232 results about "Spread spectrum" patented technology

The invention relates to the technical field of communication, in particular to a satellite communication anti-interference transmission method based on a frequency hopping and spread spectrum fusion algorithm. According to the method, interference power is collected at multiple nodes, multiple sub-carrier frequencies and multiple moments to construct an interference observation tensor, interference features are extracted through low-rank tensor decomposition, and interference of each sub-carrier frequency in a future frequency hopping time slot is predicted; calculating a signal to interference plus noise ratio and capacity according to predicted interference in combination with transmitting power and noise, constructing a utility function containing a service weight and a balance coefficient, and distributing working sub-carrier frequency to each satellite communication node under concurrency constraint to generate a frequency hopping sequence; a transmitting end performs channel coding, modulation and spectrum spreading on service data and transmits the service data according to a frequency hopping sequence, and a receiving end completes synchronization, de-spreading and decoding and performs weighting processing by utilizing predicted interference. The method improves the spectrum utilization rate and the interference suppression capability, and enhances the satellite communication reliability.

The invention discloses an encrypted communication system and method based on cognitive multi-carrier spread spectrum, and belongs to the field of covert communication. The encryption communication system comprises a transmitting device and a receiving device. The transmitting device comprises a data encryption module, a constellation encryption modulation module, a multi-carrier spread spectrum module, a frequency hopping module and a cognitive power distribution module. The receiving device comprises a band-pass filtering module, a de-hopping frequency module, a de-spreading module, a constellation decryption demodulation module, a data decryption module and a coherent combination module. The data encryption module is divided into an interleaving coding unit and a double-rule reversible cellular automaton encryption unit. The cognitive power distribution module continuously scans a wireless electromagnetic environment and carries out real-time spectrum analysis to give power spectrum density results sensed under all frequency hopping frequency sets. According to the invention, continuous detection and dynamic response to the spatial frequency spectrum state can be realized, and the communication concealment, the anti-interference performance and the resource utilization efficiency in a complex electromagnetic environment are remarkably improved by utilizing the frequency spectrum hole.

The invention discloses a carrier tracking method suitable for a multi-bit spread spectrum signal, and relates to the technical field of multi-bit spread spectrum, the carrier tracking method comprises the steps of coarse frequency offset correction, multi-bit spread spectrum, average phase estimation and delay phase correction.The carrier tracking method comprises the steps that firstly, a sliding DFT algorithm is adopted to estimate frequency offset, and a coarse frequency offset available correction signal is obtained; secondly, adaptively selecting the number of available windows according to historical data corresponding to the current signal-to-noise ratio; the method comprises the following steps: firstly obtaining a window intermediate point spread spectrum period, then extracting a carrier phase estimation value of the window intermediate point spread spectrum period, finally delaying a correlation value by the spread spectrum period to realize time sequence alignment and eliminate phase deviation, and finally obtaining information bits corresponding to each spread spectrum period by extracting and correcting a real part of the correlation value, matching a local sequence number and mapping. According to the method, the phase estimation precision under the low signal-to-noise ratio can be improved, parameter self-adaption to high and low dynamic scenes of a satellite is realized, the coherent judgment performance is improved, and the hardware complexity is reduced.

A measurement and control simulation device based on a measurement and control data transmission integrated system comprises an upper computer display control test module, a PC host module, a signal processing master controller module, an isolation DC / DC module, a down-conversion module, a filtering module, an isolator module and an outer end face interface module. The system has the characteristics of multiple modulation systems, a spread spectrum function, controllable output power, Doppler frequency change and the like, can be used for simulating a star chain control system link test in a ground test system, and fully improves the index assessment performance during system docking; meanwhile, the design of a down-conversion link meets the requirements for the strength and sensitivity of the received signal, the stability and accuracy of the radio-frequency signal after frequency conversion in a low-power injection state are remarkably improved, and a new scheme is provided for a high-frequency conversion mode. Besides, the display control module of the equipment has the functions of multiplexing, reconstruction, multi-data interaction and the like, so that multifunctional and multi-task full-system test coverage can be realized, the cost investment of test systems such as spacecrafts and the like is greatly reduced, and the multifunctional index test coverage efficiency is improved.

The invention discloses a chirp spread spectrum photon terahertz communication perception integrated system. The system comprises a coherent light source module used for generating two beams of coherent single-frequency optical carrier signals; the signal modulation module is used for generating a baseband chirp spread spectrum communication sensing integrated signal and modulating the signal to one beam to form a carrier signal; the integrated signal transmitting module is used for taking the other beam of single-frequency optical carrier signal as an optical local oscillator signal, and after the optical local oscillator signal is coupled with the carrier signal, a terahertz communication sensing integrated signal is generated and radiated through optical down-conversion; the communication receiving module is used for performing frequency conversion and demodulation on the received terahertz communication sensing integrated signal and recovering communication information in the signal; and the radar receiving module is used for performing de-chirp and target information estimation on the received terahertz communication sensing integrated signal. According to the system, the advantages of a photon terahertz architecture are fully exerted, and an ultra-wideband chirp spread spectrum integrated signal is generated, so that a communication sensing integrated system with high spread spectrum gain and high energy efficiency is realized.

The invention discloses a Ka-band broadband filtering antenna, which comprises a probe, a ground paving layer, and a first horizontal dielectric plate, a first radiation patch, a second horizontal dielectric plate and a second radiation patch which are arranged on the ground paving layer, and is characterized in that the first radiation patch is provided with a c-shaped groove, the c-shaped groove is internally provided with a circular groove, and the circular groove is internally provided with a pair of branches; one ends of the two branches are combined to form a combined end connected to the first radiation patch, and the other ends of the two branches are parallel and have a gap to form a parallel opening end; and the center of the second radiation patch is close to the combined end of the two branches on the first radiation patch and far away from the parallel opening ends of the two branches on the first radiation patch. According to the invention, through collaborative design of slotting and branch knot loading, a filtering structure is innovatively constructed. The core innovation lies in the collaborative design of the two filtering structures and the spread spectrum structure, and the filtering frequency domain and the passband width are remarkably improved. The method can be widely applied to the fields of base stations, national defense and military industry and the like.

Methods are generally described for inaudible orthogonal signal communication. An example method includes determining, based on an input message, a series of symbols, where each symbol from the series of symbols represents a numerical value, wherein each symbol from the series of symbols corresponds to a band-limited white noise tone orthogonal to each other band-limited white noise tone corresponding to each other symbol. The example method also includes generating a sub-token comprising each symbol from the series of symbols, where each symbol overlaps in time with at least one other symbol. The example method also includes modulating a carrier wave with the sub-token to produce a signal audio waveform, where the modulation uses a spread spectrum technique, and providing the signal audio waveform to a television device, where the television emits the signal audio waveform as a low-amplitude audio signal.

The invention discloses an outdoor power equipment temperature abnormity monitoring method, device and equipment, and the method comprises the steps: carrying out the calibration processing of power equipment temperature data collected based on a dynamic collection frequency through employing a preset calibration algorithm, and obtaining the calibration temperature data; performing temperature anomaly analysis according to the calibration temperature data based on the temperature threshold, the trend threshold, the mutation mechanism and the baseline standard, and generating an anomaly analysis data packet; sending the abnormal analysis data packet to a relay gateway according to a spread spectrum technology and a check retransmission mechanism, so that the relay gateway performs data aggregation and protocol conversion processing based on an abnormal priority to obtain a transmission data packet; and triggering different temperature early warning mechanisms through the cloud platform according to the abnormality level in the received transmission data packet to realize temperature abnormality early warning. The technical problems of lack of timeliness, accuracy and remote control capability of monitoring due to lack of timeliness, weak data acquisition anti-interference capability and easy loss in the data transmission process in the prior art can be solved.

The invention relates to an IRNSS navigation signal simulation generation method and system based on parameter compensation, and the method comprises the steps: receiving original signal data outputted by an IRNSS navigation receiver, and receiving a target machine position coordinate and a velocity vector; analyzing the navigation message to extract ephemeris parameters, and calculating the real-time position and velocity vector of the satellite; calculating a Doppler frequency compensation value and a pseudo code time delay compensation value; according to the pseudo code time delay compensation value and a preset target simulation coordinate, modifying a signal emission time field in the navigation message, generating a simulation navigation message frame, carrying out forward error correction coding processing, generating a coding symbol sequence, and carrying out modulo-two addition operation on the coding symbol sequence and a pre-generated PRN pseudo code sequence to obtain a baseband spread spectrum signal; generating an intermediate frequency carrier signal according to the Doppler frequency compensation value and the carrier phase; and modulating the baseband spread spectrum signal to the intermediate frequency carrier signal, and outputting an intermediate frequency analog signal. According to the invention, the concealment of signal simulation and the success rate of capturing the analog signal by the target receiver can be improved.

The invention discloses an electromagnetic compatibility integrated protection system for an electric driving system of an electric vehicle, which relates to the technical field of electromagnetic compatibility protection and comprises a multi-dimensional parameter synchronous sampling module for acquiring an operation condition characteristic sequence of a target electric driving system in a preset time window; the space-time diagram isomorphic prediction module outputs a predicted interference frequency domain feature vector corresponding to the current control period; the collaborative anti-interference resolving module is used for respectively calculating a carrier frequency band spread spectrum instruction aiming at a bottom microcontroller and a reverse compensation injection current aiming at an active filtering loop; and the bottom hardware reconstruction execution module is used for updating a carrier frequency register of a pulse width modulation generator in the target electric driving system according to the carrier frequency band spread spectrum instruction and synchronously controlling the active filtering loop to output the reverse compensation injection current. According to the invention, the accurate pre-judgment capability of electromagnetic interference of the electric driving system of the electric vehicle and the long-term stability of full-life-cycle electromagnetic compatibility protection are improved.

The invention relates to the technical field of low-power wide area network communication and information hiding, and discloses a LoRa-based covert communication method, which comprises the following steps of: at a transmitting end, generating a key-driven perturbation sequence according to covert information to be transmitted, constraining perturbation parameters through an undetectable controller, and transmitting the perturbation sequence to a receiving end; performing symbol-level perturbation modulation on the linear frequency modulation slope of the LoRa signal, and embedding a low-speed synchronous beacon in a preamble symbol counting tolerance range; at a receiving end, conventional data is demodulated through a standard LoRa receiving process, a frequency offset residual error, a phase residual error and a symbol fitting error after de-spreading are extracted in parallel, related detection is carried out by using a key consistent with a sending end, and hidden information is extracted from a residual error domain; the undetectability controller dynamically adjusts perturbation magnitude and embedding density based on a distribution difference metric. The objective of the invention is to solve the problem that communication reliability and hidden undetectability are difficult to guarantee at the same time in a LoRa system.

The invention relates to the technical field of wireless communication, in particular to an emergency LoRa communication method based on multi-band cooperation and dynamic resource modulation. The method comprises the following steps: S1, dynamically acquiring communication environment information, channel quality information and network load information; s2, dynamically analyzing and selecting an initial target spreading factor based on the information; s3, setting a preset factor optimization target by taking the minimum bit error rate as a target, and dynamically adjusting and obtaining a current optimal spreading factor; and S4, based on the current optimal spread spectrum factor, performing dynamic allocation of spectrum resources by adopting a dynamic channel allocation mechanism and a reinforcement learning algorithm of adaptive network load balance, and learning a network state in real time through the reinforcement learning algorithm so as to dynamically select an optimal channel allocation strategy to perform emergency communication. According to the method, communication parameters can be adaptively adjusted, the network efficiency and reliability are remarkably improved, the system capacity, the real-time performance and the robustness in a mobile scene are enhanced, and reliable communication guarantee is provided for rescue in an extreme environment.

The invention belongs to the technical field of EMI (Electro-Magnetic Interference) suppression, and relates to an EMI filtering method based on dual-frequency spread spectrum and dual-frequency recombination common-mode noise cancellation waveform, which comprises the following steps of: selecting a frequency as a composition frequency; enabling the EUT to work normally by taking a selected frequency as a switching PWM frequency, and obtaining common-mode noise amplitude data of multiple times of the frequency; acquiring a common-mode voltage amplitude, and calculating an amplitude transformation ratio and an amplitude of an injected offset waveform; acquiring a common-mode voltage amplitude, and calculating the phase of the injected offset waveform; injection offset waveform data is obtained through calculation, and the common-mode voltage is offset; according to the invention, common-mode noise is taken as a main scene, and common-mode suppression can be realized while the size is reduced.

This invention relates to a multi-mode communication release-response integrated time-synchronized underwater mooring system and method, and relates to the fields of underwater acoustic communication networks and underwater positioning and navigation technology. The purpose of this invention is to solve the problems of poor reusability of existing underwater mooring systems in complex and diverse application scenarios, the insynchrony of time among mooring nodes making it impossible to coordinate data aggregation or communication reporting tasks at precise times, resulting in single-function underwater mooring equipment, low resource utilization, and large reference time errors. The system includes multiple dual-master control mooring communication units and an external battery compartment, integrating spread spectrum communication, OFDM communication, multiple orthogonal response, atomic clock timekeeping, release control, and positioning functions; it achieves time synchronization and local timekeeping through 1PPS signals and GPRMC information or absolute time information; after deployment, each node completes multi-mode signal reception and response according to a preset mode, and serves as a positioning anchor point to achieve platform positioning through a long baseline positioning algorithm; after the task is completed, it is released and surfaced under control.

Systems, methods, and apparatus, including computer programs encoded on computer-readable media, for downhole fault detection in a well system are disclosed. A spread spectrum time domain reflectometry (SSTDR) apparatus of the well system may transmit an SSTDR signal downhole via a well electrical cable of the well system and receive a reflected SSTDR signal. The SSTDR apparatus may determine whether a downhole fault exists in the well electrical cable or in a well device based on a signal analysis of the reflected SSTDR signal and the transmitted SSTDR signal. The SSTDR apparatus may also use historical SSTDR data and a machine learning algorithm for downhole fault detection and analysis. When a downhole fault is detected, the SSTDR apparatus also may determine a type of the downhole fault and a location of the downhole fault, such as the depth downhole of the downhole fault.

The invention relates to a spread spectrum and time-digital conversion cooperative underwater communication measurement system and method, belongs to the technical field of underwater wireless optical communication, and solves the technical problems of limited communication rate and insufficient positioning precision in an underwater complex environment. The measurement system comprises a master-end underwater wireless optical communication machine and a slave-end underwater wireless optical communication machine, each of the master-end underwater wireless optical communication machine and the slave-end underwater wireless optical communication machine comprises an optical transmitting unit, an optical receiving unit, a signal processing unit, an upper computer and a shell. And the optical transmitting unit, the optical receiving unit and the upper computer are respectively connected with the signal processing unit. The optical transmitting unit, the optical receiving unit and the signal processing unit are arranged in the shell, and the upper computer is arranged outside the shell. The measurement method comprises the steps of system initialization and link establishment, communication and time service synchronization, distance measurement signal triggering and transmitting, and distance calculation and display. The method is used for underwater robot collaborative operation, ocean monitoring and deep sea detection.

This invention relates to a system for realizing bidirectional RF signal source output of a millimeter-wave vector network analyzer. The system includes a vector network analyzer main unit, a main unit port output channel, a rear panel output channel, and a signal switching and control unit. The vector network analyzer main unit has a built-in main RF signal source, and the RF signal output from the main RF signal source is output from the front test port of the vector network analyzer main unit. The rear panel output channel outputs the RF signal output from the main RF signal source from the rear auxiliary RF port of the vector network analyzer main unit. The system, method, apparatus, processor, and computer-readable storage medium of this invention for realizing bidirectional RF signal source output of a millimeter-wave vector network analyzer improve high-frequency measurement performance. By using the spread spectrum module as a remote test head closer to the DUT, it reduces the loss and error of long cables, increases testing flexibility, and enables switchable RF signal source output paths, meeting the needs of various testing scenarios.

Some implementations herein relate to a device that receives and processes multiple spread spectrum signals corresponding to multiple linear frequency modulated (LFM) signals, including multipath LFM signals having directly and indirectly received signal components. Based on the transmission times and transmission locations of the multiple spread spectrum signals and the multiple LFM signals, the device can estimate the location of the device, the time the device was at a location, the arrival times of the directly and indirectly received signal components, and the time difference of arrival between the arrival times of the directly and indirectly received signal components. Based on the transmission locations, the device location, and the time difference of arrival, the device can estimate a range to a surface relative to the device location.

The application provides a cable aging online monitoring method and device based on a spread spectrum time domain reflection method, which comprises the following steps: establishing a frequency-variable distribution parameter model based on the physical structure of a cable, performing background noise spectrum scanning on the cable to identify a spectrum hole, and taking the spectrum hole as a working frequency band of a detection signal; generating a detection signal matched with the working frequency band, and injecting the detection signal into a live cable; collecting echo signals of the cable, performing adaptive signal decomposition on the echo signals to obtain purified echoes, performing cross-correlation operation on the purified echoes and the detection signal, and extracting reflection response features; performing phase dispersion compensation on the reflection response features to obtain dispersion-corrected reflection responses; extracting multi-dimensional feature vectors of the dispersion-corrected reflection responses, inputting the multi-dimensional feature vectors into a physical information neural network, and inversely obtaining insulation aging quantitative indexes and cable aging grades of each position of the cable.

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 application discloses a new energy base-oriented information sensing and transmission system and relates to the technical field of power Internet of Things.The system comprises an edge convergence gateway and a plurality of sensing terminal nodes.The edge convergence gateway constructs a dynamic topology according to micro-meteorological vector data, selects a cluster head node at the upstream of physical field propagation, calculates and issues a theoretical envelope delay parameter, and the sensing terminal node uses a perturbation signal modulated by an orthogonal pseudo-random spread spectrum code and the parameter to complete phase alignment, uses the parameter to perform space-time compensation and predicted waveform construction on received cluster head reference data, calculates a numerical residual error between a local waveform and a predicted waveform, quantitatively encodes sparse residual errors to generate an upper report data packet.The application eliminates the physical field propagation delay caused by spatial distribution, effectively reduces the differential data energy, and solves the problem of real-time and efficient transmission of high-frequency waveforms under limited bandwidth.

The invention relates to a PMFFFT spread spectrum signal capturing method based on multi-threshold fusion judgment. The method comprises the following steps of: storing serial time domain I / Q data and two groups of spreading code sequences as one group into a BRAM according to the correlation point number of a partially matched filter to obtain a plurality of groups of signal search pairs; and searching all code phases of I / Q data in the BRAM by taking the code phase search precision as a step, and respectively executing partial matching filtering operation on signal search pairs corresponding to the local target pseudo code sequence and the noise pseudo code sequence to obtain corresponding operation results. And performing FFT (Fast Fourier Transform) on the operation result to obtain a search result. And executing multi-threshold fusion judgment on a search result, and capturing a spread spectrum signal according to a judgment result. By adopting the method, the false alarm probability of a low-sensitivity receiver in a strong signal or interference signal environment can be effectively reduced, and the satellite signal capturing performance of the receiver is improved.

The invention provides a velocity deblurring method based on multi-band radar Doppler power spectrum joint constraint, which comprises the following steps: acquiring at least two different-band radar Doppler power spectrum data, the maximum non-blurring velocity of a second-band radar being smaller than that of a first-band radar; eliminating invalid distance library data through noise bottom estimation and effective spectrum threshold judgment; deblurring the first wave band radar to obtain a reference speed profile; establishing a cross-band data corresponding relation through space-time matching; determining the fuzzy type of the second band radar library by library; performing spectral domain reconstruction on the power spectrum according to partial folding or complete folding, constructing a candidate spread spectrum, and selecting an optimal folding frequency and a deblurring speed by utilizing cross-band consistency constraint and vertical continuity joint judgment; and outputting the deblurring speed profile and the quality identifier of each wave band. According to the invention, the technical problems of poor speed deblurring accuracy and low robustness in a complex meteorological scene and misjudgment caused by the fact that a single-band method depends on single continuity constraint or average speed are solved.

A spread spectrum switching power conversion circuit, a clock generation circuit and a clock generation method. The spread spectrum switching power conversion circuit includes: a power stage circuit including an inductor and a power switch for switching the power switch to perform power conversion according to a switching signal with spread spectrum; a variable frequency oscillator for generating a spread spectrum clock signal according to a spread spectrum control signal; a spread spectrum control circuit for generating the spread spectrum control signal according to a first clock signal and a second clock signal; and a pulse width modulation circuit for generating the switching signal according to a feedback signal based on the spread spectrum clock signal; wherein the spread spectrum control circuit samples and operates a first periodic waveform with periodicity and a first random waveform with randomness to generate the spread spectrum control signal. The first random waveform is generated according to the first clock signal, and the first periodic waveform is generated according to the second clock signal.

The invention relates to the technical field of integrated circuits, and discloses a double-feedback loop spread spectrum phase-locked loop circuit. The circuit comprises a clock generation phase-locked loop and a spread spectrum signal generation loop. The clock loop generates and locks the center frequency. The spread spectrum loop adopts a time length locking principle, a fixed reference time T4 is set through a digital parameter SSR, and a feedback counter is used for measuring an output clock period to obtain a feedback time T6. The error between the T4 and the T6 is compared, the error is converted into a triangular wave modulation voltage through a charge pump and a modulation signal generator, and after superposition, a voltage-controlled oscillator is controlled to realize frequency modulation. The spread spectrum depth is directly and accurately controlled through pure digital parameters, the problems that modulation precision of a traditional scheme depends on analog gain, is limited by loop bandwidth and is complex in circuit design are solved, high-precision, programmable and stable spread spectrum clock generation is achieved, system electromagnetic interference is remarkably reduced, and the method is suitable for a high-integration-level communication chip.

The invention discloses a service-adaptive satellite-borne non-uniform multicarrier demodulation device, and belongs to the field of digital signal processing. The method comprises the following steps of: firstly, performing orthogonal down-conversion and resampling filtering processing on a digital intermediate frequency signal sampled by an ADC (Analog to Digital Converter), processing the digital intermediate frequency signal by a non-uniform channelization splitter, and then serially outputting the digital intermediate frequency signal to a spread spectrum ratio self-adaptive variable burst capturer according to fixed quadruple sampling to capture a leading head and identify the spread spectrum ratio; the method comprises the following steps: completing symbol synchronization and de-spreading processing on an input signal according to a spread spectrum ratio, then completing carrier coarse synchronization and pattern word identification, completing modulation mode identification and carrier synchronization according to a pattern word, performing channel decoding through a multi-mode decoder to recover to an information bit stream, and outputting the information bit stream. And the information bit stream is sent to a service frame recombination processor for search identification and recombination splicing, and output is carried out after whole-frame CRC check is carried out. The method has the advantages of flexibility in use, low resource occupation and capability of realizing adaptive demodulation of variable-rate, multi-modulation-mode and multi-coding-mode service transmission signals without parameter configuration.

The present disclosure provides a signal generation method, device and communication system, relating to the technical field of wireless communication and terminal. The method comprises: generating a first binary keying signal OOK waveform based on a low-power wake-up LP-WUS signal, replacing part of the waveform of each period in the first OOK waveform with a constant modulus sequence to obtain a target waveform, the constant modulus sequence being a group of sequences with the same modulus but different phases. According to the embodiment of the present disclosure, the first OOK waveform generated based on the LP-WUS signal can be scattered, the frequency diversity gain of the LP-WUS signal is improved, a similar spread spectrum effect is formed, so that the signal can still have good performance when passing through a frequency selective fading channel (such as TDL-C), so as to improve the detection accuracy and detection efficiency of the LP-WUS signal, and further improve the synchronization of NR reception and reduce energy loss.

The application discloses a clock spread spectrum method, system and device, and relates to the technical field of electronic circuits.The method comprises the following steps: obtaining the frequency of an input clock, the modulation amplitude of clock spread spectrum and the modulation frequency of clock spread spectrum; calculating the target value of the frequency amplitude of a spread spectrum signal based on the frequency of the input clock and the modulation amplitude of clock spread spectrum; generating a spread spectrum signal with a frequency amplitude gradually changing every preset period according to the modulation frequency of clock spread spectrum and a preset rule; the preset rule is a rule determined according to a preset period and the target value of the frequency amplitude of the spread spectrum signal; the preset period is a value determined based on the frequency of the input clock; synthesizing the frequency of the input clock and the frequency of the spread spectrum signal to obtain a frequency control code; and generating an output clock after spread spectrum according to the frequency control code.The application can avoid the output clock losing lock due to frequency mutation caused by clock spread spectrum, and improves the robustness of the system.