36 results about "Phase Code" patented technology

The application provides a remote acoustic signal pickup method and system based on phase coding microwave sensing, comprising: constructing a phase coding matrix, and performing phase shift control on the transmission signals of multiple transmission antennas; controlling the multiple transmission antennas to simultaneously transmit a linear frequency modulation continuous wave signal, so that the main lobe of a synthesized beam is directed towards the direction of a to-be-detected acoustic source or the direction of a target medium; using one or more receiving antennas to receive echo signals of the acoustic source target, to obtain a corresponding number of baseband signals; performing acoustic vibration phase demodulation on the corresponding number of baseband signals, to extract vibration information of the surface of the medium target caused by the vibration information of the acoustic source or caused by the excitation of the acoustic wave; and reconstructing the acoustic signal, to realize remote acoustic pickup. The application overcomes the problems of weak echo signals, low signal-to-noise ratio, large adjacent target interference and low quality of reconstructed acoustic signals in remote acoustic pickup, and improves the signal-to-noise ratio and sensing distance of remote acoustic pickup.

Disclosed are techniques for wireless sensing. In an aspect, a sensing node receives, from a sensing entity, a. configuration to report interference measurements, obtains, at a first time, one or more sensing measurements of one or more first sensing reference signals transmitted by a transmitter sensing node, obtains, at the first time, one or more interference measurements of one or more second sensing reference signals transmitted by one or more aggressor sensing nodes, and transmits, to the sensing entity, an interference measurement report including at least the one or more interference measurements.

The invention discloses a composite modulation signal blind identification method based on time-frequency analysis, which comprises the following steps of: firstly, judging and classifying input pulse signals, and then respectively carrying out identification and parameter estimation on determined signal types. According to the scheme, down-conversion analysis processing, signal time-frequency analysis processing and signal classification identification decision processing are firstly carried out on AD sampling intermediate frequency data sent by a digital signal processing board FPGA to obtain an identification result of a radar signal intra-pulse modulation type, and then corresponding parameter estimation is carried out according to the radar signal intra-pulse modulation type. According to two composite modulation styles of frequency coding and linear frequency modulation combination and frequency coding and two-phase coding combination, on the basis of time-frequency parameter characteristics of various composite modulations, related characteristic parameters are accurately extracted, a modulation type identification process is constructed, and time-frequency analysis is performed on radar signals through fast Fourier transform and phase correlation, so that the identification accuracy of the radar signals is improved. And furthermore, intra-pulse parameter estimation is accurately carried out on the radar signal.

The invention provides a photoelectric oscillator capable of being used for generating tunable phase coding microwave pulses. The photoelectric oscillator is composed of a tunable laser, a polarization controller, a phase modulator, a dual-drive Mach-Zehnder modulator, an optical circulator, a phase shift fiber bragg grating, a single-mode fiber, a photoelectric detector, an electric amplifier, a microwave source and an arbitrary waveform generator. The invention develops the active mode-locked photoelectric oscillator for generating the phase-coded microwave pulse signal, which is simple in structure and good in tunability. On the basis of an active mode-locked optoelectronic oscillator, a phase modulator is driven by a phase coding signal, so that the duration of each voltage polar code is kept consistent with the loop delay of the optoelectronic oscillator, and a phase-coded coherent microwave pulse sequence is generated. The signal has the advantage of large time bandwidth product, can give consideration to the detection distance and distance resolution of the radar, and has the characteristics of interference resistance, low interception and the like.

The invention belongs to the technical field of metasurfaces and plane lenses, and particularly relates to a focusing metasurface lens with an anti-shielding function, the lens is composed of 40 * 40 units with the period of 7.5 mm, each unit comprises a top layer metal annular patch, a dielectric layer and a bottom layer metal patch, the relative dielectric constant of a dielectric substrate is 2.65, and the relative dielectric constant of the dielectric substrate is 2.65. The units realize anisotropic response through circumferential notch design, a stable 180-degree phase difference is formed by adopting a mirror image inversion structure, the 1-bit phase modulation requirement is met, the array performs phase coding in the radial direction according to an Airy function, and a hollow annular layout is adopted, so that the self-bending and self-repairing characteristics of Airy beams are effectively utilized, and the phase modulation efficiency is improved. The electromagnetic wave can bypass physical shielding of an axis area, field intensity reconstruction is realized at a set focus, and the design can remarkably improve focusing gain and energy recovery capability of a system in a shielding environment while maintaining high cross polarization conversion efficiency in Ku frequency band application of 13GHz and the like.

The invention provides a phase coding QKD (Quantum Key Distribution) method, which comprises the following steps that: a transmitting end modulates an optical pulse into four optical pulses, a receiving end modulates each optical pulse into four optical pulses and forms six interference pulses, and a quantum key is negotiated and shared based on the six interference pulses; the invention also provides a phase coding QKD system, which comprises a transmitting end and a receiving end and is used for realizing the phase coding QKD method disclosed by the invention. According to the invention, the code rate and the security of the QKD system can be obviously improved, and the method has a good application prospect.

The invention discloses a deception jamming method and device for an azimuth phase coding SAR (synthetic aperture radar), and belongs to the technical field of electronic support system synthetic aperture radar countermeasure. The method comprises the following steps: intercepting an SAR signal, carrying out two-dimensional structured phase stripping by constructing an inverse distance modulation operator and an inverse azimuth modulation operator, and estimating to obtain an azimuth phase sequence; carrying out complex domain differential operation on the estimated azimuth phase sequence, constructing a phase consistency measurement index and minimum consistency order mapping, and identifying a coding structure of the phase consistency measurement index and the minimum consistency order mapping; constructing a linear least square problem based on an identification result, and reconstructing an azimuth phase sequence; and performing phase consistent modulation including convolution modulation on the intercepted signal to generate a deception jamming signal. According to the method, complete matching of the interference signal and the SAR receiving filter is realized, and effective deception interference can be implemented on a new system SAR adopting random, primary, secondary and grouped phase coding.

Provided is a method for solving radar ambiguity and occlusion based on an orthogonal two-phase coded signal. The method includes: generating and optimizing an orthogonal two-phase coded signal set by means of a walsh matrix and a genetic algorithm, and alternatively, obtaining an orthogonal two-phase coded signal set through an exhaustive method, depending on a chip length; determining the radar period and the number m of transmission pulses in a period according to the radar farthest detection range and the pulse repetition interval (PRI), and selecting m signals from the orthogonal two-phase coded signal set, to constitute a group of orthogonal two-phase coded pulse signals; and accumulating echoes of transmitted pulse signals, to generate an echo matrix, performing frequency domain pulse compression, to obtain a processed new matrix, and performing moving target detection on the matrix.

Aspects of the present disclosure are directed to systems and methods of operating a MIMO radar system for automotive applications, including transmitting FMCW signals from first and second transmitters; wherein the signals each comprise a plurality of chirps, and each signal comprises phase modulation of the FMCW signal within each chirp by a respective CDMA phase code to produce respective first and second PM-FMCW signals; receiving a composite signal, wherein the composite signal comprises at least one reflection of the first PM-FMCW signal and the second PM-FMCW signal; and in the digital domain, processing a plurality of down-converted and pre-processed groups of samples of the composite signal by: applying a frequency response correction; applying a group delay filter; the CDMA phase code is removed; the 2D-FFT is applied; and removing a phase code cross-correlation residual from the corresponding transformed demodulated sample group by calculating an estimated residual and subtracting the estimated residual from the corresponding transformed demodulated signal.

The application discloses a multi-angle synthetic illumination super-diffraction imaging system and method based on coding modulation, relates to the field of optical imaging technology, and utilizes a spatial light modulator (SLM) to code and modulate a coherent illumination light field to realize the effect of similar angle-variable illumination without any mechanical device driving laser scanning. In addition, the application also freely adjusts the illumination spot size through phase coding to realize different illumination field angles, effectively avoids problems such as limited field angle and excessive dispersion of illumination energy and the like. The application can effectively improve the diffraction blur problem caused by the limited optical aperture in macro imaging, and the system is simple and compact, does not need high-precision displacement device assistance, and can realize a larger equivalent aperture and higher imaging resolution.

This application discloses a system startup status detection method, apparatus, storage medium, and device. The method includes: firstly, starting the target system using startup phase code, and obtaining the timestamps of the initialization completion times of each corresponding functional module using stub functions in the startup phase code; then, calculating the startup time of the target system using the timestamps; and obtaining startup status data corresponding to each core of the ECU during the startup process; and finally, generating a detection result of the target system startup status based on at least one of the startup time and startup status data of the target system. Because this application adaptively inserts stub functions into the startup phase code of the target system, it can obtain the timestamps of the initialization completion times of each functional module when starting the target system, thereby calculating the overall startup time of the target system more quickly and accurately, and thus improving the efficiency and accuracy of the target system startup status detection.

The invention discloses a conformal non-reciprocal amplitude and phase independent adjustable digital coding metasurface, the coding metasurface is composed of a plurality of units, accurate regulation and control of the phase and the amplitude of transmission electromagnetic waves can be realized simultaneously by adjusting the opening and the orientation of a C-shaped circular ring of a middle layer of each unit, and the phase and the amplitude are mutually independent. The unit material can be bent to realize conformality, and the super surface is a conformal coding super surface. Two metasurface units are arranged in a staggered mode, amplitude phases of the two metasurface units are coded respectively, then the metasurface is integrally bent, the metasurface achieves different function regulation and control on electromagnetic waves incident in the forward direction and the reverse direction, and the non-reciprocal conformal metasurface is achieved. The conformal and nonreciprocal amplitude and phase independent adjustable digital coding metasurface provided by the invention is conformal and nonreciprocal, can effectively improve the information capacity and degree of freedom of the metasurface, realizes multifunctional multiplexing, and has important application prospects in the fields of wireless communication, radar, imaging, signal processing and the like.

This invention discloses an angle-prior-assisted intelligent metasurface phase coding design method for two-dimensional DOA estimation. The method includes: constructing a system model for two-dimensional DOA estimation with a single receiving channel on the intelligent metasurface; deriving the explicit relationship between the CRB of the two-dimensional DOA estimation parameters and the phase coding matrix; utilizing the prior range information of the target two-dimensional angle, constructing a phase coding matrix optimization problem with a unit modulus constraint, aiming to minimize the average CRB; and efficiently solving this non-convex problem using the Riemannian manifold optimization algorithm to obtain the optimal phase coding matrix. This invention directly links the coding design to the theoretical performance lower bound. By optimizing the coding to focus beam energy in the target prior angle region, it significantly improves the accuracy of two-dimensional DOA estimation for azimuth and elevation angles within the angle prior range, reduces the required measurement overhead, and exhibits good robustness under one-bit phase coding.

The invention relates to the technical field of industrial process measurement and automatic instruments, in particular to a frequency-modulated continuous wave radar storage tank liquid level measurement method which comprises the following steps: acquiring an orthogonal baseband signal and generating a complex distance spectrum based on an uphill linear frequency-modulated signal, a downhill linear frequency-modulated signal and complementary phase coding; extracting reference echoes to calibrate the complex distance spectrum and determine a coding phase alignment angle, and subtracting the fixed structure echoes by using the fixed structure echo dictionary to obtain a fixed structure echo stripping complex distance spectrum and generate residual energy; complementary phase coding coherent combination is carried out based on the coding phase alignment angle, and candidate distance observation and candidate feature vectors are generated according to time delay consistency; and outputting liquid level estimation and confidence coefficient by adopting dynamic programming, performing change point detection on residual energy to generate a dictionary freezing mark and a dictionary rollback mark, generating an active disambiguation control instruction by combining the confidence coefficient, and updating emission scheduling parameters. The false peak and jump are effectively reduced, and the measurement stability and the adaptive anti-interference capability are improved.

Disclosed are techniques for wireless sensing. In an aspect, a sensing node receives, from a sensing entity, a configuration to report interference measurements, obtains, at a first time, one or more sensing measurements of one or more first sensing reference signals transmitted by a transmitter sensing node, obtains, at the first time, one or more interference measurements of one or more second sensing reference signals transmitted by one or more aggressor sensing nodes, and transmits, to the sensing entity, an interference measurement report including at least the one or more interference measurements.

The invention provides a digital clock data recovery circuit and method. The digital clock data recovery circuit comprises an analog-to-digital converter used for sampling an analog input signal under the control of a sampling clock signal and converting the sampled signal into a digital signal; the error detector is used for carrying out phase error detection according to the digital signal to obtain a phase error estimation value; the frequency deviation detector is used for acquiring a frequency deviation estimation value according to the phase error estimation value; the loop filter is used for filtering according to the phase error estimation value and the frequency deviation estimation value and outputting a filtering signal; the phase code generator is used for generating a phase code according to the filtering signal; and the phase interpolator is used for generating the sampling clock signal according to the phase code so as to control the sampling phase of the analog-to-digital converter. The digital clock data recovery circuit can quickly capture clock frequency deviation.

The invention discloses a Loran C receiver signal searching method and system based on an FPGA, and the method specifically comprises the steps: carrying out the filtering processing of an input AD sampling signal, filtering out-of-band noise, and obtaining a filtered signal; performing down-sampling processing on the filtered signal to obtain a down-sampled signal; performing accumulation processing on the down-sampling signal to obtain an accumulated signal; performing sliding reading and sign bit extraction on the accumulated signal to obtain a sign bit signal; performing sliding correlation detection on the sign bit signal and the fixed primary and secondary station phase coding sequence to obtain a correlation detection result; and carrying out peak value judgment and main and auxiliary station time difference judgment on related detection results, and identifying main and auxiliary station signals of the station chain. According to the invention, rapid and accurate capture of the Roland C signal is realized, the requirements of the system for computing power and storage resources are reduced, and the requirements of a dynamic scene and real-time performance are met.

The application discloses a plane prescription lens phase coding method and system applied to the technical field of plane prescription microstructure design, and the method comprises the following steps: obtaining prescription parameters, wearing posture parameters and manufacturing assembly constraints, performing equivalent compensation on the prescription and executing axis position rotation in a plane lens coordinate system, further generating a target wavefront, a two-dimensional phase field and a height field, performing local power continuity checking and manufacturability checking on the phase field, and outputting a phase diagram, a height diagram, a manufacturing file and a parameter list, and the system comprises an input module, a coordinate transformation module, a phase coding module, a manufacturability evaluation module and an output module. Through the above scheme, the spherical lens, the cylindrical lens and the axis position can be written into the plane microstructure, and the local image quality continuity and the manufacturing realizability can be controlled simultaneously.

The present invention provides a method and system to correctly sample, at a central location, a signal at a second clock frequency from a remote antenna when the signal is at a first clock frequency. The present invention provides an improved method of incoherent clocking to correctly sample a signal from a remote antenna at a clock frequency of a central location, such as a central site of a radio telescope array. The signal contains a “tracer” which is related to the frequency of the remote antenna. The tracer phase is written into a dual-port memory at the first clock frequency and then read from the memory at the second clock frequency. The tracer phase is transferred across digital clock domains using Gray-doe methods so that phase coding errors do not occur.

The application discloses a method for generating a despread soft sequence of an MSK-soft spread spectrum system based on iteration, and relates to the field of communication, and comprises the following steps: S1, constructing an MSK-spread spectrum signal receiving model; S2, receiving a received signal of a sampling point by the MSK-spread spectrum signal receiving model; and S3, under the assistance of an initial word C0 of a spread spectrum code stored in the MSK-soft spread spectrum system, other code phase code words are constructed by using a traditional spread spectrum code word based on a cyclic shift, and the characteristics that MSK signal phases change continuously symbol by symbol are used to construct a despread soft sequence of the MSK-soft spread spectrum system. The despread soft sequence of the MSK-CCSK is generated by the above method, so that the hardware RAM resource can be saved, and the design of an MSK-CCSK despreader is simplified. Compared with a traditional method, the application theoretically explains the corresponding relationship between the construction of the despread soft sequence of the MSK-CCSK and the construction of an MSK-CCSK spread spectrum sequence, and is helpful to further understanding of the principle of the MSK-CCSK system.

A circuit and a method for digital clock data recovery are provided. The circuit comprises an analog-to-digital converter, an error detector, a frequency deviation detector, a loop filter, a phase code generator, and a phase interpolator. The analog-to-digital converter samples an analog input signal under the control of a sampling clock signal to obtain a sampled signal, and converts the sampled signal into a digital signal. The error detector performs phase error detection based on the digital signal to obtain phase error estimation values. The frequency deviation detector obtains a frequency deviation estimation value based on the phase error estimation values. The loop filter filters and outputs a filtered signal based on the phase error estimation values and the frequency deviation estimation value. The phase code generator generates a phase code based on the filtered signal. The phase interpolator generates the sampling clock signal based on the phase code.

This invention proposes an LFM signal based on random inter-pulse frequency and intra-pulse phase coding modulation, relating to the field of electromagnetic wave waveform modulation technology. This signal inherits the high resolution of LFM signals, has lower range-Doppler (RD) sidelobes, and eliminates the RD coupling effect, so that the false targets generated by ISRJ only produce a sparse deception effect without spreading or drifting on the RD plane. This invention further designs a corresponding signal processing method, which achieves anti-intermittent sampling and forwarding interference by transmitting the modulated signal RIF-PCLFM, improving waveform detection capability and interference suppression performance, and enhancing interference processing efficiency.

The application provides a phase coding-non-match filter joint design method for resisting SAR combined jamming, and relates to the technical field of synthetic aperture radar, and the method comprises the following steps: a phase coding waveform and a non-match filter joint optimization model of a combined jamming scene of intermittent sampling repeater jamming and narrowband radio frequency jamming is established; spectrum constraints and constant modulus constraints are applied to the transmitting waveform, and constant energy constraints are applied to the non-match filter; the joint optimization model is decomposed into a transmitting waveform optimization subproblem and a receiving non-match filter optimization subproblem; the above optimization steps are repeatedly executed until a preset convergence condition is met or a maximum iteration number is reached, and finally, a phase coding waveform and a non-match filter for resisting SAR combined jamming are output. Through the cooperative joint optimization of the transmitting waveform and the receiving non-match filter, the combined suppression of the intermittent sampling repeater jamming and the narrowband radio frequency jamming can be realized, and the low sidelobe and high mainlobe shape preserving performance required by SAR imaging can be ensured.

This invention discloses a distributed and scalable intelligent method and system for generating false targets using time-modulated metasurfaces, relating to the fields of novel artificial electromagnetic metamaterials and radar countermeasures. The method includes: dynamically modulating the complex reflection coefficient by controlling time-modulated metasurface units, constructing a 1-bit phase coding mechanism and modulation waveform library; generating false targets in the range dimension and range-velocity two-dimensional space using intra-frame and inter-frame time modulation respectively, and solving for the optimal time modulation sequence using a physically constrained particle swarm optimization algorithm; extending the single-node method to a multi-node distributed system, and coherently superimposing echoes through multi-node sequence joint design to generate distributed false targets matching a preset template at the radar receiver. This invention can achieve a range-velocity two-dimensional controllable, high-fidelity false target cluster with strong anti-interference capabilities, suitable for radar target camouflage and protection scenarios.

The present disclosure provides a radar front end chip that includes a plurality of encoders, each encoder of the plurality of encoders to receive a digitized radar signal and to encode the digitized radar signal with a phase code to generate one of a plurality of phase-coded digitized radar signals. The radar front end chip also includes a combiner to combine the plurality of phase-coded digitized radar signals into a digital radar data stream for transmission to a central radar processor.

Embodiments of this disclosure provide a phase control device, method, and electronic device. The phase control device includes a phase detector, a phase calibration module, and a phase adjustment module. The phase detector is configured to receive a first clock signal and a second clock signal with the same frequency, compare the phases of the first and second clock signals, and output an indication signal. The phase calibration module is configured to receive the indication signal, generate and send a phase code to the phase adjustment module. The phase adjustment module is configured to receive the phase code and a third clock signal, and process the third clock signal according to the phase code to obtain a second clock signal. This phase control device flexibly adjusts the phase of the clock signal, reducing the latency of cross-clock domain data transmission and improving the performance of cross-clock domain data transmission.

The application provides a narrowband modulation and demodulation method and system suitable for cross-border magnetic induction communication, and belongs to the field of magnetic induction communication. ‑2 The application provides a minimum shift keying (QM-VMSK / 2) encoding modulation method based on quadrature modulation, which realizes parallel transmission through quadrature modulation to double the data rate under the condition of keeping the same bandwidth as the minimum shift keying (VMSK) encoding modulation signal; and a decoding method based on double-phase code detection, which has better anti-noise interference ability compared with the detection method based on zero-crossing detection and double-phase code pulse width discrimination, and has a signal-to-noise ratio gain of more than 2.5 dB when the bit error rate is 10 ‑2 The QM-VMSK / 2 modulation and demodulation technology can provide a narrowband modulation method for underwater magnetic induction communication, reduce the distortion of high-rate signals in the underwater dispersion channel, realize high-rate cross-border magnetic induction communication under the condition that the carrier frequency and the data rate have the same order of magnitude, and improve the communication range x data rate performance limit of magnetic induction communication.

The invention relates to the field of radar signal processing and waveform design, and relates to a photo-generated multipath quadrature phase coding chirp signal optimization method and system based on a non-dominated sorting genetic algorithm. The method comprises the following steps: firstly, generating a multi-channel phase coding sequence population through initialization; then constructing a multi-target fitness function taking minimization of a signal set autocorrelation peak side lobe and a cross-correlation peak as a target; thirdly, performing iterative optimization on the population by using a non-dominated sorting genetic algorithm (NSGA-II), and finally obtaining a Pareto optimal solution set representing different performance tradeoff; and finally, selecting an optimal coding sequence from the solution set according to system requirements, and driving a photon signal generation system to generate physical multi-path orthogonal phase coding frequency chirp radar signals. According to the invention, the advanced multi-target optimization algorithm is combined with the microwave photon technology, and higher radar detection performance is obtained while the anti-interference capability between channels and the correlation of signals are improved.

The present application relates to the technical field of industrial process measurement and automation instrumentation, and particularly relates to a frequency-modulated continuous wave radar tank liquid level measurement method, which comprises the following steps: obtaining a quadrature baseband signal and generating a complex range profile based on an up-slope linear frequency modulation signal, a down-slope linear frequency modulation signal and complementary phase coding; extracting a reference echo to calibrate the complex range profile and determine a coding phase alignment angle, using a fixed structure echo dictionary to subtract a fixed structure echo to obtain a fixed structure echo stripping complex range profile and generate residual energy; performing complementary phase coding coherent synthesis based on the coding phase alignment angle, generating a candidate distance observation and a candidate feature vector according to time delay consistency; outputting a liquid level estimate and a confidence level using dynamic programming, detecting a change point of the residual energy to generate a dictionary freezing flag and a dictionary rollback flag, generating an active disambiguation control instruction in combination with the confidence level, and updating a transmission scheduling parameter. The method effectively reduces false peaks and jumps, and improves measurement stability and adaptive anti-interference capability.