212 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 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 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 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 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 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 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.

The present invention discloses a method for reference clock phase synchronization and fine adjustment and a pulse generator. The method includes: Step 3, the host computer or the accelerator control system issues parameter configuration; Step 4, determine the reference clock selection mode; Step 5, when an external reference clock is selected, the pulse generator receives an external reference clock signal with a frequency of 10 MHz to 500 MHz; Step 6, according to the pulse parameter values set in Step 3, calculate the theoretically pulse repetition frequency count value, pulse width count value, and pulse delay count value. The present invention calculates the theoretically pulse repetition frequency count value, pulse width count value, and pulse delay count value through the parameter configuration issued by the host computer or the accelerator control system, enabling the pulse generator to generate stable and adjustable pulse signals with ns-level precision and to maintain phase synchronization with the input reference clock under different working conditions to meet different particle acceleration and control requirements.

FIELD: protective coatings.SUBSTANCE: method for forming a protective oxide-ceramic coating on the surface of products made of valve metals and alloys by the plasma electrolytic oxidation method involves immersing the product as an electrode together with a counter electrode in a bath filled with an aqueous alkaline electrolyte, and supplying rectangular pulses of anodic and cathodic voltage to the electrodes using a pulsed power source. Anode and cathode voltage pulses are supplied with a current-free pause between them, the value of which is 4.8 times the duration of the anode pulse. The amplitude values of the cathode voltage pulses range from 85 to 149 V with a pulse repetition frequency from 1000 Hz to 4000 Hz, while the current pulse repetition frequency is additionally regulated.EFFECT: obtaining oxide-ceramic coatings with specified properties under reduced energy conditions, with lower values of cathode voltage.1 cl, 2 ex

A laser system for multiphoton microscopy comprises a seeder oscillator, fast modulator, amplifier, second modulator, and optical parametric amplifier configured to produce pulses with variable pulse spacing temporally synchronized to a scanner having sinusoidal motion. The variable pulse spacing ensures each pixel receives substantially the same number of laser pulses, eliminating uneven energy distribution of fixed repetition rate systems. The scanner operates at 4-12 kHz frequencies while the seeder oscillator produces femtosecond pulses at 10-100 MHz with 10-100 ns pulse spacing. The optical parametric amplifier outputs wavelengths from 600-1900 nm, with 1300-1700 nm optimized for three-photon microscopy. Methods include synchronizing pulse timing to scanner motion and varying interpulse intervals across scan lines. For 8 kHz scanners with 512 pixels per line, the system achieves 32% energy reduction compared to constant pulse spacing while maintaining 100-150 mW average power on biological samples, preventing thermal damage and enabling video rate imaging.

A first radar transmitter capable of transmitting a pulse-modulated radar signal to a target, a second radar transmitter capable of transmitting a radar signal to the target, a radar receiver capable of simultaneously receiving a radar signal transmitted by the first radar transmitter and reflected by the target and a radar signal transmitted by the second radar transmitter and reflected by the target, and a signal control unit to control one or more of a carrier frequency, a pulse recurrence frequency, and a duty ratio of a pulse-modulated radar signal, and a carrier frequency of a non-pulse-modulated radar signal with respect to the first radar transmitter or the first radar transmitter and the second radar transmitter are provided.

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.

A method may include identifying a time window of a procedure. The method may also include obtaining operational information of the time window. The operational information may include a limit of pulse repetition frequency (PRF) acceleration and a plurality of preliminary radio frequency (RF) PRFs. The method may also include determining a plurality of updated RF PRFs by updating the plurality of preliminary RF PRFs. A rate of variation between any two adjacent updated RF PRFs may be less than or equal to the limit of PRF acceleration. The method may also include causing an RF source to generate electromagnetic waves at the plurality of updated RF PRFs in the time window.

The application provides a pulse repetition frequency type recognition method and device based on graph domain mapping and feature enhancement, and relates to the technical field of radar signal processing. The method comprises the following steps: determining a pulse repetition frequency sequence corresponding to a screened pulse repetition frequency; taking the reciprocal of the pulse repetition frequency sequence to obtain a pulse repetition interval sequence; dividing the pulse repetition interval sequence into multiple subsequences according to a preset length; transforming the multiple subsequences into a Gram difference angle field image according to a graph domain mapping algorithm, and dividing the image into training samples and test samples; constructing a pulse repetition frequency type recognition network, inputting the training samples into the pulse repetition frequency type recognition network, training the pulse repetition frequency type recognition network, and obtaining a trained pulse repetition frequency type recognition network; and inputting the test samples into the trained pulse repetition frequency type recognition network to recognize multiple pulse repetition frequency types. In this way, the recognition accuracy and robustness of the pulse repetition frequency type are improved in a complex non-ideal scene with a high proportion of missed pulses and false pulses.

The application discloses an engine rotor multi-parameter measurement system and method, and the system comprises a first optical comb, a second optical comb, a polarization maintaining optical fiber amplifier, a polarization maintaining optical fiber beam splitter, an integrated polarization maintaining optical fiber ring, an integrated polarization maintaining optical fiber beam combiner, a plurality of high-temperature-resistant optical fiber probes, a high-speed photoelectric detector and a data acquisition and processing system; the pulse repetition frequency of the first optical comb is greater than that of the second optical comb, and the two have a high repetition frequency difference; the plurality of high-temperature-resistant optical fiber probes respectively generate reference light pulses and measurement light pulses; the scanning light pulses emitted by the second optical comb respectively interfere with the plurality of reference light pulses and the plurality of measurement light pulses to generate double-comb interference reference signals and double-comb interference measurement signals; through processing of the reference signals and the measurement signals of each channel, the engine rotor speed, the blade tip clearance, the blade tip timing and the blade vibration parameters are obtained. The application has the advantages of high measurement speed, high measurement accuracy and multi-parameter synchronous measurement.

The invention belongs to the technical field of pulse power, and particularly discloses a frequency superposition pulse circuit based on an avalanche transistor, a generator and a control method. According to the frequency superposition pulse circuit, the frequency superposition pulse circuit is composed of the multiple pulse units, the finally output repetition frequency pulse is composed of the outputs of the multiple pulse units, superposition on the frequency is achieved, and the pulse repetition frequency can be improved while the pulse amplitude can be effectively guaranteed. The pulse repetition frequency of a single pulse unit can be effectively reduced while the purpose of high repetition frequency output is achieved, the problem that the repetition frequency of output pulses of a single Marx circuit based on an avalanche transistor is insufficient is solved, meanwhile, the problem that the avalanche transistor and a resistor in the single pulse unit generate heat under high repetition frequency pulses can be effectively relieved, and the pulse repetition frequency of the single pulse unit can be effectively reduced. And thermal damage of the device under high repetition frequency pulses is avoided. The n isolation diodes in the same pulse unit are connected in series, so that the output end of the whole pulse unit generates high voltage, an isolation effect is achieved, and false triggering of m pulse units is avoided.

The present application relates to radar target recognition tracking technical field, especially in the field of phased array radar multi-target adaptive identification method and system, including: first, the radar echo and platform attitude data are acquired, the velocity distribution is extracted and the target is divided into two groups of high speed / low speed; for high speed group, the displacement prediction parameter is extracted to adaptively adjust the beam pointing sequence, for low speed group, the pulse repetition frequency is determined based on the residence time window and the frequency shift characteristics, and the resource allocation scheme is generated; then the attitude correction result is integrated into the beam control parameter, the adaptive observation sequence is generated combined with the resource scheme, and the trajectory information is tracked in real time; again, the Doppler shift deviation is estimated according to the trajectory, the gain / bandwidth and other signal processing parameters are compensated online, and the corrected target position and velocity are output. The present application realizes three-dimensional high-precision identification, continuous stable tracking and efficient resource utilization in complex dynamic scene.