80 results about "Linear phase" patented technology

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 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 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.

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 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.

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.

The present invention discloses a nonlinear component for wavefront control based on a graphene nonlinear metasurface. The nonlinear component comprises a plurality of periodically distributed metagratings, each comprising a metal substrate provided with a plurality of periodically distributed grooves filled with a dielectric layer, and the dielectric layer covered with periodically distributed graphene ribbons. Independent voltages are applied to the graphene ribbons to control their chemical potential, thereby achieving a nonlinear phase gradient. In the terahertz domain, the present invention provides an improved diffraction law for nonlinear wavefront control based on a graphene nonlinear phase gradient metasurface. This law can overcome the limitations of NGSL for nonlinear wavefront control. By rationally adjusting the chemical potential of graphene through applied voltage, multifunctional control of nonlinear waves, including reflection and beam steering, is achieved, thereby enabling the design of nonlinear components.

The invention discloses an anti-symmetric filter design method based on an anti-auto-inverse matrix theory, and belongs to the technical field of digital signal processing. According to the method, a design problem of an antisymmetric filter is modeled into an optimization problem of an impulse response vector h, and an inverse self-inverse constraint h =-Jh (J is an inverse unit matrix) is applied, so that an optimization target minize | A -d | is constructed. An iterative solution technology of a generalized coupling Sylster transpose matrix equation is adopted, and through parameter initialization, residual matrix updating, step length dynamic adjustment and anti-auto-back projection operation, it is ensured that a filter coefficient strictly meets antisymmetry. Furthermore, the calculation complexity is reduced by using block calculation, fast multiplication and a precondition technology, and the frequency domain performance is optimized in combination with a weighted least square method and a Lagrange multiplier method. According to the filter designed by the invention, the strict linear phase characteristic is maintained, meanwhile, the stop-band attenuation can reach more than 50dB, the gradient of a transition band is improved by 30%, and the group delay fluctuation is controlled within 0.1 sampling point, so that the filter is suitable for medical image and radar signal processing and high-fidelity audio systems, and has the characteristics of high calculation efficiency and excellent performance.

The application relates to a digital wave trap, a digital low-pass filter and a design method, a medium and an electronic device. The digital wave trap comprises a wave limit boundary anchoring unit and a wave limit zero point modulation unit which are cascaded in sequence, the wave limit boundary anchoring unit adopts a cascaded integral comb filter structure and is used for generating a first attenuation zero point at a boundary frequency of a target wave trap frequency band; the wave limit zero point modulation unit adopts a finite-length unit impulse response filter structure and is used for generating at least one second attenuation zero point in the target wave trap frequency band; and a continuous suppression band for the target wave trap frequency band is formed in the amplitude-frequency response of an output signal of the wave limit zero point modulation unit by the first attenuation zero point and the at least one second attenuation zero point. By using the digital wave trap provided by the application, a digital low-pass filter which can deeply and widely suppress power frequency interference and maintain strict linear phase and excellent low-pass characteristics can be designed without significantly increasing hardware resources and power consumption.

A phase interpolator circuit includes a capacitance circuit, a switched resistor network, and interpolation management circuitry. The resistor network receives a start-phase signal and an end-phase signal, and generates an interpolated output signal from a voltage on the capacitance circuit. The interpolation management circuitry receives an interpolation code defining an intermediate phase between the start-phase signal and the end-phase signal, charges or discharges the capacitance circuit through the resistor network, and controls the resistor network to set a phase of the interpolated output signal to be the intermediate phase. The interpolation management circuitry also (i) responsively to a transition in the start-phase signal, sets the resistance of the resistor network based on the interpolation code, and (ii) responsively to a voltage level on the capacitance circuit, sets the resistance of the resistor network to a constant resistance, and flows through the capacitance circuit an additional boosting current.

The present application relates to the technical field of thickness measurement, and discloses a linear dimensional measurement method for AR module thickness, comprising: obtaining a spectral interference signal and resampling to a wave number space to generate a wave number domain complex sequence; extracting a real part, an imaginary part and a first derivative term of the wave number domain complex sequence; establishing an orthogonal component set; extracting a transient phase slope by using differential mapping between the orthogonal components; determining a wave number domain group delay distribution; calling a dispersion calibration matrix to correct nonlinear deviation; converting nonlinear phase evolution into linear phase gradient; fitting the linear phase gradient to solve a physical thickness value; and bypassing arctangent calculation and phase unwrapping by establishing phase gradient mapping logic, suppressing phase jump caused by interference envelope aliasing from the dimension of physical energy distribution, improving thickness calculation stability of an extremely thin medium layer under environmental interference, and realizing physical decoupling of material dispersion characteristics and geometric dimensional parameters.

Method and system method comprising encoding a source word to be transmitted in a data unit from a source station in a wireless network, generating a first OFDM symbol that carries a data segment corresponding to encoded bits of the source word, duplicating the first OFDM symbol to generate a second OFDM symbol that is a linear phase-rotated copy of the first OFDM symbol; and transmitting the data unit including the first OFDM symbol and the second OFDM symbol.

This invention relates to a method for enhancing virtual shot signals from a small number of seismic sources based on a convolutional neural network (CNN). The CNN identifies and suppresses coherent noise and spurious phase axes in seismic data. Virtual shot records with a small number of passive seismic sources are used as training data, while those with a larger number of sources are used as training labels. The characteristics of the effective signal are learned from these labels to suppress coherent noise and spurious phase axes, and to restore waveforms in areas of discontinuity. For virtual shot records with uneven source distribution, those with a wider distribution are used as labels. In this case, the network's task is not only to suppress coherent noise and spurious phase axes and restore waveform continuity and extension, but also to restore intersecting linear phase axes to hyperbolic phase axes. This reduces the impact of passive source acquisition on seismic records, ultimately achieving better results and improving the applicability of passive source seismic exploration.

An orthogonal frequency-division multiplexing (OFDM) signal is obtained by spreading a sequence of Nbit number of bits to obtain Nsymb number of modulation symbols based on multiplying each bit in the sequence of Nbit number of bits with a corresponding spreading sequence in a sequence of Nbit number of spreading sequences. Each spreading sequence in the sequence of Nbit number of spreading sequences is a linear phase sequence having a constant rotational phase angle Φ. The Nsymb number of modulation symbols are multiplied with a discrete Fourier transform precoder to obtain Nsymb number of Fourier coefficients. The OFDM signal including the Nsymb number of Fourier coefficients mapped onto K number of OFDM subcarriers is transmitted.

The invention relates to the technical field of radar signal processing, in particular to a ground-based MIMO SAR amplitude-phase error correction method and device and a storage medium, and the method mainly comprises the steps: correcting an original echo signal of two-dimensional echo data according to a compensation matrix, and obtaining initial correction data; eliminating invalid distance units of the initial correction data based on a preset energy threshold value, selecting and sorting the remaining units according to the calculated signal-to-clutter ratio and normalized amplitude variance, eliminating linear phase offset of the distance units, aligning the strongest scattering point to the center, iteratively rotating the initial phases of the distance units to enable the directions of the initial phases to be consistent, and obtaining the initial correction data of the distance units. Obtaining first processing data; and estimating a channel phase error through a weighted least square method based on the unwrapped phase and the phase noise variance obtained by each iteration. According to the invention, the problems of poor adaptability to complex scenes and low correction precision in the prior art can be solved, and millimeter-level precision is realized.