11 results about "Instantaneous bandwidth" patented technology

The invention discloses a frequency domain-time frequency domain adaptive time-varying filtering method with human-computer interaction characteristics, which comprises the following steps: manually selecting reference data points according to the energy distribution of signals in a time frequency domain, and obtaining an instantaneous frequency curve of a component to be extracted through cubic spline interpolation fitting; based on the short-time Fourier transform energy matrix and the cumulative distribution function, the instantaneous transmission band width at each moment is calculated in a self-adaptive mode; taking the instantaneous frequency as a center frequency and the instantaneous bandwidth as a transmission band boundary, constructing an elliptical digital band-pass filter bank, and forming a self-adaptive time-varying filter; performing time-frequency domain filtering decomposition on the original signal, and performing inverse short-time Fourier transform reconstruction to obtain a pure component signal; order spectrum / envelope order spectrum analysis is carried out on the components, and gear fault features are extracted. The method gives consideration to time domain and frequency domain information, achieves one-time filtering decomposition, is high in calculation efficiency, is high in anti-noise performance, and is suitable for the fault diagnosis of equipment with complex non-stationary signal features.

The invention provides a broadband frequency hopping device based on high-orbital angular momentum Rydberg atoms. An atomic air chamber comprises the high-orbital angular momentum Rydberg atoms; the first reflecting mirror and the second reflecting mirror are respectively used for reflecting the detection light and the coupling light to the atom gas chamber so as to excite high-orbital angular momentum Rydberg atoms from a ground state to an excited state and pump the high-orbital angular momentum Rydberg atoms to a first Rydberg state; the first microwave generator, the second microwave generator and the third microwave generator are used for enabling high-orbital angular momentum Rydberg atoms to be transited to a second Rydberg state, a third Rydberg state and a fourth Rydberg state respectively; and the photoelectric detector is used for receiving the detection light passing through the atomic gas chamber. According to the invention, frequency hopping crossing 6 octaves can be realized, the frequency hopping speed is 60khops / s, and the frequency hopping point number is expanded under the limited instantaneous bandwidth by using the microwave frequency comb. The method has potential application value in the field of secret radio communication.

The invention discloses a software-defined radar full-link integrated signal processing method, and belongs to the technical field of radar signal processing. According to the method, a hierarchical decoupling universal hardware platform composed of an AD9361 universal radio frequency front end, a high-speed data transmission interface and an FPGA + GPU + CPU heterogeneous computing rear end is constructed, and software definition of full-link functions such as waveform generation, signal processing and synchronous control is achieved. According to the invention, a dual adaptive CFAR detection algorithm of distance dynamic window + clutter multi-algorithm switching is adopted, so that all clutter environments can be adapted; nanosecond coherent synchronization of multiple radar nodes is realized through a GPS taming clock, and UTC synchronization precision can reach + / -50ns; and multi-station MIMO cooperative detection is realized through software-based beam forming. According to the invention, the instantaneous bandwidth of the radar is improved from 5MHz to 56MHz, the signal processing delay is reduced from 6.8 microseconds to 1.2 microseconds, the false alarm rate is reduced from 10 to 10, the research and development period is shortened from 18-24 months to 6-12 months, and the hardware cost is reduced to 1 / 5-1 / 10 of that of a traditional scheme.

The invention discloses a microwave photon interference scheme with a self-interference elimination function for a synthetic aperture radar. The invention relates to the technical field of radars and the technical field of microwaves, and is mainly applied to microwave photon interference signal generation and self-interference cancellation. The method is shown in an attached drawing, and comprises a laser device LD, a double-parallel dual-drive Mach-Zehnder modulator DP-DDMZM, an electric delay line DL, an electric attenuator ATT and a photoelectric detector PD. A sub-modulator DDMZM1 of a dual-parallel dual-drive Mach-Zehnder modulator DP-DDMZM is used for eliminating a self-interference signal, and a periodic rectangular pulse signal input to a lower radio frequency port of a sub-modulator DDMZM2 is used for realizing periodic change of an optical carrier amplitude. Periodic change of an optical carrier phase is realized through a periodic rectangular pulse signal input to a bias voltage port of the main modulator MZM, and finally photoelectric conversion of an optical signal output by the DP-DDMZM is completed through the photoelectric detector PD, so that flexible and effective two-dimensional interference and elimination of a self-interference signal on a distance domain and an azimuth domain can be realized at the same time. The two-dimensional interference signal generation and self-interference cancellation functions are integrated, parameter tuning is flexible, the structure is simple, the real-time performance is good, the generated interference signal is high in frequency band, the instantaneous bandwidth is large, the working range is wide, and the radar electronic warfare requirement and development trend at present are met.

This invention discloses a signal processing method applicable to various signal characteristics, relating to the fields of communication and radar signal processing technology. By combining the construction of a multi-dimensional signal feature library with real-time spectrum sensing, this invention achieves rapid analysis and accurate characterization of deep-space radar signal characteristics. The feature library is generated based on unsupervised clustering of historical data, covering various signal templates such as transient impulses, periodic coherence, and steady-state noise. It not only provides rich prior knowledge references but also supports online sliding window incremental updates, ensuring that feature representation always conforms to actual environmental changes. The real-time spectrum sensing employs adaptive window time-frequency analysis, with the window length dynamically adjusted according to the signal's instantaneous bandwidth and local stationarity, effectively balancing the contradiction between frequency resolution and time resolution and overcoming the limitations of traditional fixed-window analysis in non-stationary scenarios.

The application discloses a large wideband phased array antenna electric axis and mechanical axis alignment method and system, and belongs to the technical field of phased array antennas. The method comprises the following steps: in the frequency slicing stage, the working frequency of the phased array antenna is equally divided into n slicing frequency points in the instantaneous bandwidth range; in the beam scanning and data acquisition stage, the amplitude data set of each slicing frequency point is collected; in the electric axis position extraction stage, the electric axis position is extracted from the amplitude data set of each slicing frequency point, and an electric axis position set is obtained; in the electric axis center calculation stage, the least square method is used to find the regional electric axis position set, which is used as the electric axis center position of the phased array antenna in the instantaneous bandwidth; and in the electric axis and mechanical axis alignment stage, the beam scanning instruction is set according to the electric axis center position, so that the electric axis and the mechanical axis of the phased array antenna are aligned. The application is not affected by the precision of artificial mechanical adjustment, and can achieve the alignment precision of the electric axis and the mechanical axis at the level of 0.01 degrees.

The application relates to a light-assisted super-octave ultra-wideband synthetic aperture radar system and belongs to the technical field of ultra-wideband synthetic aperture radar, solves the problem of the limitation of the instantaneous bandwidth of a traditional electronic system, and is characterized in that the system comprises a digital system, an intermediate frequency system and a radio frequency system, and is further characterized in that the system further comprises a photonic radio frequency front end; the photonic radio frequency front end is connected between the intermediate frequency system and the radio frequency system; a photonic-assisted frequency multiplication technology is adopted to multiply the input intermediate frequency LFM signal and mix the multiplied signal with a local oscillation signal to generate a super-octave ultra-wideband signal; a photonic-assisted dechirp technology is adopted to multiply a received echo signal reflected by a target scene with a reference signal to generate a dechirped target echo signal; the reference signal is a linearly amplified and spurious-free ultra-wideband signal of the super-octave ultra-wideband signal. The application breaks through the limitation of the instantaneous bandwidth of the traditional electronic system and provides a new technical means for a large-instantaneous-bandwidth SAR system.

The application relates to a multi-channel ultra-wideband undersampling instantaneous frequency measurement method, belonging to the technical field of wideband digital radars, and solving the problem of spectrum overlap of multiple signals; for a scheme of multiple channels with different time delays, phase frequency measurement is combined with the remainder theorem to demodulate the frequency of an input signal; for signals near f s / 2, phase frequency measurement is carried out through the time delay difference between different channels to solve the frequency band in a targeted manner; for signals near f s / 2, multi-rate sampling is realized through a time-sharing sampling method, threshold discrimination and parameter matching are carried out on the FFT frequency measurement result through the remainder theorem, and finally, the PDW signal is demodulated, the method does not need to provide a high-speed pseudo-random sequence, has hardware realizability, has the characteristics of small size, no need of channelization, low algorithm implementation complexity, strong robustness and strong demodulation capability compared with the prior art, and can realize high-precision undersampling frequency estimation of radar signals under the index of 0 to 18G instantaneous bandwidth.

This application provides a multi-model irregular wave height prediction method and system based on physical knowledge constraints and dynamic attention fusion. The prediction system includes a prediction unit and a training unit. The prediction unit includes a first prediction model that outputs a first wave height prediction result based on the instantaneous bandwidth sequence of wave height from multiple wave height segments in a historical wave height sequence; a second prediction model that outputs a second wave height prediction result based on the instantaneous bandwidth sequence of wave height corresponding to a backward reconstruction sequence of the historical wave height sequence at multiple time scales; a regression coefficient model for generating a dynamic regression coefficient combination; a combined output module for weighted combination and outputting the final wave height prediction result; and a training unit that trains the prediction unit using a total loss function that includes a conventional loss term and a physical knowledge constraint loss term. The technical solution of this application improves the prediction effect of wave height under extreme sea states by weighting multiple prediction models with frequency band information and subjecting the training process to physical knowledge constraints.

The application discloses a passive radar target echo simulation system, comprising: a radio frequency signal generator, a power division unit and an amplitude and phase control unit connected in sequence; a total control unit connected with the radio frequency signal generator and the amplitude and phase control unit; the total control unit is used for analyzing the received control command, obtaining the passive radar working parameters and target parameters, and converting the passive radar working parameters and target parameters into first control instructions and second control instructions; the radio frequency signal generator is used for generating a reference microwave signal according to the first control instructions; the power division unit is used for dividing the received reference microwave signal into N microwave signals; the amplitude and phase control unit is used for receiving the second control instructions, adjusting the output amplitude and output phase of the N microwave signals according to the second control instructions, and then outputting the N microwave signals after being combined, and the application solves the problems of small instantaneous bandwidth and low simulation precision of multi-target echo characteristics.

The invention provides a frequency-domain wide-open anti-interference interception method and device for solving the problems that the instantaneous bandwidth is large, time-frequency overlapping is serious, and weak signals are difficult to intercept in ultra-wideband signal receiving. A high repetition frequency optical pulse and wavelength-mode multiplexing optical sampling front end is utilized to realize full-band direct sampling under the driving of a single clock source, strict time alignment between spatial arrays is realized through a multi-dimensional multiplexing structure, and direction-of-arrival estimation deviation and beam pointing distortion caused by sampling asynchronization of a traditional multi-channel system are eliminated in a physical layer; on the basis, combined calculation of an orientation estimation algorithm, anti-interference beam forming, frequency band segmentation and a feature identification module is combined, and spatial domain suppression, frequency domain separation and target identification are completed in sequence. According to the method, the double bottlenecks of information loss caused by frequency-division time-division sampling of a traditional electronic system and single function and insufficient flexibility of a microwave photon system are broken through, and the interception probability and identification confidence of dense, overlapped and weak radiation sources can be remarkably improved.