjacent frequency points. According to the method, linear phase distortion introduced by channels can be effectively eliminated, and only nonlinear phase response caused by transmitter hardware distortion is reserved, so that robust radio frequency fingerprint extraction is realized under various channel conditions, and reliable support is provided for high-precision physical layer identity authentication.

This invention discloses a millimeter-wave wide-beam DRA, a wide-angle beam scanning phased array, and their design methods. The DRA consists of a DR and a microstrip coupling slot located directly below the DR. This invention enables the non-exciteable DRA to achieve TE by setting the dimensions of the slot and the DR. 112 The resonant frequency of the mode is close to that of the slot operating mode, and the field inside the DR will exhibit a similar behavior to that of the TE mode. 112 The field distribution of the mode forms an equivalent magnetic current parallel to the ground plane, thereby achieving wide beam characteristics in the E-plane and H-plane; moreover, arranging multiple such small-sized DRA units at equal intervals can form a linear phased array in the E-plane (H-plane), whose beam can be scanned from -72° to +72° (-65° to +65°), with a gain ripple of 2.5dB (0.5dB), and the present invention does not require any parasitic structures or additional active control circuits.