33 results about "Filter bandwidth" patented technology

The invention discloses a power supply real-time compensation technology and application based on digital signal processing, and relates to the technical field of power electronics, and the power supply real-time compensation technology comprises a split-phase parallel processing architecture: a three-phase independently configured DSP core, each core integration comprises a real-time harmonic detection module, a dynamic sliding window FFT-RT algorithm is adopted, and the window length is adjustable in a set range; the bandwidth of the self-adaptive variable parameter filter can be dynamically adjusted in a set range; the FPGA coprocessor is specially used for PWM generation; an input stage of the harmonic prediction and decomposition module is synchronously acquired by a multi-source sensor; the processing layer comprises an improved VMD decomposition unit and a variational mode decomposition order; the edge prediction network is used for deploying a lightweight LSTM model, embedding a DSP core and predicting a harmonic spectrum in a future short period; and the multi-target dynamic optimization layer is used for setting a dynamic weight distributor and performing real-time adjustment according to the load sudden change rate. According to the invention, through split-phase parallel architecture, harmonic prediction and dynamic optimization, the response speed, multi-target cooperation and reliability improvement in the field of power supply real-time compensation are realized.

The invention relates to the technical field of data processing, and discloses a signal intra-pulse modulation pattern recognition method and system, and the method comprises the steps: receiving a radar pulse signal; performing short-time Fourier transform on the radar pulse signal; in the time-frequency matrix, calculating an energy distribution gradient of each time point along a frequency axis; according to the energy distribution gradient of each time point, identifying gradient abrupt change points; determining a filtering bandwidth boundary based on the gradient catastrophe point by adopting a negative feedback regulation mechanism of bandwidth and signal-to-noise ratio; based on the filtering bandwidth boundary, performing bandwidth filtering on the radar pulse signal; calculating an instantaneous frequency, a first-order differential frequency and a second-order differential frequency of the filtered signal through Hilbert transform, and forming a feature vector; predicting a cluster number range through a long and short term memory neural network according to the feature vectors; according to the feature vector, through a K-Means clustering algorithm, carrying out clustering analysis in a clustering number range; and outputting a modulation style label according to a clustering analysis result.

The invention discloses cross-scene reusable multi-modal physiological intelligent monitoring equipment and system. The equipment comprises a multi-modal physiological acquisition sensing array, an acquisition control module, a placement detection module, a self-adaptive parameter adjustment module and a signal processing module. The multi-modal physiological acquisition sensing array comprises an ambient light sensor, a photoelectric volume pulse wave sensor, a temperature sensor, a sensing electrode, a pressurizing electrode, a sound collector, an inertial measurement unit and the like; the placement detection module is used for calculating the comprehensive confidence coefficient of the current physiological electric signal belonging to each physiological signal type for each signal acquired by the multi-modal physiological acquisition sensing array, so as to judge the physiological signal type to which the physiological electric signal belongs; the adaptive parameter adjusting module is used for generating a sampling rate, an amplification factor, a filtering bandwidth and an ADC bit depth corresponding to the current physiological signal type; and the signal processing module is used for carrying out signal processing according to the parameters of the self-adaptive parameter adjusting module. Multi-modal physiological signal monitoring can be realized by adopting one set of equipment.

The invention discloses a millimeter wave detection anti-noise performance improvement method and a millimeter wave detection anti-noise performance improvement system, relates to the technical field of anti-noise performance improvement, and is used for solving the problem of defect discrimination sensitivity and positioning precision reduction caused by insufficient identification accuracy of sound wave or radar detection in a high-humidity and high-noise tunnel environment. Target echo power is calculated by transmitting millimeter wave signals and receiving tunnel wall surface echoes, noise is collected and noise power is extracted, a gain adjustment coefficient is obtained based on the ratio of the two echoes, target signals are amplified, and a judgment threshold value is generated by combining wall surface material reflection characteristics so as to identify structural defects and generate abnormal information. The method comprises the following steps: adjusting the bandwidth of a receiving filter to obtain an optimized echo signal, analyzing the type, position and severity of a defect, extracting a multi-path echo delay difference to realize accurate positioning, and finally judging whether to generate early warning information or not by combining the delay difference and abnormal information, thereby improving the detection precision and response speed of the system under noise interference.

The application provides a terahertz wave tunable waveguide type narrow-band filter and a manufacturing method thereof. The filter comprises a cavity with a rectangular structure, the upper surface and the lower surface of the cavity are low-loss metal surfaces with a periodic groove structure, a wedge-shaped protruding area is arranged in the middle of the cavity, and the two side walls are flat. The application has the advantages of simple structure, small size, low cost, easy integration, high Q value, small insertion loss, small transmission loss, and the like. The tuning of the output center frequency of the filter can be realized by adjusting the transverse position of the filter. The filter bandwidth and the transmissivity of the filter can be changed by changing the number of waveguide periods, the distance between the upper and lower flat plates, and the groove depth.

The invention discloses a non-invasive troponin monitoring system, which comprises a signal acquisition module, a filtering processing module, a feature extraction module, a clustering result generation module, a clustering result generation module, a clustering result generation module, a clustering result generation module, a clustering result generation module, a clustering result generation module and a clustering result generation module, wherein the signal acquisition module collects bio-electricity signals and the like to generate a data set, and the filtering processing module calculates a signal-to-noise ratio and adjusts filter bandwidth to output filtering signals. The data fusion module synchronizes the electrocardiogram period to integrate the feature vector, and the calibration output module monitors the environment change and generates a calibrated feature vector. According to the non-invasive troponin monitoring system, an original data set is generated by collecting multi-dimensional signals of a human body and environmental parameters. A dynamic filtering technology is utilized to optimize a signal-to-noise ratio, accurately extract time domain and frequency domain features and perform clustering analysis, an electrocardiogram period is synchronously analyzed to realize data fusion, multi-dimensional feature vectors are generated, calibration is performed in combination with environment monitoring data, interference is effectively eliminated, and high precision and stability of a troponin monitoring result are improved.

The invention discloses a wavelength division isolation anti-interference method and system for a radio frequency optical network front return signal, and the method comprises the steps: introducing an interference monitoring system which represents the quality of a radio frequency signal and the power optical noise at the same time, and constructing a wavelength interference matrix of the normalized interference intensity between any wavelength channel pairs according to the interference monitoring system; carrying out topology analysis based on the matrix, calculating the interference degree and automatically dividing interference clusters of high-interference channels to realize global perception and quantitative description of a common-fiber link interference relationship; target wavelength configuration parameters of the central wavelength, the wavelength interval, the guard band width and the optical filter bandwidth of each channel are adaptively determined by using the interference matrix and the interference cluster result, and differential widening and frequency shift are performed on the channels in the interference cluster; and finally, by controlling the adjustable light source and the adjustable optical filter, the wavelength division configuration is dynamically reconstructed along with the interference environment. Therefore, in an ARoF + PoF common-fiber transmission scene, both the anti-interference capability of the radio frequency signal and the frequency spectrum utilization rate of the optical fiber can be considered.

The utility model provides a weft self-adaptive detection device for a weft accumulator. The weft self-adaptive detection device comprises a photoelectric transmitting and receiving module, a primary filtering module, a secondary filtering module, a weft threshold signal judging and adjusting module and an electronic control module, the photoelectric emitting and receiving module detects weft yarns and sends weft yarn detection signals to the primary filtering module and the electronic control module; the first-stage filtering module comprises a first multi-stage filtering circuit, and the first multi-stage filtering circuit is provided with a bandwidth adjusting unit; the electronic control module is connected with the bandwidth adjusting unit to adjust the filtering bandwidth of the first-stage filtering module; the secondary filtering module comprises a second multi-order filtering circuit, and the second multi-order filtering circuit is provided with a gain adjusting unit; the electronic control module is connected with the gain adjusting unit to adjust the gain of the secondary filtering module; the weft yarn threshold signal judging and adjusting module comprises a hysteresis comparison circuit, and the hysteresis comparison circuit is provided with a threshold adjusting unit; the electronic control module is connected with the threshold adjusting unit to adjust hysteresis threshold voltage.

The invention discloses a speed smoothing filtering method and system based on self-adaptive PI filtering, and solves the problems that in the prior art, when a Beidou / GNSS chip is used for navigation positioning, PVT is used for solving the speed, the filtering effect is poor, errors are large, and the navigation precision is low. The method comprises the steps that the original speed and speed variance of PVT solving at the current moment are obtained; calculating a speed difference value between the current moment and the previous moment, and judging a current motion state according to the speed difference value; adaptively adjusting the bandwidth of an adaptive PI filter according to the speed variance and the current motion state; and calculating a P coefficient and an I coefficient of the PI filter by using the adjusted bandwidth, and carrying out smooth filtering on the original speed to obtain a filtered speed. The bandwidth of the filter is adaptively adjusted according to the speed acceleration and deceleration conditions and the speed variance, effective smooth filtering of the PVT resolving speed is realized, and the navigation precision and reliability are improved.

A method for a wake-up transmitter comprises generating a wakeup signal (WUS) from a digital WUS sequence having an information symbol rate and a corresponding information symbol bandwidth, and transmitting the WUS over a frequency range having a signal bandwidth, wherein the signal bandwidth is larger than twice the information symbol rate, and wherein any frequency interval comprised in the frequency range conveys the digital WUS sequence when a width of the frequency interval is at least the information symbol bandwidth. A corresponding method for a wake-up receiver comprises receiving the WUS over the frequency range, and filtering the received WUS through a filter having a filter bandwidth for passing the information symbol bandwidth of the received WUS. Corresponding apparatuses, wake-up transmitter, wake-up receiver, communication device and computer program product are also disclosed.

The application discloses a rolling mill gearbox fault feature extraction method based on adaptive order analysis, wherein according to a gear order bandwidth, a gear vibration component low-pass filter cutoff frequency is calculated, a bearing vibration component band-pass filter center frequency is searched in a high-frequency spectrum peak, and a band-pass filter bandwidth is calculated; a gear vibration component is obtained through low-pass filtering, and a bearing vibration component is obtained through band-pass filtering and envelope demodulation; angular domain resampled signals are averaged, gear sideband amplitude and modulation ratio are taken as features to identify gear faults, and the ratio of a bearing fault feature amplitude to a rotation frequency amplitude is taken as a feature to identify bearing faults; according to the vibration performance of gear and bearing faults, the method designs feature indexes, has clear physical meaning, can eliminate the influence of working condition changes and noise components, and realizes accurate identification of rolling mill gearbox faults.

This invention discloses a DPSK receiver for adapting to the defect of undesirable carrier frequency variation over time in the presence of a transmitter. The aim of providing an apparatus and method for adapting the receiver to transmitter defects is thus achieved. The frequency offset estimation unit includes a first phase estimation unit, a second phase estimation unit, and a clean / dirty selector, wherein a first phase error estimate e is output. dirty (k) The first phase estimation unit includes a first frequency offset estimation low-pass filter, the bandwidth of which is wider than the bandwidth of the second frequency offset estimation low-pass filter in the second phase estimation unit. The second phase estimation unit outputs a second phase error estimate e. clean (k), the dirty / clean selector is configured to compare the ratio of the second phase error estimate to the first phase error estimate with a threshold T and output a binary comparison result c(k). The demodulation reference estimation unit includes a first filter and a second filter, wherein the filter bandwidth of the first filter, which is part of the “dirty” reception path of the receiver, is wider than the filter bandwidth of the second filter, which is part of the “clean” reception path of the receiver. If the ratio of the second phase error estimate to the first phase error estimate is lower than the threshold T, the “clean” reception path is used to output the received information bits; otherwise, the “dirty” reception path is used.

The invention discloses a rolling bearing fault sound feature extraction method based on anti-noise Hough index guided optimal demodulation. The method comprises the following steps: collecting a sound signal during operation of rotating mechanical equipment through a sound sensor; determining a preset filtering bandwidth and a center frequency sequence; respectively carrying out band-pass filtering on the sound signal according to the filtering bandwidth and the center frequency sequence; calculating an anti-noise Hough index of each filtering signal to obtain a corresponding sequence; outputting the filtering signal corresponding to the maximum anti-noise Hough index as a target filtering signal; performing element-by-element adaptive sparse processing on the target filtering signal; demodulating the signal after the sparse processing by using an enhanced frequency weighted energy operator; and performing square envelope spectrum analysis on the demodulated signal to realize extraction of each fault characteristic frequency of the rolling bearing and recognition of a bearing fault mode. According to the method, the weak fault characteristic frequency of the rolling bearing can be adaptively and accurately extracted based on the non-contact acoustic measurement signal with a lower signal-to-noise ratio.

Embodiments of the present disclosure relate to systems, methods, apparatuses, and computer program products that align filter configurations between a device and a network. A method can include transmitting capability information to a network element. The method can also include receiving a radio resource configuration from the network element, the radio resource configuration including parameters for support of frequency arrangement and dynamic analog filter bandwidth switching determined from a local oscillator, and at least one parameter range. The method can further include maintaining a current local oscillator arrangement and analog filter configuration, or switching to a new local oscillator arrangement and analog filter bandwidth configuration, based on the radio resource configuration.

This application discloses a vibration protection method for equipment. To achieve vibration protection of the target equipment, a first signal is acquired, the real-time rotational speed of the target equipment is determined using the first signal, and a filtering bandwidth is determined based on the real-time rotational speed and the quality factor of a filter. The second signal is then filtered using this filtering bandwidth to obtain a filtered signal, i.e., a third signal. This filtering method ensures that the fundamental frequency component is retained as much as possible while removing the harmonic components. Furthermore, the third signal is resampled to obtain a fourth signal, the spectral resolution of which is higher than that of the third signal. This resampling method ensures that the fundamental frequency energy leakage is minimized, thereby maximizing the retention of the fundamental frequency vibration value of the fourth signal after frequency domain processing. This reduces the risk of false alarms and malfunctions when vibration protection is performed based on this fundamental frequency vibration value.

The embodiment of the invention discloses a signal processing method and system. The method is applied to a transmitting end, and comprises the following steps: acquiring a baseband signal to be transmitted, and determining a filter bandwidth of a channel where the baseband signal is located; determining the bandwidth of the pseudo-random sequence generated by the pseudo-random sequence generator based on the filter bandwidth; performing spread spectrum processing on the baseband signal based on the bandwidth of the pseudo-random sequence, and transmitting the radio frequency signal after the spread spectrum processing; wherein the bandwidth of the radio frequency signal after the spread spectrum processing is equal to the bandwidth of the filter. According to the technical scheme, the bandwidth of the pseudo-random sequence generated by the pseudo-random sequence generator can be determined through the bandwidth of the filter, and spectrum spreading processing is carried out on the baseband signal through the bandwidth of the pseudo-random sequence, so that the bandwidth of the baseband signal is expanded to be the same as the bandwidth of the filter; therefore, all useful signals of the baseband signals can pass through the filter, and useless out-of-band signals are just out of the band of the filter and can be filtered out, so that the signals can be better filtered.

The invention discloses a terminal general processing resource allocation architecture suitable for multi-system satellite communication waveforms. The architecture comprises intermediate frequency preprocessing resource evaluation, baseband processing resource evaluation, protocol processing resource evaluation and internal and external interface resource evaluation. And allocating a filtering bandwidth, a receiving level, an analog transceiving channel, a baseband processing resource, a protocol processing resource and an internal and external interface resource. Through intermediate frequency preprocessing resource evaluation, baseband processing resource evaluation, protocol processing resource evaluation and internal and external interface resource evaluation, a terminal product developed based on the method can support switching operation of various satellite communication system waveforms, the number of terminals is reduced, and the development and maintenance cost of the terminal product in the whole life cycle is reduced; and hardware resource configuration and maintenance support equipment are reduced, and the use and maintenance support pressure is reduced.

A microwave photon frequency-hopping transmission and reception system comprises a dual-band, dual-frequency cascaded optical frequency comb module, a transmission carrier generation and signal modulation module, a radio frequency transmission module, an orthogonal optical sampling clock generation module, an electro-optical sampling and orthogonal demultiplexing module, a radio frequency reception module, an optoelectronic conversion and digital processing module, and a synchronization and control module. In the frequency-hopping transmission portion, the communication signal is loaded onto the optical carrier via carrier-suppressed single-sideband modulation. The beat frequency of the optical carrier and the optical comb teeth selected by the optical switch generates an RF transmission signal carrying the communication signal. Rapid switching of the optical switch enables rapid, flexible, and wide-range switching of the transmission carrier frequency. In the frequency-hopping reception portion, the optical comb teeth are selected by the optical switch to generate an orthogonal optical sampling clock. Rapid switching of the optical switch enables rapid, flexible, and wide-range switching of the center frequency of the receiving passband. Flexible configuration of the frequency-hopping reception passband bandwidth is achieved by varying the filter bandwidth.

The invention discloses an automobile active noise reduction method and device, a storage medium and a computer program product, and the method comprises the steps: calculating the frequency of each order of an engine according to an engine rotating speed message, and constructing a sine signal and a cosine signal; based on a notch FxLMS algorithm, the amplitudes of the sinusoidal signal and the cosine signal are adjusted by using the signal collected by the error microphone so as to realize preliminary noise reduction; the method comprises the following steps: filtering a signal collected by an error microphone, selecting a filter bandwidth containing a filtering output signal of an engine order noise frequency, identifying an AR2 parameter by using an LS or RLS method, solving an error signal frequency and a peak value thereof according to the parameter, and when the frequency is in a frequency offset range and the peak value is relatively high, determining that frequency offset occurs and adjusting the frequency of a system reference signal. And noise reduction is realized. According to the method, the frequency offset can be accurately estimated, and the problem that the noise reduction effect becomes poor due to frequency synthesis deviation in automobile active noise control is solved.

This application discloses a wavelength division multiplexing (WDM) isolation anti-interference method and system for front-back signals in radio frequency (RF) optical networks. The method includes: introducing an interference monitoring system that simultaneously characterizes RF signal quality and power optical noise, and constructing a wavelength interference matrix based on this matrix to represent the normalized interference intensity between arbitrary wavelength channel pairs; performing topology analysis based on this matrix to calculate the interference degree and automatically classify high-interference channel interference clusters, achieving global perception and quantitative characterization of interference relationships in co-fiber links; using the interference matrix and interference cluster results, adaptively determining the target wavelength configuration parameters for the center wavelength, wavelength spacing, guard band width, and optical filter bandwidth of each channel, and implementing differentiated widening and frequency shifting of channels within the interference clusters; finally, by controlling tunable light sources and tunable optical filters, the WDM configuration is dynamically reconstructed according to the interference environment. Therefore, in ARoF+PoF co-fiber transmission scenarios, both RF signal anti-interference capability and fiber optic spectrum utilization can be balanced.

The application provides a filter bandwidth selection method and device for a Raman-fluorescence laser radar. The method provided by the application comprises the following steps: using a biological optical model to solve the attenuation contribution of pure water and chlorophyll components in a water body to a laser signal, and obtaining water optical parameters; constructing a laser radar signal simulation model based on the water optical parameters; including background light noise into the laser radar signal simulation model to form a complete received signal model; taking the ratio of a target channel exclusive signal to the complete received signal as the target signal ratio of filter bandwidth selection; determining a signal intensity rule; determining a target signal ratio rule; setting a signal intensity lower limit and a target signal ratio lower limit based on the signal intensity rule and the target signal ratio rule, screening out a filter bandwidth range that meets the requirements of both lower limits, and determining the maximum bandwidth in the filter bandwidth range as the optimal filter bandwidth.

The invention discloses an angular spectrum diffraction method based on dynamic acquisition of effective information of an object field spectrum, and the method comprises the steps: dynamically extracting the effective information in the object field spectrum through a multistage threshold image segmentation algorithm, adaptively adjusting the filtering bandwidth, optimizing a sampling strategy of a transfer function, and obtaining the effective information of the object field spectrum. Therefore, the calculation complexity and the memory occupation are remarkably reduced while the calculation precision is ensured. The method solves the problems of undersampling and computing resource waste in far-field diffraction calculation of a traditional angular spectrum method, is particularly suitable for diffraction calculation of a complex light field containing a high-frequency component, and has a wide application prospect in the fields of digital holography, light beam quality analysis and the like.

The invention relates to an intelligent dynamic response phase-locked loop filtering method and system, and belongs to the technical field of phase-locked loops, and the method comprises the steps: carrying out the fragmentation cooperative processing of a phase-locked loop output signal, so as to detect the noise characteristics of the output signal in real time, and the noise characteristics at least comprise the frequency domain noise distribution information of the output signal; dynamically matching the optimal filter bandwidth in the current noise environment according to the noise characteristics; and adjusting the actual bandwidth of the filter in the phase-locked loop according to the optimal filter bandwidth. According to the invention, the bandwidth can be dynamically adjusted according to the real-time signal noise environment, so that the optimal filtering effect can be obtained under different noise conditions.

This invention discloses a method for calculating and calibrating the cumulative radiance matrix within the effective bandwidth of a narrowband filter. The method first acquires the transmittance curve of the narrowband filter and determines the effective bandwidth integration interval. It then collects the response value matrix and dark background response matrix of a blackbody at multiple temperature points. Dark background correction and exposure normalization are performed on the response value matrix to obtain the blackbody bandwidth cumulative response matrix. Discrete integration is then performed on the blackbody spectral radiance and filter transmittance within the effective bandwidth integration interval to obtain the bandwidth cumulative radiance matrix corresponding to each temperature point. A polynomial mapping relationship between the bandwidth cumulative response matrix and the bandwidth cumulative radiance matrix is ​​established based on multi-temperature point samples. The global calibration coefficient set is obtained through least squares solution. After calibration, the original response value matrix and dark background response matrix of the object under test are acquired and subjected to consistent correction and normalization. These are then substituted into the mapping relationship to calculate and output the cumulative radiance matrix including the object under test. This method enables quantitative calculation of the cumulative radiance matrix within the effective bandwidth at the pixel level, avoiding errors caused by center wavelength approximation or single-point correction. It has the advantages of strong applicability, high computational efficiency, and simple engineering implementation.

The application provides a frequency shift control method, device and system of a repeater master-slave system, and belongs to the field of communication technology. The method applied to a master device comprises the following steps: performing bandwidth segmentation and interference signal energy scanning on a signal bandwidth corresponding to a current configuration frequency point according to a first bandwidth segmentation number to obtain a first scanning result; the scanning point for interference signal energy scanning corresponds to the bandwidth after signal bandwidth segmentation; determining a target frequency shift frequency point and a corresponding target bandwidth according to the first scanning result; configuring a master filter bandwidth and a master local oscillator frequency according to the frequency shift frequency point and the corresponding target bandwidth, and sending the frequency shift frequency point and the corresponding target bandwidth to a slave device of the repeater master-slave system; performing frequency shift processing on a received working signal according to the master filter bandwidth and the master local oscillator frequency, and sending a frequency-shifted signal after frequency shift processing to the slave device. The signal interference is reduced through the bandwidth segmentation and frequency shift mode, and the transmission effect is ensured.

A filter and a forming method thereof and an electronic device, the forming method comprising: after providing a piezoelectric laminated structure, a first thinning treatment is performed on a passivation layer in a target resonant region, so that the thickness of the passivation layer in the target resonant region is less than that in other resonant regions, and the vibration frequency of the passivation layer in the target resonant region is faster than that in other resonant regions, the frequency of the resonator in the target resonant region is right-shifted, which is beneficial to making the target resonant region used to form the resonator with the highest vibration frequency, and the performance of the filter bandwidth corresponding to the filter bandwidth is increased, because the first thinning treatment further reduces the surface roughness of the passivation layer in the target resonant region, which means that the thickness uniformity of the passivation layer in the target resonant region is improved, so that the right side frequency of the filter bandwidth is modulated, and the uniformity of the right side frequency of the filter bandwidth is improved, and more frequency points will fall within the range required by the specification during measurement, which is beneficial to improve the yield of the filter.

The invention provides an audio amplification system and a method thereof. The audio amplification system comprises a filter circuit, a signal generation circuit, a waveform conversion circuit, a driving circuit and a control circuit. The filter circuit is used for generating a filter signal according to an audio input signal, an audio output signal and a filter bandwidth. The signal generating circuit is used for generating an oscillation signal with an oscillation frequency. The waveform conversion circuit is used for generating a pulse modulation signal according to the filtering signal and the oscillation signal. The driving circuit is used for generating an audio output signal according to the pulse modulation signal. The control circuit is used for dynamically adjusting the filtering bandwidth and the oscillation frequency according to the digital control code. Wherein the digital control code and the audio input signal are both related to the audio input amplitude.

The present application belongs to the technical field of signal acquisition and processing, and discloses a low-noise bioelectric potential signal acquisition system and processing method. The original bioelectric signal of a human body is acquired through an electrode array, and is processed by a multi-stage adaptive filter amplification circuit and then subjected to analog-digital conversion. The digital signal is subjected to adaptive wavelet transform denoising and empirical mode decomposition to obtain a multi-level intrinsic mode function set, from which an intrinsic mode function of a characteristic frequency band is extracted and a signal is reconstructed. A double denoising mechanism combining adaptive wavelet transform and empirical mode decomposition is introduced. A signal quality real-time evaluation system is established, and system parameters, including a variable gain amplifier gain and a dynamic band-pass filter bandwidth, are dynamically adjusted through closed-loop feedback. The adaptive optimization of the whole bioelectric potential signal acquisition process is realized, various types of interference are effectively suppressed, signal characteristics are retained, and the signal-to-noise ratio is significantly improved.

The invention discloses a bandwidth-tunable time-varying optical filtering device and method based on a stimulated Brillouin scattering effect. A double-parallel Mach-Zehnder modulator is driven by a sweep-frequency electric signal to modulate an optical carrier, so that sweep-frequency pump light is generated; sweep frequency pump light is input into a nonlinear medium to excite frequency time-varying stimulated Brillouin gain, so that frequency time-varying optical filtering of a probe light signal can be realized; by changing the chirp rate, the bandwidth and the matching relation between the duration and the nonlinear medium of the sweep frequency pump light, the center frequency change rate, the change range and the filtering bandwidth of the time-varying optical filtering response can be changed; the unevenness of the time-varying optical filtering response can be compensated through amplitude pre-distortion of the sweep frequency pump light. The bandwidth-tunable time-varying optical filtering device and the bandwidth-tunable time-varying optical filtering method provided by the invention can process non-stationary optical signals, and have good application prospects in application scenes requiring time-varying narrow-band optical filtering, such as laser radar, optical fiber sensing, microwave photon filtering and the like.

The application relates to the technical field of data processing, and discloses a signal intra-pulse modulation pattern identification method and system, which comprises the following steps: receiving a radar pulse signal; performing short-time Fourier transform on the radar pulse signal; in a time-frequency matrix, calculating the energy distribution gradient of each time point along the frequency axis; identifying a gradient mutation point according to the energy distribution gradient of each time point; determining the filter bandwidth boundary based on the gradient mutation point by adopting a negative feedback adjustment mechanism of bandwidth and signal-to-noise ratio; performing bandwidth filtering on the radar pulse signal based on the filter bandwidth boundary; calculating the instantaneous frequency, the first-order differential frequency and the second-order differential frequency of the filtered signal through Hilbert transform, and forming a feature vector; predicting the clustering number range through a long short-term memory neural network according to the feature vector; performing clustering analysis within the clustering number range through a K-Means clustering algorithm according to the feature vector; and outputting a modulation pattern label according to the clustering analysis result.