3831 results about "Baseband" patented technology

Disclosed is a suppression method for a multipath signal of an image mode based on correlation peaks of a satellite baseband signal, including the steps of: constructing a real-world direct-multipath two-dimensional color image mode data set; and building a multipath suppression model of a deep learning network based on a long-short term memory (LSTM) and a self-attention mechanism module, and training the model. In the present disclosure, a satellite signal can be quickly captured without losing the sensitivity of the captured signal, and a Beidou satellite baseband signal can be captured from a signal recorded in the real world, which enables the model to learn complex signal patterns, improving the accuracy and robustness of multipath signal suppression in urban complex scenes.

The invention relates to the field of heart rate monitoring, and discloses a millimeter wave radar breath and heart rate synchronous monitoring method and system, and the method comprises the steps: transmitting a linear frequency modulation continuous wave signal according to a millimeter wave radar, and collecting original echo data reflected by a target region; baseband signal demodulation and phase information extraction are carried out on the original echo data to obtain original phase time sequence data, and the original phase time sequence data comprise thoracic cavity micro-motion features; and according to a Butterworth band-pass filter, preprocessing the original phase time sequence data through human body physiological signal frequency band characteristics to obtain a breathing frequency band signal and a heart rate frequency band signal. According to the method, the apnea event triggering threshold value and the arrhythmia early warning index are updated in real time through Kalman filtering and extended Kalman filtering, so that the monitoring system can dynamically adjust the health parameters, which means that the monitoring system can be optimized in real time and the abnormal health event can be accurately responded in different physiological states.

The invention discloses an adaptive modulation anti-multipath unmanned aerial vehicle swarm communication method and system based on MIMO-OFDM, and relates to the technical field of wireless communication, and the method comprises the steps: receiving a down-conversion baseband; synchronization and compensation are carried out; removing a cyclic prefix and carrying out fast Fourier transform; estimating a channel and noise on the training and pilot frequency, and correcting a common phase; performing frequency domain equalization and soft decision, forward error correction and cyclic redundancy check according to the estimation to obtain a control parameter, decoding a payload according to the control parameter, and performing statistics to form a link quality indication; modulating coding, bandwidth and spatial mode, configuring mapping, power and weight, and packaging physical layer protocol data; carrier sensing conflict avoiding sending, confirmation and retry are adopted to generate media access statistics; and the routing selects the next-hop multi-hop forwarding according to the transmission quality, and performs end-to-end statistics and recharge. Through cooperation of hierarchical synchronization and phase correction with cyclic prefix and FFT, crosstalk is suppressed, channel noise scale optimization soft decision is robust, data decoupling is controlled, and end-to-end availability is improved through multi-hop self-healing recharge.

The invention discloses an improved satellite navigation authorization signal real-time estimation device, which comprises a public signal tracking module used for tracking a public pseudo code of a satellite navigation signal in real time and outputting the public pseudo code of the satellite signal, a navigation message, baseband data after carrier stripping and a chip synchronization signal; the authorization signal purification module is used for estimating a pseudo code of the authorization signal in real time; and the public signal tracking module is connected with the authorization signal purification module. According to the method, the navigation message and the public pseudo code information of each code period are demodulated firstly, and then pseudo code estimation of M baseband constellations is improved into pseudo code estimation of M / 2 baseband constellations under the assistance of the navigation message and the public pseudo code, so that the bit error rate of authorized pseudo code estimation is reduced, and the accuracy of pseudo code estimation is improved. And the high gain requirement of the satellite navigation authorization signal estimation device on the receiving antenna is reduced.

The invention relates to the technical field of high-frequency signal modulation, and discloses a high-frequency carrier synchronization signal modulation system. A carrier distortion compensation module of the system constructs a model based on a historical transmission data set, captures a phase jitter parameter, a spectrum leakage component and a modulation pulse sequence of a transmitting end carrier in real time, and outputs a reconstructed baseband parameter; the multi-dimensional distortion analysis module compares the reconstructed baseband parameter with a receiving end demodulation baseband parameter through composite difference detection, and generates a channel-level distortion coefficient tensor; the topological positioning network module is used for positioning signal out-of-step physical nodes and generating a probability distribution thermodynamic diagram by combining impedance characteristics of transmission nodes and signal path delay information; and the adaptive modulation strategy module starts a multi-band carrier injection mode for the high-probability out-of-step nodes according to the abnormal probability gradient of the thermodynamic diagram, and applies a phase disturbance test to adjacent transmission links. The system can improve the adaptability and accuracy of high-frequency carrier signal synchronous modulation.

The invention belongs to the technical field of low-orbit satellite communication, and discloses a satellite system for jointly improving measurement and control data transmission and communication application efficiency. A control unit is responsible for completing satellite calendar attitude calculation of satellite broadcast, analyzing a satellite working mode switching instruction according to ground station information stored by a storage unit, and then sending the instruction to each module unit; the two baseband processing units both support on-orbit reconstruction and loading, wherein the baseband processing unit A is used for completing measurement and control signal processing or user wide beam access signal processing; the baseband processing unit B is used for completing communication service signal processing or data transmission signal processing; the two up-conversion units respectively carry out up-conversion processing on a service link signal and a measurement and control link signal in the signal processing module, and the two down-conversion units respectively receive signals of the phased array transceiver antenna and the wide beam transceiver antenna and complete down-conversion processing. The measurement and control link can support a satellite measurement and control function and a communication wide beam access function in a time-sharing manner.

The invention provides a baseband radio frequency signal data feedback processing method based on vector modulation, and the method comprises the steps: firstly receiving a baseband signal data set transmitted by a target radio frequency link in a preset frequency band, and the baseband signal data set comprises a plurality of signal frame original modulation parameters and corresponding radio frequency feedback signal waveforms; calculating a feedback error index composed of a phase offset, an amplitude distortion factor and a spectrum leakage factor according to a radio frequency feedback signal waveform, quantifying a modulation error, carrying out time-frequency domain conjoint analysis on the feedback signal waveform, extracting an error feature vector, inputting the error feature vector into a pre-training model for cross-frame correlation learning, and carrying out the correlation learning; according to the method, a dynamic adjustment parameter sequence containing a time sequence dependency relationship is generated, and finally a closed-loop feedback control link is constructed based on the dynamic adjustment parameter sequence and original modulation parameters, so that precise processing and optimal control of baseband radio frequency signals are realized, and the signal transmission performance is effectively improved.

The invention discloses a multi-mode SAR interference method and device, and belongs to the field of radar electronic countermeasure, and the method comprises the steps: respectively calculating a product matrix of each interference mode in an interference preparation stage; after entering a reconnaissance stage, intercepting a first section of receiving signal, judging whether the first section of receiving signal is an SAR signal or not, estimating parameters of the SAR signal, and extracting one frame of complete SAR pulse signal as a reference signal; intercepting a second section of receiving signal, and judging whether to enter an interference stage or not according to the PRF; after entering the interference stage, receiving a part of SAR pulse signals and recovering the part of SAR pulse signals into complete SAR pulse signals; multiplying the complete SAR pulse signal by the product matrix to obtain a baseband interference signal; and modulating the baseband interference signal into a radio frequency interference signal and transmitting the radio frequency interference signal. According to the invention, multiple modes of interference such as false target implantation, pseudo radio frequency interference and scattered wave interference can be realized, the interference signal modulation complexity is low, and the requirement of the interference device for the isolation of the transceiving antenna is low.

A global navigation satellite system (GNSS) spoofing detection and classification technique is provided. An optimization problem is formulated at the baseband correlator domain by using an optimization algorithm such as the Least Absolute Shrinkage and Selection Operator (LASSO) algorithm, for example. A model of correlator tap outputs of the intended received signal is created to form a dictionary of pre-computed waveform functions (e.g., triangle-like-shaped functions). Sparse signal processing can be leveraged to choose a decomposition of pre-computed waveform functions from the dictionary. The optimal solution of this minimization problem can discriminate the presence of a potential spoofing attack peak by observing the decomposition of two different code-phase values (authentic and spoofed) in a sparse vector output. A threshold can be used to mitigate false alarms. Furthermore, a variation of the minimization problem can be provided that enhances the dictionary to a higher resolution.

The invention relates to the technical field of ground resistance detection, in particular to a single-core cable ground resistance detection method capable of resisting strong power frequency interference. High-frequency signals are injected in a non-contact mode through a coupling type capacitor clamp, background voltage and current signals are collected firstly, and injection frequency far away from power frequency and harmonic waves is selected through Fourier analysis; cancelling background noise by adopting a normalized least mean square adaptive filter to generate an enhanced signal; the signal is down-converted to a base band through digital quadrature demodulation, a Kalman filter estimates the amplitude and the phase in real time, and the state and noise parameters are periodically calibrated through a compressed sensing algorithm; and finally, loop impedance is calculated according to the voltage and current amplitudes and the phase difference to obtain grounding resistance. The method has the advantages of being non-contact, high in safety, strong in anti-interference capability, high in measurement precision and the like, and is suitable for monitoring the grounding state of the cable in a complex electromagnetic environment.

The invention discloses a phased array computing terminal real-time beam forming and interference reduction method, which comprises the following steps of: 1, acquiring an observation signal by an observation target, calculating an independent narrow-band beam former for each sub-band channel for a channelized frequency domain baseband signal, and further realizing frequency domain real-time beam forming on all baseband signals at the same time, based on the dynamic change of the propagation environment, the beam forming weight is updated, the beam shape and direction are adjusted, and the maximum signal-to-noise ratio beam forming is realized; and 2, effective interference reduction is realized by adopting spatial filtering in phased array calculation terminal equipment, a spatial filter is constructed in combination with a subspace projection method, identification and elimination of interference signals are realized through calculation and characteristic decomposition of a covariance matrix, and finally filtered signal data are obtained. According to the method, a large number of independent tasks in matrix operation can be efficiently processed, so that the calculation time is remarkably shortened, and the observation capability of a system and the adaptability of an application scene are improved.

The invention relates to the technical field of data fusion transmission, and provides a heterogeneous data fusion transmission method and system for airborne multimode satellite communication. Acquiring real-time communication parameters including a dynamic spectrum occupancy state, a polarization direction difference and a hidden transmission demand level; generating a dynamic frequency hopping control instruction based on the time-varying characteristic of the dynamic spectrum occupancy state, driving carrier switching and reserving a spectrum isolation area between adjacent carriers; performing orthogonal polarization diversity analysis on the carrier switching result based on the polarization direction difference, suppressing cross polarization interference and outputting multiple paths of baseband signals; calling a preset waveform parameter library according to the hidden demand level to determine a modulation parameter, and loading the baseband signal to the asymmetric phase subcarrier to generate a hidden modulation waveform; and fusing the frequency hopping instruction and the hidden modulation waveform to generate a cooperative modulation instruction, and controlling the radio frequency unit to realize anti-interference fusion transmission. According to the technical scheme provided by the invention, the anti-interference capability of fusion transmission of multi-mode satellite data in a dynamic spectrum environment is improved.

The invention discloses a tracking processing method for a baseband signal of a receiver, which comprises the following steps of: firstly, performing frequency correction through a frequency-locked loop, and performing phase correction through a phase-locked loop to realize accurate synchronization of carrier frequency and phase; then bit synchronization processing and incoherent integration are carried out, and the output signal-to-noise ratio of the loop and the measurement precision of the code phase are improved; and finally, the local pseudo-random code generator generates a local pseudo-random code, then the local pseudo-random code generator outputs three paths of pseudo-random codes which are mutually delayed by half a chip, namely a lead code, a real-time code and a lagging code, correlation values of the three paths of pseudo-random codes are obtained, a code phase error is obtained by calculating the correlation value difference of the lead code and the lagging code, and the local pseudo-random code is obtained. And after the code phase error is processed by a loop filter, an adjustment amount of a digital control oscillator is generated, so that the phase of the local pseudo-random code is adjusted. According to the invention, continuous adjustment of the digital control oscillator of the local carrier and the pseudo-random code is realized, so that correct navigation data information is demodulated for positioning calculation.

The invention discloses a network communication method and device suitable for a space-based distributed operating system, and the method comprises the steps: a satellite gateway node obtains a network layer data packet transmitted by an edge computing node, carries out the processing and packaging of the network layer data packet according to a data link layer protocol in a CCSDS protocol system, and transmits the network layer data packet to a ground station through a baseband and a radio frequency device; and after acquiring the data link layer data packet, the node, connected with the baseband equipment, of the ground station processes the data packet step by step according to a corresponding data link layer protocol and removes a data link layer packet header until an internal network layer data packet is acquired, and sends the internal network layer data packet to a corresponding control node. Establishing a communication tunnel between an edge computing node and a control node in the space-based distributed operating system; and the control node transmits the network layer data packet to the edge computing node through the communication tunnel by using the same communication line. According to the invention, the process running at the edge computing node and the control node can carry out network communication without any adaptation.

An adaptive modular multimodal communication and computing panel includes a multilayer stack with a protective layer transmissive in selected bands, a reconfigurable communication layer operable in phased array, reflectarray, hybrid phased reflector, free space optical, or quantum modes, and electronics with heterogeneous processors. A multi scale interconnect and input and output fabric couples electrical, radio frequency, guided optical, and free space optical domains through interfaces including electro optic transduction and RF or baseband conversion. The fabric may implement programmable true time delay, resonators, and comb referenced timing. A management system coordinates beamforming, sensing, routing, calibration, workload placement, and security. Panels tessellate and connect by electrical, radio frequency, and fiber optic interfaces, supporting hot swappable modules, blind mate connectors, robotic servicing, and anti tamper features. Power and thermal subsystems harvest, store, regulate, and dissipate energy. The architecture scales from chip level modules to vehicle, airborne, maritime, orbital, and deployable systems.

The invention discloses a reliable data transmission method for a narrowband satellite internet of things. The method comprises the following steps: defining a reverse data frame format; link state monitoring and quantification: continuously or periodically monitoring a quality index representing a link of the satellite Internet of Things terminal; continuously or periodically monitoring the uplink state of the satellite Internet of Things terminal by using a terminal link state evaluation module of the satellite master station baseband system; link state grading: dividing the current link state into a plurality of predefined state grades; identifying the transmission rate of the satellite Internet of Things terminal; constructing a self-adaptive confirmation window strategy: a sending end of the satellite Internet of Things terminal uses a confirmation window with a dynamic window size; the number of data packets confirmed by the transmitted ACK / NACK message, namely the window size, is dynamically adjusted according to the currently sensed link state and the identified terminal transmission rate; the performance of the whole system is improved.

The invention provides an OFDM signal receiving and processing system and method suitable for an NAVDAT system. According to the method, the characteristics that NAVDAT system signals have synchronous headers, pilot frequencies and the like are fully considered, firstly, the synchronous headers are used for carrying out correlation operation on received data to search a frame starting point, and a signal frame to be demodulated and decoded is obtained in combination with a constant false alarm detection algorithm; and subsequently, carrying out symbol synchronization to determine the FFT window position. Secondly, in combination with a discrete pilot signal, estimating an integral multiple frequency offset error, namely coarse synchronization, and further realizing estimation of a decimal multiple frequency offset error, namely fine synchronization, so as to realize frequency synchronization. And then, channel estimation is carried out by using the pilot signal and adopting a least square method to obtain the channel frequency response of the pilot, the frequency response of the complete signal is obtained through interpolation, and the rough estimation result is further processed through the designed RCAFCN network to obtain accurate channel estimation, so that the original OFDM signal is recovered. And finally, extracting a data part in the OFDM signal according to a frame structure, realizing soft demodulation through a log-likelihood ratio mode, decoding data of a signaling part by using a polarization code, and decoding data of a service part by using a low-density parity check code, thereby realizing complete demodulation and decoding. The method provided by the invention can effectively reduce inter-symbol interference and inter-carrier interference existing in OFDM signals, compensate channel distortion, reduce noise influence, improve decoding precision, improve communication quality, realize optimization of NAVDAT system baseband processing, and guarantee sailing safety of ships on the sea by combining with an existing marine broadcast system.

The invention provides an anti-interference sound signal data extraction method based on energy data perception, and belongs to the technical field of underwater sound signal processing, and the method comprises the steps: carrying out the A / D sampling and digital orthogonal demodulation of a received sound signal, and obtaining a baseband signal; performing low-pass filtering and downsampling on the baseband signal to obtain a preprocessed signal; performing matched filtering on the pre-processed signal by using a reference signal; the key improvement lies in that a local energy estimation function of a preprocessed signal is calculated, and normalization processing is carried out on a matched filtering result and the energy estimation function to obtain a normalized detection signal. The method effectively suppresses the shielding effect of a strong interference signal on a weak target signal under a non-orthogonal reference signal and a strong near-end and weak far-end scene, remarkably reduces the misrecognition probability, and improves the accuracy and reliability of the extraction of a long-distance and low-signal-to-noise-ratio target beacon signal in a complex underwater acoustic environment. The method is suitable for underwater navigation, positioning and communication systems.

The invention relates to an unmanned aerial vehicle RemoteID signal detection, demodulation and analysis system and method, an upper computer sends a task instruction to a central control module through a network module to carry out radio frequency data acquisition, the central control module controls a radio frequency receiving module to acquire an electromagnetic wave signal of a specified frequency band in an airspace environment, and the electromagnetic wave signal is transmitted to the central control module; carrying out low-noise amplification and filtering processing on the electromagnetic wave signal of the specified frequency band; iQ data acquisition is carried out, wherein an intermediate frequency acquisition module acquires signals and carries out frequency mixing, filtering and AD sampling processing; inputting the acquired IQ data into a baseband data processing module, and performing analysis processing through the baseband data processing module based on an unmanned aerial vehicle RemoteID signal detection algorithm, an unmanned aerial vehicle RemoteID signal demodulation algorithm and an unmanned aerial vehicle RemoteID signal analysis algorithm; and an operation result of the baseband signal processing module is transmitted to an upper computer for display through the network transmission module. Remote and non-standard frequency band Remote ID signal supervision and analysis can be realized, the system stability is high, and the algorithm detection, demodulation and analysis accuracy is high.

The invention discloses an arbitrary digital signal synthesis method and system. The method comprises the following steps: analyzing a target parameter of a digital signal to be synthesized; generating a first multi-path baseband waveform by using a digital direct frequency synthesizer according to a modulation rate parameter in the target parameters, and reading pre-stored noise data to generate a second multi-path baseband waveform; selecting a plurality of appointed baseband waveforms, and modulating the plurality of baseband waveforms by using carrier frequency and bandwidth parameters in target parameters to obtain a plurality of instantaneous frequency curves; and integrating the multiple instantaneous frequency curves to obtain a phase stepping curve of each path, selecting a phase modulation curve according to a phase modulation type in the target parameters, and performing digital direct frequency synthesis on the phase stepping curve and the phase modulation curve of each path to generate multiple parallel digital synthesis signals. According to the invention, the synthesis process of the digital signals of different modulation types is uniformly decomposed, so that the coupling degree of the module and the complexity of the system are greatly reduced, and meanwhile, the resource consumption is reduced.

The invention discloses a high-throughput satellite communication terminal system, which comprises a radio frequency channel unit, a signal processing unit, a terminal processing unit, a power supply management unit and an anti-electromagnetic interference module, and is characterized in that the radio frequency channel unit carries an agile device and a power amplifier and is used for realizing bidirectional conversion between a baseband signal and a radio frequency signal; communication frequencies of a Ka frequency band, a valley value of 5GHz and a peak value of 40GHz are supported, a zero intermediate frequency receiver structure is adopted, image frequency interference is eliminated through one-time frequency conversion to a baseband, and a high-integration design that a radio frequency signal directly enters a frequency mixer after passing through an antenna, a radio frequency filter and a low-noise amplifier is realized. According to the high-throughput satellite communication terminal system, the coverage problem of traditional communication in a blind area of a power grid is solved, safe, efficient and stable transmission of power data is realized, the emergency communication capability and the equipment environment adaptability are remarkably improved, and key technical support is provided for constructing global visual monitoring and intelligent scheduling of the digital power grid.

The invention relates to the technical field of capacity evaluation and redistribution, in particular to a 4G baseband processing capacity dynamic expansion method and system, which comprises the following steps: acquiring a scheduling cycle connection request and rate, generating a load identifier in combination with a processing utilization rate trend, cross-positioning a high-density target block matching activation path, and carrying out dynamic expansion on the 4G baseband processing capacity. Extracting a frequency band request frequency and a flow analysis bearing level, processing interference intensity sorting frequency resources, screening frequency points, and splicing to generate a path configuration result. According to the invention, the connection request number and the data transmission rate in the 4G baseband scheduling period are collected to accurately identify the increased load section, the potential load rising pressure can be perceived in advance, the target block is crossly positioned according to the connection request position distribution and the data aggregation degree, and the processing resources are accurately bound to the high-demand path. The precision of spectrum resource scheduling is enhanced through priority ordering, and communication quality guarantee and continuous supply of processing resources in a high-concurrency access scene are supported.

The invention discloses a method for switching between a first communication mode and a second communication mode, and the method comprises the steps: determining a dual-mode phase difference between a first mode baseband signal and a second mode parameter based on the first mode baseband signal and the second mode parameter; generating an interleaved phase coding sequence in response to the dual-mode phase difference; pre-modulating the first mode signal in parallel before switching by using the coding sequence, and generating a pre-activated second mode virtual signal; switching from the first mode to the second mode is executed based on a parallel fusion phase track generated after the phases of the two preprocessed signals are subjected to time-varying weighted fusion. According to the method, a smooth switching track is constructed through parallel phase preview and phase domain fusion, phase continuity and frequency stability in the switching process are ensured, switching time delay and the data error rate are remarkably reduced, and the communication service quality of the heterogeneous network is improved.

The invention relates to the technical field of coal mine telecommunication, and discloses a coal mine underground integrated private network coverage system based on a 5G communication and AR double-transmitting selective-receiving technology, an efficient transmission and baseband processing network is constructed by taking a macro base station as a core on the ground and matching with PTN equipment and a BBU, a 5G micro base station and an RRU are deployed under the ground for a complex environment, and low-loss signal coverage is realized through optical fibers. The AR double-transmitting selective-receiving module ensures that underground data are not lost and have no error through redundant coding and double-link transmission; the edge computing module sinks data processing to the underground, reduces transmission delay and optimizes resource allocation; and the system monitoring and interference suppression unit monitors the operation state in real time, performs multi-stage alarm and resists multipath effect and electromagnetic interference, and finally realizes integration of communication above and under the well, reliability of data transmission, high efficiency of resource utilization and stability of system operation, thereby providing solid communication support for safety production, equipment management and control and personnel scheduling under the coal mine.

The present application belongs to the technical field of wireless communications and radar systems. Disclosed are a dual-band fusion and multiplexing frequency source, chips, a radio-frequency transceiver, a system, and a device. The system comprises: a full-function millimeter-wave CMOS 4+1 phased array chip, which is connected to an antenna end, and is used for realizing signal processing and frequency conversion between a millimeter-wave signal and a C-band intermediate-frequency signal, performing phase control and gain adjustment on the millimeter-wave signal, and providing an internal frequency source and a calibration function; a C-band front end, which is connected to the antenna end, and is used for receiving or transmitting a C-band signal; a C-band / intermediate-frequency transceiver multiplexing chip, which is used for performing frequency conversion between a C-band or intermediate-frequency signal and a baseband signal in a multiplexing manner, and performing signal processing and gain control on the C-band intermediate-frequency signal; a dual-band fusion and multiplexing frequency source, which is used for providing a local oscillator signal; and an all-digital control logic circuit, which is used for providing a control instruction. The present application improves the efficiency and performance of dual-band joint communications.

The invention provides a GNSS deception jamming joint detection system and method, and relates to the technical field of GNSS. GNSS navigation signals are received and processed through a baseband signal processing module, and advanced, instant and lagged related function values of an I path and a Q path are generated; a signal layer index unit calculates a moving variance of a code phase difference based on the correlation function value to generate a signal layer index; the information layer index unit calculates a code carrier difference value based on the pseudo-range, the carrier frequency and the integral carrier phase to generate an information layer index; and the spoofing detection module performs data fusion on the signal layer index and the information layer index to generate a joint detection index, and judges a spoofing state through a threshold value. The distortion of an IQ code correlation value integral signal is captured through a signal layer, and on the other hand, the inconsistency of a deception signal carrier, a pseudo-range relative measurement value and a real signal is captured through an information layer, so that the technical effect of rapid complementary detection of the signal layer and the information layer on deception interference is realized.

A frequency offset estimation method for a satellite VDES system, characterized in that it includes the following steps: step 1, down-converting a carrier-containing signal output by an AD to move the signal to a baseband; step 2, performing CIC down-sampling processing on the down-converted signal to reduce the data rate to 4 times the symbol rate; step 3: performing frame synchronization processing on the CIC down-sampled signal to find the position of the frame header; step 4: performing coarse frequency offset estimation and compensation on the signal after the frame synchronization processing; step 5: performing Mpart fine frequency offset estimation on the signal after the coarse frequency offset compensation.

The invention relates to a digital pre-distortion method and system based on a hierarchical iterative neural network, and belongs to the field of digital pre-distortion of power amplifiers. According to the method, the pre-distortion process is decoupled into two stages of off-line generalization training and on-line specialization optimization. In the offline stage, a mixed data set containing multiple modulation modes and bandwidths is adopted to train an offline neural network, and a basic model with high generalization ability is constructed; in the online stage, aiming at a signal with a specific modulation mode and bandwidth, a single configuration data set is utilized to train an online neural network, and the accurate compensation capability of the model on a real-time input signal is enhanced. In practical application, a baseband signal is firstly subjected to targeted preprocessing through the online neural network, then is subjected to deep optimization through the offline neural network, and finally is input into the power amplifier PA. According to the method, through a generalization-specialization double-layer structure, the dynamic response capability and compensation precision of a digital pre-distortion system to a complex signal environment are remarkably improved.

The invention relates to the technical field of wireless communication, in particular to a multimode chip core architecture system realized based on a software radio technology, which comprises an anti-interference module used for executing real-time optimization on a multi-system compatible baseband data stream and calling a dynamic compensation mechanism based on dynamic frequency shift characteristics in an environment characteristic data set, adjusting a local frequency source and a channel equalization parameter through multi-stage compensation operation to obtain an anti-interference enhanced data stream; and the packaging module is used for packaging the anti-interference enhanced data stream and the positioning data into a time-hopping pulse-direct sequence code division multiple access fusion frame structure and sending the fusion frame structure through a radio frequency unit. Through an ASIC and SDR hybrid architecture and a four-level hierarchical design, a multi-system communication function is integrated, and the hardware efficiency is improved and the power consumption is reduced.

The invention discloses a differential signal synthesis circuit of a double-IQ mixer, which belongs to the technical field of radio frequency microwave testing and comprises two single-ended IQ mixing modules, a 180-degree phase shift module and an in-phase combination module or a power division module. The single-ended IQ frequency mixing module is used for up-converting the single-ended IQ baseband signal to radio frequency or down-converting the radio frequency signal to the single-ended IQ baseband signal; the 180-degree phase shift module is used for converting an input signal into two paths of signals with a phase difference of 180 degrees; and the power division module is used for converting the radio frequency input signal into two paths of signals with the phase difference of 0 degree. According to the invention, the IQ mixer with a differential structure is constructed, so that the microwave band of the IQ mixer is comprehensively improved in the index aspects of local oscillator leakage, even-order component suppression, common-mode interference suppression, signal-to-noise ratio and the like; according to the invention, single-ended IQ mixers with various types and complete frequency bands can be constructed into a differential structure form, and signal indexes in numerous application scenes are improved.