263 results about "Pulse repetition frequency" patented technology

The invention discloses a laser coaxial beam combining system for improving the repetition frequency of laser pulses, which comprises p polarization pulse lasers, a pulse time sequence controller and n stages of beam combining devices, each stage of beam combining device comprises an s polarization pulse laser, a polarization beam combiner and an electro-optical Q switch, and n is a non-negative integer and is greater than or equal to 1. The invention has the following advantages: a plurality of beams of laser in different polarization states can be combined, the pulse repetition frequency and the output average power of the laser are improved, the optimal pulse energy and peak power are maintained, and coaxial output of pulses in the same polarization state is realized.

The invention relates to a semiconductor wafer generation method, which comprises the following steps of: firstly, setting laser scanning times, and then respectively setting a scanning path and a dot spacing of each laser scanning; determining a laser scanning speed and a laser pulse repetition frequency based on a calculation rule preset for each laser scanning, and determining a corresponding modified point diameter, laser pulse energy and an offset distance of a laser focus relative to a preset stripping surface; the pulse laser is focused on a preset stripping surface in the crystal ingot or below the preset stripping surface, and n times of laser scanning are carried out, so that modified points and cracks are sequentially formed on the preset stripping surface; and stripping the crystal ingot along the preset stripping surface to obtain a wafer and a residual crystal ingot. The method not only can eliminate burrs at the edge of the wafer, but also can further reduce the material loss of laser stripping, and has the advantages of simple process conditions, good modified layer morphology, low wafer stripping difficulty and suitability for large-scale industrial application.

The invention provides a single photon pulse laser radar target detection method and system. The method comprises the following steps: modulating pulse emission time delay by adopting a pseudo-random number function to obtain a pulse laser emission time sequence; a precise time-to-digital converter is adopted to collect output signals of the single-photon detector, the arrival time of photons is recorded, and an echo photon time sequence is obtained; the method comprises the following steps: intercepting echo photon time subsequences in a pulse laser emission time sequence according to a fixed length sequence, delaying the echo photon time subsequences in combination with an echo photon time sequence delay amount to obtain a delay subsequence, and carrying out matching counting on the delay subsequence and the echo photon time sequence to obtain a matching counting number; continuously adjusting delay to obtain a matching function; and performing threshold detection on the matching function, and calculating a target distance by taking an echo photon time subsequence delay amount corresponding to the threshold detection as pulse round-trip flight time. According to the invention, the problem of fixed pulse repetition frequency ranging ambiguity is solved.

The present invention discloses a method for SAR satellite high-resolution imaging mission planning. Considering the satellite resource constraints and the imaging mission requirements of high resolution comprehensively, mission planning is carried out in two aspects of attitude maneuver and timing, planning multiple imaging missions at one time, improving the utilization efficiency of satellite resources and the observation speed of the satellite, and being able to meet the imaging mission requirements and achieve the required resolution and swath width indicators; the present invention avoids conflicts between attitude switching, power-on / off times, and storage timing among imaging missions, and completes imaging missions in order from high to low according to the priority. The present invention uses the least squares method to fit the attitude Euler angle curve, and takes the derivative to obtain the attitude Euler angular velocity and the attitude Euler angular acceleration, improving the calculation accuracy. When calculating the timing parameters, the present invention uses simulation to verify whether the segmented variable pulse repetition frequency design result can ensure the effective reception of echoes, ensuring the accuracy of the timing parameters.

A method of simulating radar ground or sea clutter for testing and designing of radar by providing a terrain model including discrete flat ground patches each having a reflectivity, area, surface normal vector, and position within a global coordinate frame, calculating triplet values of reflected energy, range and Doppler shift for each discrete patch of the terrain model for a given position and pose of an antenna with known gain and phase characteristics within the global coordinate frame; and for a given radar receiver sample rate and Pulse repetition frequency (PRF), resampling and integrating over all patches through carrying out a 2D transformation using a non-uniform Fast Fourier Transform. The method can correct the lack of spatial correlation and increase the speed at which realistic ground clutter modelling can be generated.

The invention provides an inter-satellite direct wave interference suppression method and system for synthetic aperture radar satellites. The method comprises the following steps: inputting SAR original echo data and system parameters thereof; calculating a pulse repetition frequency, a signal bandwidth and a frequency modulation rate; performing matched filtering and filtering on the original echo data to obtain an echo signal; and carrying out direct wave interference trapped wave processing and inverse matching filtering processing on the echo signal, and outputting original echo data after suppression processing. According to the method, signal self-correlation processing is adopted for detecting and suppressing the inter-satellite direct wave interference for the first time, the problem that an existing inter-satellite direct wave interference suppression processing method greatly depends on model applicability is solved, and important technical support is provided for subsequent large-scale SAR constellation earth imaging observation; direct wave interference is suppressed through a parameterization method, and the application effect of the SAR satellite in the fields of resource investigation, topographic mapping, disaster monitoring and the like is remarkably improved.

The invention relates to a high squint SAR imaging processing method under Doppler frequency distance time varying. The method comprises the following steps: firstly, carrying out linear walking correction and distance compression according to a squint angle; then distance partitioning and azimuth upsampling are carried out according to the pulse repetition frequency, the instantaneous Doppler bandwidth and the Doppler frequency time-varying quantity along with the distance, azimuth spectrum ambiguity caused by the change of the Doppler center frequency along with the slope distance is eliminated through azimuth spectrum extension, and sub-block splicing is carried out after upsampling of all sub-blocks is completed; carrying out azimuth space-variant resampling in a two-dimensional frequency domain, and eliminating azimuth space-variant in a range gate; then consistent compression and stot interpolation are carried out, and two-dimensional accurate focusing is completed; and finally, correcting image distance position time shift caused by linear walking correction, and intercepting an effective imaging area to obtain a focused SAR image. According to the method, the Doppler spectrum fuzzy problem caused by Doppler frequency distance time variation can be effectively eliminated, so that effective application of a traditional large squint algorithm is ensured, and a correctly focused SAR image is obtained.

The invention discloses a radar working mode recognition method based on a pulse description graph and comparative learning, and the method comprises the steps: obtaining a radar pulse sequence which comprises a plurality of pulse description words arranged according to a time sequence; performing pulse waveform parameter feature transformation on the pulse description words in the radar pulse sequence to obtain a pulse waveform parameter feature sequence; performing pulse repetition frequency mode feature transformation on the pulse description words in the radar pulse sequence to obtain a pulse repetition frequency mode feature sequence; adding the pulse waveform parameter feature sequence and the pulse repetition frequency mode feature sequence to obtain a label-free pulse description graph; performing bilinear interpolation and normalization processing on the unlabeled pulse description graph to obtain a processed unlabeled pulse description graph; and inputting the processed label-free pulse description graph into the trained working mode recognition model for processing to obtain the predicted current working mode of the radar. According to the invention, many radar working modes can be identified and the identification accuracy is high.

The invention discloses a time domain azimuth wide bunching imaging method based on sub-pulse diversity, and the method comprises the steps: constructing a multi-frequency sub-pulse wide bunching signal model, enabling different sub-pulse beams of a radar to point to different imaging regions, and obtaining a total echo signal received by the radar; according to the characteristics of a radar system, the pulse repetition frequency and synthetic aperture time of the radar are designed; and based on the pulse repetition frequency and synthetic aperture time of the radar, performing wide-range bunching imaging processing on the total echo signal received by the radar to obtain a complete image with large azimuth imaging breadth. According to the invention, the single pulse of the radar is divided into a plurality of sub-pulses, and the different sub-pulses point to different azimuth positions, so that the radar has the azimuth wide bunching capability; the application of a sub-pulse diversity technology in an imaging system is effectively realized, and the problems of high operation complexity and distance resolution loss of a scene edge part of a method for applying a frequency scanning radar to an azimuth array are solved.

The invention discloses a method, a system and a device for realizing high-repetition-frequency wide-width imaging, and relates to the technical field of high-repetition-frequency wide-width imaging, and the method comprises the steps: carrying out the pulse compression of large-size imaging echo data; setting the number of accumulation frame periods and the number of imaging areas; a first cache, a second cache, a first processing core and a second processing core are arranged, high repetition frequency imaging accumulation is conducted on pulse pressure data of multiple accumulation frame periods through the first cache, the second cache, the first processing core and the second processing core, and high repetition frequency imaging accumulation results corresponding to multiple imaging areas are spliced. Based on this, the dual-core model separates the control flow and the imaging accumulation process, and the two cores perform parallel processing, so that the processing speed can be improved; an imaging accumulation process is divided into pulse pressure cache and imaging hardcore accumulation by a double-cache technology, and the repetition frequency is improved by optimizing time efficiency through a memory; and the imaging data is divided into a plurality of areas for respective imaging, so that the problem of imaging sheet limitation can be solved.

The invention discloses a ground wire deicing machine optimization method and system based on high-amplitude narrow-pulse-width electric pulses, and relates to the technical field of deicing machine optimization, and the method comprises the following steps: obtaining ice accumulation first data, and carrying out the type classification of ice layers, so as to obtain a swinging ice layer and a hard ice layer; if the ice layer type is a swinging ice layer, obtaining second data of the deicing environment and calculating an ice layer re-freezing occurrence probability, and carrying out secondary classification on the swinging ice layer according to the ice layer re-freezing occurrence probability; if the ice layer type is a hard ice layer, constructing a ground wire electric pulse deicing mathematical model based on the deicing environment second data and the icing first data, and obtaining an initial deicing machine pulse repetition frequency and an initial single pulse duration; respectively weakening the initial deicing machine pulse repetition frequency and the initial single pulse duration to obtain a corrected deicing machine pulse repetition frequency and a corrected single pulse duration; and deicing is carried out according to the corrected pulse repetition frequency of the deicing machine and the corrected single pulse duration, and the hard ice layer after deicing operation is converted into a swinging ice layer.

The invention discloses an intermediate frequency self-calibration method and device for a wind measurement laser radar and a storage medium, and the method comprises the following steps: S1, a data collection system of a pulse laser wind measurement radar collects atmosphere return light signals, and forms a plurality of pulse signal sequences xi = {a0, a1,... am}, and the atmosphere return light signals comprise a signal sampling rate of mHz and a pulse repetition frequency of n; s2, according to the return light signals, a blind area segment in a pulse signal sequence xi = {a0, a1,... am} is searched, and am represents m return light signal data; compared with the prior art, the method uses the return light signal of the pulse laser radar to find the return light signal of the blind area section of the radar; the signals in the blind area are used for power spectrum estimation to obtain the intermediate frequency of the laser radar, so that the function of intermediate frequency self-calibration is achieved, and the fixed intermediate frequency after one-time calibration before delivery is avoided.

Embodiments of the invention include a plasma system. The plasma system includes a plasma chamber; an RF driver configured to drive bursts into the plasma chamber with an RF frequency; a nanosecond pulser configured to drive pulses into the plasma chamber with a pulse repetition frequency, the pulse repetition frequency being less than the RF frequency; a high pass filter disposed between the RF driver and the plasma chamber; and a low pass filter disposed between the nanosecond pulser and the plasma chamber.

Disclosed are devices, systems, and methods for ultrasonically stimulating brain tissue using operating parameters associated with a. target region of a brain. The operating parameters can be determined, for example, by combined ultrasonic stimulation and photometry devices and methods. The operating parameters can include pulse repetition frequency, temporal compression, and intensity. Using selected operating parameters, ultrasound stimulation of the target region of the brain can excite or inhibit brain cell activity.

The invention relates to the field of ultrasonic sleep aiding, and provides an ultrasonic-infrasound coupled sound wave whole-brain sleep regulation and control method and device. The whole-brain sleep regulation and control method based on the ultrasound-infrasound coupling sound waves comprises the steps that electroencephalogram signals of a user are collected through electroencephalogram collection equipment; physiological parameters of the user are obtained through physiological state monitoring equipment; a control device is adopted to control and adjust the fundamental frequency, pulse width, pulse repetition frequency, difference frequency, intensity and other parameters of two columns of ultrasonic waves generated by a sound wave emission device according to the electroencephalogram signals and the physiological parameters; a sound wave emitting device is adopted to generate and emit two columns of ultrasonic waves which are close in frequency and face to face, the two columns of ultrasonic waves are fed into the brain face to face, and the two columns of ultrasonic signals inhibit the cerebral cortex activity when passing through the cerebral cortex; meanwhile, interference occurs in the deep brain target nuclear region, low-frequency infrasound beat frequency waves are formed, electroencephalogram slow wave rhythm resonance is induced, sleep-related neural activities of the deep brain target nuclear region are synchronized, and coordinated regulation and control of the whole brain region are achieved.

The invention provides a satellite-borne bistatic SAR imaging system and method, and the method comprises the steps: employing a coding signal pulse sequence as a periodic transmission sequence for a transmission signal, and enabling any pulses to be in an orthogonal relation; the pulse repetition frequency is set based on the bistatic configuration, and the adopted pulse repetition frequency enables the inter-satellite direct wave and the bistatic SAR ground echo to be received at the same time, and the waveforms of radar emission signals corresponding to the inter-satellite direct wave and the bistatic SAR ground echo are different; on the basis of the setting of a coded signal pulse sequence and the setting of a pulse repetition frequency, inter-satellite direct waves and observation area bistatic SAR echoes which are aliasing together in time are obtained, and the inter-satellite direct waves and observation area bistatic SAR echo signals obtained at the same moment are orthogonal; based on the obtained inter-satellite direct wave and the observation area bistatic SAR echo which are mixed together in time, the inter-satellite direct wave and the observation area bistatic SAR echo are extracted respectively, and the spaceborne bistatic SAR imaging function under the suppression of the inter-satellite direct wave is achieved.

An exemplary communication method is a communication method using a preamble between a first communication device and a second communication device, wherein the first communication device communicates with the second communication device using the type of the preamble determined according to the use purpose of communication from among a plurality of preamble types determined by the pulse repetition frequency of the preamble or the length of the preamble.

The invention discloses a programmable waveform modulation high-power optical fiber laser system, particularly relates to the field of high-power optical fiber lasers, and is used for solving the problem of power monitoring and control instability caused by alias distortion under high pulse repetition frequency. Micro-amplitude random time jitter is implanted, sampling and pulse rhythm coupling are scattered through synchronous mapping of a time mark and a power sequence, and turn-back pseudo fluctuation is blocked from the source; the abstract evaluation mechanism fuses energy domain and time domain features, and uses a single determination identifier to drive sampling frequency adaptive migration, so that a monitoring link is continuously in a co-prime fraction ratio operation interval, and alias distortion root causes are eliminated; the sampling label and the judgment identification jointly trigger a feed-forward gain matrix to form a monitoring evaluation adjustment compensation closed loop, power aftershock is reduced in real time, stimulated scattering and thermal lens linkage amplification are inhibited, and light beam quality stability and energy smooth distribution are maintained.

The invention discloses an operation optimization method and system for hair removal instrument equipment. An operation time period is set, an analysis period is divided, parameters such as wavelength, pulse width and laser pulse repetition frequency are collected in real time, parameter correlation and changes are analyzed through Pearson's correlation coefficients, and an infrared monitoring unit is combined to obtain an infrared image of a target part for energy output analysis. And through weighted average of the parameter change consistency proportion and the energy output difference value, operation abnormity is evaluated, operation early warning information and an optimization scheme are generated, and intelligent operation optimization of the hair removal instrument equipment is realized.

The invention relates to the technical field of synthetic aperture radars, and discloses a dechirp strip SAR waveform design method based on time domain azimuth ambiguity, and the method comprises the steps: obtaining the azimuth output maximum width and synthetic aperture length of an SAR image through calculation; respectively calculating the minimum value and the maximum value of the pulse repetition frequency through the scene size and the synthetic aperture length so as to determine the initial selection range of the pulse repetition frequency; constructing a time domain azimuth ambiguity function, presetting a time domain azimuth ambiguity value, and traversing all pulse repetition frequency values in the pulse repetition frequency initial selection range through the time domain azimuth ambiguity function to obtain a candidate pulse repetition frequency set; in the candidate pulse repetition frequency set, the minimum value of the pulse repetition frequency is used as the final pulse repetition frequency, and the technical problems that the existing time domain azimuth ambiguity is not fully constrained, so that the SAR image has fuzzy artifacts, the imaging quality is influenced and the like are solved.

The present invention discloses a radar HRRP continuous learning method based on a generative adversarial network, comprising the following steps: S1, using measured data including three types of aircraft, namely, a medium-sized propeller aircraft An‑26, a small jet aircraft Cessna, and a large jet aircraft Yark‑42, the radar operates in the C band, has a signal bandwidth of 400 MHz, and a pulse repetition frequency of 400 Hz; S2, processing intensity sensitivity and translation sensitivity in a preprocessing process; S3, using three different HRRP incremental learning task settings under the background of radar HRRP automatic target recognition; S4, training the HRRP data processed by S2 under the three settings according to a continuous learning related method, and redesigning the decoder for the pseudo-replay DGR method to a conditional autoencoder adversarial network CVAEGAN, wherein the CVAEGAN includes an encoder, a decoder, a discriminator, and a classifier; S5, training the HRRP data processed by S2 using a DGR method of the CVAEGAN network.

The present invention relates to a method for generating a semiconductor wafer, comprising the following steps: first, setting a number of times to perform laser scanning, then setting a scanning path and a point spacing for each instance of laser scanning; based on a preset calculation rule for each instance of laser scanning, determining a laser scanning speed and a laser pulse repetition frequency, and determining a corresponding modified spot diameter, a laser pulse energy and an offset distance of the laser focal point relative to a preset stripping surface; focusing a pulse laser on the preset stripping surface or below the preset stripping surface in a crystal ingot, and performing a number n of instances of laser scanning, so as to sequentially form a modified spot and a crack on the preset stripping surface; and stripping the crystal ingot along the preset stripping surface, to obtain a wafer and a remaining crystal ingot. The present invention can not only eliminate burrs on the edge of a wafer, but can also reduce material loss during laser stripping. The method has the advantages of simple process requirements, good modification layer morphology and low wafer stripping difficulty, and is suitable for large-scale industrial application.

Disclosed is a method for generating a digital elevation model of a to-be-considered region on the earth or on another planetary body by using a system of multiple synthetic aperture radar (SAR) platforms, in a single pass, by comprising the following steps providing a system of several SAR platforms which are arranged with multiple along-track and cross-track baselines, wherein at least one of the SAR platforms repeatedly transmits pulses towards the to-be-considered region, i.e., in the slant range direction. The receiving SAR platforms receive the echo signals (raw data) and are provided with antennas, whose lengths in the along-track direction are smaller than the length required to have the 3 dB Doppler bandwidth of the received signal equal to the pulse repetition frequency, whereby the 3 dB Doppler bandwidth is defined as the width of the interval of Doppler frequencies for which the intensity of the response from a target on the ground is at least half of that of its maximum. Range compression on the raw data is performed to obtain range-compressed data. The range-compressed data of all receiving SAR platforms are jointly processed into a tomogram by a 2-D beamforming in the along-track and cross-track dimensions and the digital elevation model is estimated from the tomogram.

The application provides a high-resolution wide-surveying-band imaging method, device and storage medium, and belongs to the technical field of data processing. The method is applied to a synthetic aperture radar, and comprises the following steps: the synthetic aperture radar randomly selects a current pulse repetition frequency in a predetermined pulse repetition frequency value range every preset interval, and adjacent two current pulse repetition frequencies are different and discontinuous; according to the current pulse repetition frequency, the synthetic aperture radar transmits a pulse signal and receives a target-reflected echo signal; and the fast iterative soft threshold algorithm is used to process the target-reflected echo signal, so that a sparse reconstructed target imaging result is obtained. The application aims to solve the problem of high-resolution wide-surveying-band of a single-channel SAR system.

The invention relates to the technical field of road collapse detection, in particular to a road collapse detection method and device. According to the technical scheme, equipment is installed below rearview mirrors on the two sides of a vehicle, and the interior of the equipment comprises four modules including a laser emission module, a laser detection module, a GNSS speed measurement module and a road collapse judgment module. The laser emission module receives a sending instruction sent by the road collapse judgment module and emits laser to the front of a road, the laser falling point may be about 100 m in front of a vehicle, and the value can be adjusted according to different installation inclination angles of the laser emission module; according to the invention, the laser pulse repetition frequency can be set according to the following formula: 0.14 v / delta < = fr < = 0.28 v / delta. The device is installed on the rearview mirrors on the two sides of the vehicle, can continuously detect whether the road ahead collapses or not in the high-speed running process of the vehicle, and can give an early warning to a driver in time if collapse is found, so that the tragedy of vehicle falling is avoided.

The invention discloses a high-precision photon digital-to-analog conversion system based on noise shaping, which is characterized in that a mode-locked laser generates an optical pulse sequence, optical pulses enter a dispersive medium, and periodic pulses are processed by using a fractional order Talbot effect, so that the pulse repetition frequency is improved; the Delta-Sigma (Delta Sigma) modulation module processes a preset target signal and shifts noise to a high frequency band based on an oversampling technology and noise shaping to realize conversion from an analog signal to a digital signal; the pulse signal with the repetition frequency increased is input into the electro-optical modulation module to serve as a sampling source, and a digital signal generated by the delta-sigma modulation module is input into the electro-optical modulation module for intensity modulation, so that the optical pulse carries the characteristics of frequency change and noise shaping of the signal, and fusion from electric signal modulation to optical signal modulation is completed; inputting the pulse signal after electro-optical modulation into a photoelectric detector, and converting an optical signal into an electric pulse signal; the electric pulse signal enters a filtering module, noise in the electric signal is filtered out, and an analog signal is obtained.

The invention relates to the technical field of intelligent sensors, in particular to an unmanned aerial vehicle track intelligent tracking method based on a millimeter-wave radar, which comprises the following steps: receiving echo signals collected by the front end of the millimeter-wave radar, carrying out constant false alarm rate detection and Doppler frequency shift extraction on the echo signals, generating an unmanned aerial vehicle target space coordinate set, and carrying out target tracking on the unmanned aerial vehicle. And mapping the target space coordinate set of the unmanned aerial vehicle to a three-dimensional Euclidean space. According to the method, a non-convex optimization objective function containing beam switching time cost and precision constraint is constructed, and mathematical optimal solution of radar beam resources is realized. The generated adaptive scheduling instruction is used for adjusting the pulse repetition frequency and the beam residence time, it is ensured that radar front-end parameters dynamically evolve along with the target state, overall centroid tracking is emphasized for rigid body formation so as to save resources, independent high-frequency refreshing is emphasized for discrete targets so as to ensure the precision, and the accuracy is improved. And the continuity and robustness of trajectory tracking of the unmanned aerial vehicle in a complex electromagnetic environment are improved.

A method of measuring a delay time of a propagation of a signal in a line in a circuit structure, the method comprises irradiating the line by pulses of a charged particle beam, wherein a pulse repetition frequency of the pulses of the charged particle beam is varied. The method further comprises measuring, for each of the pulse repetition frequencies, a secondary charged particle emission responsive to the irradiating the line by the pulses of the charged particle beam at the respective pulse repetition frequency, and deriving the delay time of the line based on the secondary charged particle emission responsive to the varying of the pulse repetition frequency.

For shear wave imaging with ultrasound, the apparent pulse repetition frequency is increased by combining displacements from different lateral locations. Different combinations based on different shear wave velocities and corresponding time shifts and / or attenuations and corresponding scalings are tested to find a smooth displacement profile for the combination. Once the smooth displacement profile is found, the corresponding shear wave velocity is estimated or determined.

The embodiment of the application provides a parameter inversion method, device and electronic equipment, wherein the parameter inversion method comprises: performing interference suppression on a received incomplete SAR signal to obtain a non-interference signal matrix; wherein the non-interference signal matrix comprises a plurality of non-interference pulse signals with time sequence continuity, and the incomplete SAR signal represents that the SAR signal is incomplete; sequentially performing data processing on each non-interference pulse signal to obtain pulse parameters of each non-interference pulse signal; the pulse parameters at least comprise a stationary phase center position, a termination point, a pulse bandwidth, a pulse signal frequency modulation rate and a peak position; based on the pulse parameters of each non-interference pulse signal, signal parameters of the incomplete SAR signal are inverted to obtain transmission parameters of the incomplete SAR signal; the signal parameters at least comprise a pulse width, a bandwidth, a frequency modulation rate, a pulse repetition interval and a pulse repetition frequency.