300 results about "Chirp" patented technology

The invention discloses an underwater acoustic signal communication and positioning integrated method. The existing method does not jointly consider the problem of channel resource occupation caused by integration of communication and positioning. According to the method, mutually orthogonal Chirp subcarriers are used as communication signals, meanwhile, long Chirp signals are used as pilot frequency, and the pilot frequency and the communication signals are overlapped together to be sent at a sender, so that extra channel overhead caused by additional pilot frequency is saved, and the signal sending time interval is shortened. A receiver uses a plurality of pilot signals to perform joint Doppler estimation and compensation and time of arrival estimation, and the result of the time of arrival estimation is used for a positioning system and a communication system on the one hand. According to the demodulation mode, correlation calculation is carried out by using different Chirp subcarriers, and symbol demodulation is carried out according to correlation values. According to the communication and positioning integrated waveform design method, the signal sending time interval can be shortened, the system complexity can be reduced, and good communication performance is achieved.

A radar system injects a calibrated current at a signal generator during a reset portion and acquisition portion of each chirp period. The signal generator employs “gear-switching” to reduce PLL bandwidth during an acquisition phase and to increase the phase lock loop (PLL) bandwidth during a reset phase. By employing gear switching to change the bandwidth of the PLL circuit during the different portions of each chirp period, the length of the reset period is reduced, thus improving overall efficiency of the radar system while maintaining good performance.

A human body breathing and heartbeat signal estimation method based on a multi-channel frequency modulation continuous wave millimeter wave radar (FMCW) is characterized by comprising the following steps of (1) obtaining an intermediate frequency signal of a multi-channel frequency modulation continuous wave millimeter wave radar (FMCW) system, (2) carrying out distance dimension FFT and phase extraction and unwrapping on a Chirp intermediate frequency signal channel by channel, and (3) carrying out phase extraction and unwrapping on the Chirp intermediate frequency signal channel by channel. (3) calculating signal energy of interested breathing and heartbeat frequency bands in the phase time sequence under all distances, and weighting amplitudes of all distance dimension FFT under all distances to realize accurate positioning of a human body target, and (4) regarding the phase time sequence under the accurate distance and the adjacent distance of each channel as potential multipath signals, and performing fusion enhancement on the signals to realize accurate positioning of the human body target. And (5) processing the enhanced phase time sequences of the channels on the basis of multivariate variational mode decomposition, separating and estimating respiratory signals and heartbeat signals of the human body, and calculating an average respiratory rate and an average heart rate in an observation time period.

The invention discloses a fractional frequency division frequency synthesizer with output signal phase synchronization and frequency modulation continuous wave functions, and the basic structure is a charge pump phase-locked loop. Comprising a phase frequency detector, a first charge pump, a second charge pump, a low-pass filter, a voltage-controlled oscillator, a first buffer, a second buffer, a two-frequency divider chain, an IQ undersampling circuit, a local oscillator generator, a programmable multimode frequency divider, a Delta-Sigma modulator (DSM), a first selector, a second selector, a third selector, a tracking phase accumulator, a numerical control oscillator, an accumulation phase difference register and an atan2 logic circuit. The device comprises a main phase control circuit, a phase adjusting circuit, an enabling control circuit, a waveform generator and a serial peripheral interface. The decimal frequency-division frequency synthesizer can be applied to a general-inductance integrated system, ensures that output signals provided by a plurality of decimal frequency-division frequency synthesizers are consistent in phase in a multi-channel radio frequency transceiving system adopting a multi-chip splicing mode, and can also be applied to the general-inductance integrated system as a sensing signal source; and the speed and the distance of an object can be quickly sensed by the high linearity and the quick chirp capability of an output signal. The decimal frequency division frequency synthesizer is applied to a linear frequency modulation continuous wave radar system, initial phase synchronization can be carried out firstly, then frequency continuous modulation is carried out, and measurement errors can be eliminated. In view of functional similarity of partial modules of the synchronous loop and the FMCW loop, such as a phase frequency detector, a charge pump, a voltage-controlled oscillator and the like, the modules can be shared, so that the power consumption and area cost of the system are remarkably reduced.

The invention discloses a chirp interval modulation backscatter communication method and a chirp interval modulation backscatter communication system based on variable-length scrambling codes, which mainly solve the problems of high power consumption of backscatter labels and high system deployment cost in the prior art. According to the scheme, a sending end sends an environment LoRa signal; the backscattering label modulates information to be sent to an environment LoRa signal in a time interval modulation mode, and modulates a variable-length scrambling code to an anchor symbol; a receiving end performs frequency shift compensation on the backscattering signal by adopting a frequency shift compensation method, demodulates the backscattering signal by combining a sliding window with a variable-length scrambling code, intercepts a backscattering signal sample through the sliding window, and performs de-spreading and fast Fourier transform (FFT) on the signal in the window; the position of an anchor symbol is determined by detecting the maximum value of an FFT peak value, information sent by the backscattering label is recovered from the position of the anchor symbol, and data demodulation is completed. On the premise of keeping demodulation reliability, the power consumption of the tag is effectively reduced, the deployment cost of a backscatter communication system is reduced, and the method can be used for ultra-low power consumption Internet of Things communication.

The invention discloses an ant colony optimization energy focusing cable insulation damage positioning method and device, and relates to the technical field of cable detection engineering, and the method comprises the steps: generating a Gaussian envelope linear frequency modulation chirp detection signal, injecting the detection signal into a to-be-detected cable, and collecting an incident signal and an echo signal containing a reflection component; constructing a parameterized time-frequency analysis kernel function family under a Cohen type time-frequency distribution framework, and searching and optimizing kernel parameters by using an ant colony optimization algorithm; and calculating the time frequency distribution and energy-time curve of the signal based on the energy focusing time frequency analysis kernel function obtained through optimization, extracting the arrival time corresponding to an energy peak value, and realizing cable insulation damage positioning according to the reflection time delay and the propagation wave velocity. According to the method, energy peak focusing and peak position stability are enhanced while cross terms are restrained, defect positioning precision and robustness are remarkably improved, and the method is suitable for engineering online detection and automatic implementation of cable insulation damage.

The invention discloses an intracranial SEEG electroencephalogram data analysis method and system based on artificial intelligence, and relates to the technical field of data analys.The method comprises the steps that original electroencephalogram signals are obtained, and electrode space coordinates and imaging information are synchronized; extracting robust features in a time-frequency domain through synchronous extrusion in combination with learnable chirp and multi-resolution attention; according to the electrode coordinates and the anatomical topology, topology sensing alignment is executed, and an anatomical function diagram is constructed; performing continuous time evolution modeling on a node state through a graph neural continuous dynamic structure, and introducing an energy conservation and event jump mechanism to realize focus transmission chain inference; estimating orientation information in different physiological contexts, and screening a stable direction as a prior constraint; and outputting a continuous risk curve according to propagation embedding, and generating a coverage-controllable confidence interval through online conformal calibration. Energy consistency, causal stability and space-time continuous modeling of SEEG signals can be realized, and the accuracy and interpretability of electroencephalogram focus recognition and clinical risk assessment are improved.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a transmitter node may determine a set of parameters for a waveform to be transmitted by the transmitter node, wherein the waveform is to use an allocated bandwidth that is larger than a sweeping bandwidth of a frequency modulated continuous wave (FMCW) chirp. The transmitter node may transmit the waveform according to the set of parameters. Numerous other aspects are described.

The invention belongs to the technical field of wireless communication, and particularly relates to a communication sensing integrated system based on non-orthogonal AFDM (Alternating Frequency Division Multiplexing). According to the system, a bandwidth compression factor is introduced into an AFDM framework to construct a non-orthogonal waveform, and controllable overlapping between chirp subcarriers is realized, so that the spectrum utilization rate is improved, and the robustness of the system under a high-speed dynamic channel is enhanced. And a receiving end realizes reliable information recovery through maximum likelihood detection, and processes echo signals in combination with a two-dimensional parameter estimation algorithm so as to realize high-precision sensing of the target distance and speed. The system has good anti-Doppler capability and perception precision performance, and is suitable for communication perception fusion application in a high-speed mobile scene.

The invention discloses a vehicle-mounted multi-radar system interference suppression method, system and platform based on frequency hopping frequency modulation continuous waves, and the method comprises the steps: arranging at least one front radar and four corner radars on a vehicle, and enabling the field angles of the radars to have an overlapping region; wherein the waveform transmitted by each radar consists of N linear frequency modulation continuous waves, and the duration of each chirp is T microseconds; the chirp starting frequency of each radar changes along with time, so that N1 chirp is greater than or equal to 1 and less than or equal to N when each radar passes through N1 chirp; the initial frequency is increased or decreased by a fixed step delta F, and the average frequency hopping step is delta F / N1; according to the system and the platform corresponding to the method, the chirp initial frequency is dynamically adjusted and the time delay is accurately controlled, so that the interference-free cooperative work among the multiple radars is realized, the distance resolution, the speed resolution and the signal-to-noise ratio are remarkably improved, and the system and the platform have the advantages that the interference-free cooperative work among the multiple radars is realized. And meanwhile, hardware design is simplified.

A system comprises a digitally programmable frequency chirp generator configured to generate a frequency chirp, an attenuator coupled to the digitally programmable frequency chirp generator and a directional device integrated into a cryogenic circuit configured to control superconducting qubits and coupled to the digitally programmable frequency chirp generator. The directional device comprises a main arbitrary waveform generator and an on-chip programmable self-interference canceller.

The invention discloses an aging gait detection method and system based on a millimeter wave radar, and the method comprises the following steps: S10: employing the millimeter wave radar to collect the data of the activities of a human body going up and down stairs; s20, performing Fourier transform on the activity data after sampling to obtain signal frequency spectrum and target distance information; wherein the continuous Chirp signals of which the intervals are fixed values are stored as row vectors, and receiving frequency responses of targets at different distances can be obtained by performing 1D-FFT on each row; performing fast Fourier transform on a plurality of Chirp signals of the same distance unit to obtain target speed information, namely a time-Doppler graph; and S30, constructing a YOLOv11 model, constructing a data set by the time-Doppler maps, carrying out classification training by using the YOLOv11 model, carrying out batch classification prediction on the new time-Doppler maps, and finally outputting the prediction accuracy.

The application discloses a kind of chirp modulation photo-thermal-optical spectrum resonance frequency and concentration synchronous measurement method and system, belong to photo-thermal-optical spectrum field, comprising: S1, generating chirp modulation signal driving laser, produces modulated laser beam;S2, the modulated laser beam is inducted after passing through gas to the surface of quartz tuning fork excitation photo-thermal-optical signal demodulation obtains first harmonic signal;S3, using lorentz line function fitting the first harmonic signal;S4, according to fitting result, the center resonance frequency position of quartz tuning fork is calculated;S5, whether the center resonance frequency position of the quartz tuning fork is located in the center of first harmonic signal;If not, adjust chirp modulation signal initial frequency repeats S1-S5, until the center resonance frequency position of quartz tuning fork is located in the center of first harmonic signal;S6, according to fitting result, response coefficient is calculated, and inversion obtains gas concentration information.The application can realize high-precision measurement of gas concentration and real-time correction of resonance frequency.

In an aspect, a network device may transmit one or more first sets of first chirp signals in a first bandwidth assigned to an allocated frequency range of the network device for data communication and sensing signals. The network device may transmit one or more second sets of second chirp signals in a second bandwidth of the allocated frequency range, wherein the second bandwidth is greater than the first bandwidth.

A radar-based target velocity estimation method, and an apparatus therefor are disclosed. The radar-based target velocity estimation method comprises the steps of: (a) transmitting a radar transmission chirp signal and receiving a reception chirp signal reflected from a target; (b) multiplying the reception chirp signal by the transmission chirp signal, removing a high-frequency component through a low-pass filter, and then performing sampling through an analog-to-digital converter (ADC), and differently applying sampling periods along a time axis so as to generate a virtual chirp signal; and (c) Fourier-transforming the virtual chirp signal, and estimating the distance and velocity of the target by using the Fourier transform result.

The application discloses a method for sidelobe suppression of single-bit quantization Chirp signal, and the main technical content of the method comprises sidelobe suppression of single-bit quantization Chirp signal based on a convolution window function. The technical content performs sidelobe suppression through the following steps: step S1, generating a Chirp echo signal; step S2, single-bit quantization of the Chirp signal; step S3, single-bit quantization of a Chirp signal matching filter and adding a convolution window; and step S4, pulse compression of the single-bit quantization Chirp signal. The application can achieve a good compromise between quantization order and pulse compression effect, single-bit quantization can reduce quantization complexity to the maximum extent, and the sidelobe suppression method based on the convolution window function can effectively solve the problem of the decrease of the main sidelobe ratio caused by single-bit quantization. For Chirp signals and other radar signals with large time-bandwidth product, the application can improve the pulse compression effect, improve the range resolution of the radar system, and has certain reference significance for improved design in radar engineering technology.

The application discloses a kind of unmanned aerial vehicle frequency hopping signal fast detection methods based on parallel Chirp-Z transformation on FPGA, belong to wireless communication signal processing field, the method includes: to the radio frequency signal of unmanned aerial vehicle is down-converted and high-speed analog-digital conversion, obtains digital signal stream;And input digital signal stream in FPGA;FPGA is executed based on Chirp-Z transformation spectrum refinement analysis, to generate high-resolution spectrum;Spectrum refinement analysis includes: to generate first intermediate result by executing premultiplied step;First intermediate result is carried out convolution operation, to generate second intermediate result;After multiplying step is executed, second pre-stored Chirp sequence is read from the on-chip memory, and the second pre-stored Chirp sequence is multiplied with the second intermediate result to generate the high-resolution spectrum.The application significantly improves the final accuracy and effectiveness of the whole signal intelligence analysis link.

The invention discloses a low-power-consumption magnetic field sensing and transmission integrated method based on a full-simulation framework, and the method comprises the steps: collecting a magnetic flux leakage signal through an orthogonally-deployed dual-channel TMR sensor in a sensing stage, and carrying out the parallel processing of two channels through simulation addition and a differential circuit; an analog voltage signal with the optimal amplitude is obtained through peak detection and analog comparison logic self-adaptive selection, meanwhile, a corresponding binary level is generated according to amplitude high-low mapping, and blind area elimination and coding are completed from a physical layer. In the transmission stage, a non-linear device is utilized to passively extract a difference frequency component from an external double-chirp excitation signal, and a stable clock is obtained through resonant filtering and normalization; and the optimal analog voltage signal output in the sensing stage is directly mixed and modulated with a clock, and a radio frequency switch is driven to realize passive backscattering transmission. And a receiving end completes synchronization based on a known upper chirp sequence, compresses a backscattering signal to a base band through de-chirp and down-conversion, and recovers a binary bit stream at a node side through resampling and self-adaptive threshold judgment.

The invention discloses a vehicle-mounted FMCW radar cognitive anti-interference method and device. The method comprises the following steps: acquiring an interference signal received by a target vehicle-mounted FMCW radar; performing frequency modulation slope estimation on the interference signal by using a fractional order Fourier transform algorithm to obtain an interference frequency modulation slope of the interference signal; based on a preset frequency modulation slope construction function and the interference frequency modulation slope, determining a frequency modulation slope of a target emission signal of the target vehicle-mounted FMCW radar; and performing interference suppression on an initial echo signal received by a pre-acquired target vehicle-mounted FMCW radar based on a target interference signal constructed on the basis of the interference frequency modulation slope to obtain a target echo signal. The method is used for effectively suppressing coherent interference and incoherent interference in a dense traffic scene. Fractional order Fourier transform is adopted to identify coherent interference and estimate the Chirp frequency modulation slope of incoherent interference, and the problems that in the prior art, vehicle-mounted radar mutual interference suppression is insufficient, especially coherent interference and long-duration incoherent interference suppression is insufficient, and the suppression effect robustness is poor are solved.

The invention relates to the technical field of ultrafast laser, and discloses a negative chirp management method and device of a laser and a medium. The method comprises the following steps: pre-processing a seed pulse, outputting the seed pulse through a mode-locked optical fiber oscillator, and primarily amplifying the seed pulse through a single-mode gain optical fiber; temperature tuning negative chirp introduction is carried out, a chirp fiber grating is packaged in a temperature tuning device, and the temperature of a semiconductor chilling plate is linearly increased within a preset range, so that the second-order dispersion amount of the chirp fiber grating is changed, and controllable negative chirp is introduced into a pulse; carrying out nonlinear amplification and spectrum broadening, inputting the pulse introduced with the negative chirp into a multimode gain fiber, injecting pumping energy into the multimode gain fiber, and broadening the pulse spectrum width to be greater than a preset width by utilizing the synergistic effect of self-phase modulation, dispersion and gain; pulse width compression is carried out, and the pulse after spectrum broadening is adjusted through a transmission-type grating pair compressor, so that the ultra-narrow pulse width is obtained.

A distance measuring device includes a first section including a first optical waveguide configured to convey a chirp signal, a light source that generates light for modulation by a modulator to generate the chirp signal, and a second section including logic circuitry that controls the light source. The first section and the second section are stacked. The distance measuring device further includes a first conductor that forms at least part of an electrical connection between the logic circuitry and the light source, and the first conductor penetrates the first section at a position that is spaced apart from the light source in a first direction.

The invention relates to a spread spectrum receiver and a test method. A method of characterizing a LoRa modulated signal or any such signal having multiple chirps as symbols. It foresees: sampling and storing the signal, determining the phase of at least one chirp in the signal, and determining a timing error and / or a frequency error based on the phase, the timing error being extracted by the height of the discontinuity jump in the phase at the cyclic shift position, and the frequency error being obtained by the slope of the phase. The method can be applied to a dedicated receiver for characterizing a LoRa transmitter.

The invention relates to a method, an apparatus, and an article of manufacture for mitigating interference in Doppler distance representations. An example apparatus includes interface circuitry (212) for receiving digital samples representing a chirp frame. The apparatus includes programmable circuitry (214) programmable by instructions to: determine, for a range Fourier transform (FT) representation of the chirp frame, a reconstructed chirp in the chirp frame that includes chirps of corrupted samples; determining a first Doppler range representation of the chirp frame based on the range FT representation, the range FT representation including the reconstructed chirp; and determining a second Doppler distance representation as an element-by-element minimum between the first Doppler distance representation and a third Doppler distance representation of the chirp frame, the third Doppler distance representation based on the digital samples including reconstructed samples that replace the corrupted samples of the chirp. Other examples are described.

The application relates to a two-step correlation-based chirp ultrasonic signal time-of-flight estimation method, and belongs to the method for measuring the time-of-flight of ultrasonic waves. The coarse correlation is used to obtain the non-accurate TOF of the chirp ultrasonic signal, and the fine correlation is used to obtain the accurate TOF of the chirp ultrasonic signal. The application has the advantages that the accurate time-of-flight TOF is obtained through two-step correlation calculation, the amount of calculation is effectively reduced due to the small amount of data participating in the correlation calculation, and a detection method with low calculation amount is provided for the application fields of distance measurement, multi-target tracking and positioning and other ultrasonic time-of-flight detection-based application fields.

The embodiment of the application provides a method, device and equipment for determining echo delay of a linear frequency modulation acoustic signal. The method is applied to the field of digital signal processing. Time-varying band-pass filtering is performed on an acquired acoustic signal, the filtered acoustic signal is subjected to short-time Fourier transform and logarithm is taken, and a logarithmic time-frequency spectrum is obtained. Peak information in the logarithmic time-frequency spectrum is extracted, and a frequency modulation line of a linear frequency modulation signal is fitted, and an initial frequency of the linear frequency modulation signal is obtained. The frequency modulation line of the linear frequency modulation signal and the peak information in the logarithmic time-frequency spectrum are used for signal reconstruction, the reconstructed signal is subjected to short-time Fourier transform and logarithm is taken, a reconstructed spectrum is obtained, and a difference spectrum is obtained by subtracting the reconstructed spectrum from the logarithmic time-frequency spectrum. Peak information of the difference spectrum is extracted, a frequency modulation line of an echo signal is fitted, and an initial frequency of the echo signal is obtained. The initial frequency difference between the linear frequency modulation signal and the echo signal is used to determine an echo delay amount. The method has strong anti-interference capability and improves the calculation precision of the echo delay amount.

A laser system for the generation of ultrashort optical pulses of light including an oscillator emitting low power and negatively chirped optical pulses with a spectral bandwidth W1, a dispersive connecting segment to maintain the sign of the chirp of the pulses of the oscillator, an optical amplifier for amplifying the optical light pulses and a negative group velocity dispersion segment for compensating phase contributions of the whole propagation process. During the propagation from the output of the oscillator to the end of the optical amplifier, the chirp of the light pulses will change once from negative to positive chirp. After a final compression stage ultrashort optical pulses can be generated.

The invention belongs to the field of bird sound noise reduction, and discloses a bird sound noise reduction method and system for adaptive sub-band and acoustic index consistency loss of bird sound production, and the method comprises the steps: S1, carrying out the superposition synthesis of a clean bird sound sample and a noise sample, and generating a training sample; s2, processing the training sample to obtain a frequency band feature tensor; s3, performing time dimension and frequency dimension feature fusion processing on the frequency band feature tensor to obtain a fusion feature; and S4, performing calculation based on the fusion features, and reconstructing a de-noised bird sound audio signal. The high signal-to-noise ratio improvement, the distortion rate reduction and the target bird chirp audibility improvement are realized in the complex field sound scene, the accuracy of subsequent automatic identification and acoustic index calculation can be remarkably improved, and the method has important application value for ecological monitoring, bird protection and habitat evaluation.

The invention discloses a vibration suppression rotary table swing arm for aspheric surface numerical control polishing and a sliding mode control method of the vibration suppression rotary table swing arm, relates to the field of aspheric surface numerical control polishing, and solves the problem that the vibration suppression efficiency is not high when an existing aspheric surface polishing rotary table swing arm rotates. The component is in a periodic bending form based on a chirp function in the length direction of the armed lever, rigidity and mass distribution are in gradient change, and a self-adaptive broadband vibration suppression band gap is formed. A tail end vibration signal is collected in real time through a sliding mode control method, a sliding mode surface function containing a dynamic modulation item is constructed, a control law is designed to drive a swing arm track to converge, and meanwhile vibration energy is induced to migrate to the optimal vibration suppression frequency band of a vibration suppression component. Through the synergistic effect of heterogeneous structure design and active control, the vibration suppression efficiency and trajectory tracking precision of the swing arm of the rotary table are improved, and the method is suitable for high-precision scenes such as aspherical numerical control polishing.

The application discloses a frequency modulation rate variable laser linear frequency modulation device and a frequency modulation method thereof. The device comprises a wideband tunable laser, a micro-optical lens, a beam splitter, an adjustable optical delay unbalanced MZ interferometer, a balanced photodetector, a phase discriminator, a loop filter, an up / down switch control circuit and an integrator. The adjustable optical delay unbalanced MZ interferometer comprises two couplers and an adjustable optical fiber delay line unit. According to the relationship between the linear frequency modulation light frequency and time of the upper and lower arms of the interferometer, when the delay amount of the adjustable optical fiber delay line unit changes, the frequency modulation rate of the output laser can be changed. The application changes the time delay of the light by using the adjustable optical fiber delay line, so that the frequency modulation rate can be changed.