28 results about "Zero frequency" patented technology

The invention discloses a frequency-modulated continuous wave laser radar signal generation method, a frequency-modulated continuous wave laser radar signal detection method and a frequency-modulated continuous wave laser radar signal detection system. The system comprises a transmitting end and a receiving end, wherein the transmitting end determines a frequency guard interval between a frequency-modulated continuous wave signal and zero frequency according to a modulation bandwidth of a radar signal and a line width of a transmitting laser; generating a frequency modulation continuous wave signal according to the frequency protection interval, modulating the frequency modulation continuous wave signal, generating radar detection signal light which is to be sent and contains residual carrier waves, performing power amplification on the radar detection signal light, and transmitting the radar detection signal light by using an optical lens; the receiving end receives the reflected signal light reflected by the target; filtering, beat frequency and coherent detection are carried out on the reflected signal light and the radar detection signal light to obtain an electric signal, and the electric signal is converted into a digital signal; performing electric domain filtering on the digital signal, and extracting a residual carrier and a beat frequency signal; performing phase noise compensation on the beat frequency signal based on the residual carrier to obtain a signal after phase recovery; and estimating the distance and the relative speed of the target based on the residual carrier and the phase-recovered signal.

The invention belongs to the technical field of microwave photons, and provides a double-ring photoelectric oscillator and a stabilizing method thereof. The oscillator is provided with a long ring and a short ring and comprises a stabilizing device; the stabilizing device comprises a first piezoelectric ceramic optical fiber stretcher, a motor space light delay line and a second piezoelectric ceramic optical fiber stretcher; generating two optical probe signals; the first optical probe signal is converted into a first electric probe signal through the long ring; a second optical probe signal is converted into a second electric probe signal through the short ring; an electric probe signal is output after being subjected to detection, coupling and power division; the two frequency mixers respectively carry out homodyne frequency mixing on the electric probe signal and the phase-shifted and non-phase-shifted radio frequency signals to generate a zero-frequency error signal; the two phase-locked loops generate compensation control signals according to the error signals; the control signal adjusts an optical fiber delay line; the stability of the two loops is ensured, the problem of combined signal frequency drift caused by neglecting short-loop delay change is solved, the coherence requirement on optical signals is avoided by electric domain combination, and smooth tuning of the output radio frequency signal frequency is realized.

The application provides a modulation method and system of an orthogonal frequency division multiplexing signal, and belongs to the technical field of wireless communication. The method comprises the following steps: mapping a frequency domain data signal and a pilot signal to be transmitted into a frequency domain resource grid matrix; performing a frequency domain shift operation on each row vector of the frequency domain resource grid matrix, shifting a zero frequency component to the center of the vector, and obtaining a shifted matrix; and performing an inverse fast Fourier transform on each row vector of the shifted matrix, and obtaining a time domain orthogonal frequency division multiplexing symbol matrix as a modulation result. The application constructs the entire frequency domain resource into a two-dimensional matrix, and all subsequent signal processing operations are based on the row vectors of the two-dimensional matrix as a basic unit, and are completed through a series of explicit matrix and vector operation steps. Thus, the IFFT call for the entire frame, which is a black box, is decomposed into individual steps for a single symbol, which are visible and controllable, and the problem of opaque process is solved.

The present application relates to a kind of based on comb spectrum implementation wideband signal transmitting device amplitude phase flatness analytical method, comprising the following steps acquisition measured link's time domain complex IQ sampling data;Perform fast Fourier transform;Zero frequency component is moved to spectrum center;Calculate the index of each target frequency in spectrum array;The amplitude and phase at each index are calculated;Calculate preliminary amplitude error and phase error;Get amplitude flatness distortion;Interlaced phase correction is carried out;Phase unwrapping is carried out;Get phase flatness distortion;Filter out abnormal value;Output amplitude flatness distortion and phase flatness distortion result.The wideband signal transmitting device amplitude phase flatness analytical method based on comb spectrum implementation of the present application, system, device, processor and its computer readable storage medium, around the flatness calibration demand of wideband wireless signal transmitting device, obtains the flatness information of transmitting device from comb spectrum, realizes the asynchronous acquisition and efficient analysis without synchronization.

A method for zero-point correction of an S-parameter model includes: calculating the S-parameters at zero frequency based on the constructed S-parameter model; calculating the error matrix between the S-parameter model and the original S-parameters at zero frequency; calculating the residues corresponding to the preset real poles based on preset real poles and the error matrix; and adding a term to the S-parameter model using the preset real poles and their corresponding residues to obtain the zero-point corrected S-parameter model. This method further corrects the S-parameters after vector fitting and passivity correction, ensuring that the values ​​of the S-parameters at zero frequency remain consistent with the original S-parameters while minimizing disruption of the original model's passivity and maintaining accuracy. This corrects the error of the original model's S-parameters at zero frequency, eliminating errors in subsequent simulations caused by the inaccuracy of the S-parameters at zero frequency.

The invention belongs to the technical field of microwave photons, and provides a double-ring photoelectric oscillator with a stabilizing device and a stabilizing method thereof, the double-ring photoelectric oscillator is provided with a long ring, a short ring and a stabilizing device; the stabilizing device comprises a first piezoelectric ceramic optical fiber stretcher and a motor space light delay line; the radio frequency signal source generates a first optical probe signal and a second optical probe signal through modulation; the first optical probe signal is converted into a first electric probe signal after passing through the long ring; a second optical probe signal is converted into a second electric probe signal after passing through the short ring; the first frequency mixer and the second frequency mixer are used for performing homodyne frequency mixing on the electric probe signal and the radio frequency signal to generate a zero frequency error signal; and the two phase-locked loops generate compensation control signals according to the zero-frequency error signals. According to the invention, by outputting the control signal and adjusting the optical fiber delay line, the stability of two loops is ensured, the problem of combined signal frequency drift caused by neglecting short-loop delay change is solved, and the coherence requirement on two paths of optical signals is avoided by electric field combination.

The application provides a lumped parameter topology for realizing generalized Chebyshev band-pass frequency response by using lumped parameter elements, which specifically includes two types of structures, GCL and GCB. The generalized Chebyshev band-pass frequency response includes two types of double-side generalized Chebyshev band-pass frequency response and single-side generalized Chebyshev band-pass frequency response. The response is characterized in that the response amplitude in the passband is equal ripple fluctuation, has three transmission poles, and two transmission zeros can be flexibly placed at limited frequencies, which are any positive frequencies except zero frequency and infinite frequency. The GCL structure is used for realizing double-side generalized Chebyshev band-pass frequency response, and the GCB structure is used for realizing single-side generalized Chebyshev band-pass frequency response. The application effectively overcomes the limitations of the prior art, and realizes more complex frequency response by flexibly setting transmission zeros.

The application relates to the radar technical field and discloses a continuous wave radar detection method, which comprises the following steps: generating an initial radio frequency carrier signal; applying a preset frequency offset to the initial radio frequency carrier signal to generate a transmission signal; radiating the transmission signal to a detection space through a transmission antenna; receiving a return signal formed by reflection of the transmission signal by a target in the detection space through a receiving antenna; and mixing the return signal with the initial radio frequency carrier signal to obtain a first intermediate frequency signal; wherein the preset frequency offset is configured so that, for a stationary target, the first intermediate frequency signal is a signal with a frequency equal to a preset non-zero frequency value; and the first intermediate frequency signal is processed to obtain information related to the state of the target. The spectrum of the effective signal is actively shifted to a frequency point away from a high-noise low-frequency area, and the detection sensitivity for stationary or micro-motion targets is enhanced. The application further discloses a continuous wave radar detection device, a radar and a storage medium.

The application belongs to the technical field of surveying, and provides an improved method for surveying underground water in high-resistance surrounding rock area by using transient electromagnetic method, which comprises the following steps: obtaining high-resistance surrounding rock area, collecting transient electromagnetic data in the high-resistance surrounding rock area, checking whether negative response exists in late channel, introducing Cole-Cole model to carry out forward modeling when the negative response exists, extracting zero-frequency resistivity, charging rate, time constant and frequency correlation coefficient, simultaneously solving zero-frequency resistivity and three induced polarization parameters by using quasi-two-dimensional regularization Newton inversion, and delineating underground water-bearing stratum by joint interpretation of zero-frequency resistivity and three induced polarization parameters. The application is aimed at the negative response of late channel caused by induced polarization effect of underground water in high-resistance surrounding rock area, and can extract zero-frequency resistivity and other three induced polarization parameters by using the negative response, and carry out underground water surveying by using quasi-two-dimensional regularization Newton inversion interpretation.

The application discloses an optical frequency comb locking system for eliminating carrier envelope phase shift frequency, and the disclosed system comprises an optical frequency comb, a repetition frequency detector, a carrier envelope phase shift detector, an attenuator, an operational amplifier, a filter, a power divider, a double balanced mixer, a bias voltage and a phase-locked loop; the system extracts the sum and difference frequencies of the repetition frequency and the carrier envelope phase shift frequency of the optical frequency comb, and locks them to each other, so as to realize the carrier envelope phase shift frequency locking to zero frequency, and reduce the difficulty of the optical frequency comb locking. The application solves the problem of high locking difficulty of the traditional optical frequency comb, simplifies the carrier envelope phase shift frequency control, has the feasibility of productization and high integration, has universality, and can be widely applied to different types of optical frequency comb systems.

The invention discloses a zero-frequency signal amplitude reduction method and system based on a multi-cut full-parallel FIR filter, and belongs to the technical field of chip digital design, and the method comprises the steps: executing the CSD multiplication of a filter coefficient and input data, and obtaining a plurality of partial products; carrying out cutting processing on the plurality of partial products respectively; calculating a compensation value of a truncation error based on the symbol attributes of the plurality of partial products and the state of the least significant bit after truncation; and accumulating the plurality of partial products after cutting processing and the compensation value to obtain filtering output. The invention solves the problems that the zero-frequency signal amplitude of the filter is obviously increased and the resource efficiency and the signal precision are difficult to consider at the same time due to the fact that the truncation digits are increased for reducing hardware resources in the prior art.

The invention discloses an IQ imbalance calibration method and system. The method comprises pre-calibration and fine calibration. During pre-calibration, firstly, M frequency points are selected in a sectional mode, narrow-band calibration is carried out, correlation factors of amplitude imbalance errors and phase imbalance errors of the multiple frequency points are obtained, interpolation fitting is carried out on zero frequency points, and frequency response characteristics in the whole bandwidth are obtained. On the basis, a solution equation is constructed to calculate a filter coefficient, and a filter is designed to compensate the IQ imbalance error. During fine calibration, based on the least square method, the compensation coefficient of the filter is calculated in a real-time and self-adaptive manner, whether iteration is updated or not is judged, iterative filtering is carried out to enhance the stability of the system, and the problem of calibration performance deterioration caused by environmental factors such as temperature change is effectively solved. Compared with traditional narrowband calibration, the calibration system combining pre-calibration and fine calibration has a calibration effect on receiver large-bandwidth IQ imbalance, the adaptive capacity of the calibration system to environment temperature changes is enhanced, and the calibration precision and robustness are improved.

The invention provides an orthogonal frequency division multiplexing signal modulation method and system, and belongs to the technical field of wireless communication, and the method comprises the steps: mapping a to-be-transmitted frequency domain data signal and a to-be-transmitted pilot signal to a frequency domain resource grid matrix; performing frequency domain moving operation on each row vector of the frequency domain resource grid matrix, and moving a zero frequency component to a vector center to obtain a moved matrix; and performing inverse fast Fourier transform on each row vector of the moved matrix to obtain a time domain orthogonal frequency division multiplexing symbol matrix as a modulation result. According to the invention, the whole frequency domain resource is constructed into a two-dimensional matrix, and all subsequent signal processing operations take the row vector of the two-dimensional matrix as a basic unit and are completed through a series of clear matrix and vector operation steps. In this way, IFFT calling of a black box for the whole frame is deconstructed into visible and monitorable steps for single symbols, and the problem that the process is not transparent is solved.

This invention discloses an adaptive cancellation circuit for a frequency-modulated continuous wave radar, comprising the following components: a power divider, which splits the radar signal into two output signals, namely a first transmitted signal and a second signal LO; and a mixer, which receives the two output signals from the power divider, one of which serves as the local oscillator and the other as the receiver; the self-coupling signal delay at the RF input port of the mixer is the same as the delay of the second signal LO. This invention increases the LO trace delay, making the LO trace path delay equal to the antenna self-coupling path delay, thereby bringing the self-coupling intermediate frequency (IF) signal output close to zero frequency. This allows the self-coupling IF signal to be easily filtered out, significantly reducing the signal-to-noise ratio degradation caused by the impulse response.

1. Name of the product in this design: Uniaxial zero-frequency sensor. 2. Application of this design: A sensor for high-precision measurement under static or extremely low frequency (near DC) signals. 3. The key design feature of this product is its shape. 4. The image or photograph that best illustrates the design's key points: 3D view 1.

The present application belongs to the field of integrated circuit manufacturing online measurement, and discloses a snapshot overlay error measurement method and system, which comprises the following steps: measuring a measured object, obtaining two measurement spectra with positive and negative preset deviations respectively, coherently demodulating the measurement spectra, and shifting the specific frequency channel to the zero frequency channel; processing the spectrum data after frequency shifting by using a linear operator to obtain the coefficients corresponding to the positive and negative preset deviations; constructing a characteristic quantity according to the linear combination of the real part and the imaginary part of the coefficients, then calculating the corresponding characteristic quantity according to the coefficients corresponding to the positive and negative preset deviations; and calculating the overlay error according to the characteristic quantity based on the linear relationship between the characteristic quantity and the overlay error. The present application can solve the overlay error with multi-wavelength coupling without using traditional Fourier analysis and truncation operation, has high precision and robustness to noise, and can be used for data processing of snapshot overlay error measurement in multiple scenes.

The invention discloses a frequency-stabilized phase-locked intermediate infrared single-cavity double-comb measurement system and method, and solves the problems of complex system structure and huge size caused by the need of ultra-stable external optical / microwave reference, pumping broadband servo locking, high-frequency precise electric control loop and the like in the conventional double-comb measurement system. According to the invention, a homologous pumping single-cavity double-comb architecture is adopted, and an innovative mechanism of eliminating pumping frequency and zero frequency offset by combining optical and electrical frequency mixing is adopted, so that complex means such as reference frequency locking, repetition frequency and carrier envelope offset frequency detection required by a traditional scheme are not needed, and the method has the advantages of being easy to construct and simple and convenient to operate.

The application provides a kind of lumped parameter topology for realizing four-order generalized Chebyshev band-pass frequency response, which is specifically represented as two kinds of structures of GCL and GCB.The generalized Chebyshev band-pass frequency response includes two kinds of double-sided generalized Chebyshev band-pass frequency response and single-sided generalized Chebyshev band-pass frequency response.The response is characterized in that the response amplitude in the passband is equal ripple fluctuation, has four transmission poles, and three transmission zeros can be flexibly placed at limited frequencies, which are any positive frequencies except zero frequency and infinite frequency.The GCL structure is used to realize the double-sided generalized Chebyshev band-pass frequency response, and the GCB structure is used to realize the single-sided generalized Chebyshev band-pass frequency response.The application effectively overcomes the limitations of the prior art, and realizes more complex frequency response by flexibly setting transmission zeros.

The application relates to the technical field of receiving radio frequency front ends, and discloses a super-high-blocking-sensitivity super-short-wave multi-channel parallel receiving radio frequency front end. After sampling processing of sampling data, a target analog-to-digital converter turns on corresponding channel selection input switches and channel selection output switches according to the type of the sampled radio frequency signals, so as to select a suitable radio frequency signal processing branch to be accessed, to perform low-noise amplification and large-signal attenuation processing on the radio frequency signals, and to ensure that the radio frequency signals entering the target analog-to-digital converter are within the target analog-to-digital converter's spurious-free dynamic range, thus getting rid of the narrow-band signal processing capability in the traditional superheterodyne signal architecture. The advantage lies in that, through the frequency conversion effect of a mixing circuit, interference is mixed to zero frequency or is pulled away from useful signals. For zero-frequency signals, the interference can be suppressed through a blocking capacitor, and the frequency multiplication of the interference signals can be suppressed through a low-pass filter, so that the function of only suppressing interference signals without deteriorating useful signals is realized, and the dynamic range of the receiving front end is improved.

The invention relates to a method for realizing amplitude-phase flatness analysis of broadband signal transmitting equipment based on a comb spectrum. The method comprises the following steps: acquiring time domain complex IQ sampling data of a measured link; performing fast Fourier transform; moving the zero frequency component to a frequency spectrum center; calculating an index of each target frequency in the frequency spectrum array; calculating the amplitude and phase of each index; calculating a preliminary amplitude error and a phase error; amplitude flatness distortion is obtained; performing staggered phase correction; phase unwrapping is carried out; obtaining phase flatness distortion; abnormal values are filtered out; and outputting amplitude flatness distortion and phase flatness distortion results. According to the method, the system, the device, the processor and the computer readable storage medium for realizing the amplitude-phase flatness analysis of the broadband signal transmitting equipment based on the comb spectrum, the flatness information of the transmitting equipment is calculated from the comb spectrum according to the flatness calibration requirement of the broadband wireless signal transmitting equipment; and asynchronous acquisition and efficient analysis without synchronization are realized.

This application provides a channel estimation-based tracking method, electronic device, and storage medium. The method includes: cleaning the channel estimation information corresponding to each antenna element to obtain the target channel estimation result for each antenna element; selecting the smallest non-zero frequency domain channel estimation value from the target channel estimation results of the target antenna element as a first adjustment coefficient; amplifying the first adjustment coefficient according to a preset amplification factor to obtain a second adjustment coefficient; adjusting the target channel estimation result of the target antenna element using the first adjustment coefficient to obtain a first channel estimation result; adjusting the target channel estimation result of the antenna element under a specified receiver using the second adjustment coefficient to obtain a second channel estimation result; determining a specified channel estimation result using the first channel estimation result and the second channel estimation result; and tracking a passive target based on the specified channel estimation result of each antenna element. This application achieves accurate tracking of passive targets.

The invention discloses an LC filter with adjustable frequency, bandwidth and zero point. The LC filter comprises three adjustable circuit modules including a zero point configuration circuit, a coupling configuration circuit and a resonance configuration circuit. Wherein the two sets of resonance configuration circuits which are symmetrically arranged are connected through the coupling configuration circuit, and the two sets of zero point configuration circuits are respectively connected to the input end, the output end and the resonance circuit. The structure independently controls the center frequency point, the bandwidth and the zero frequency in an electric adjustment mode. Compared with a traditional multi-filter parallel connection or complex switch array scheme, multi-band and multi-bandwidth signal processing can be achieved only through a single reconfigurable unit, and therefore the number of components and the circuit scale are remarkably reduced. Therefore, the hardware size is greatly reduced, the equipment space is saved, and the material cost and the assembly complexity are effectively reduced due to simplification of a peripheral circuit. The system adaptability is enhanced by the height adjustability, and a high-performance, miniaturized and low-cost solution is provided for the field in which the frequency response needs to be quickly reconstructed.

The invention discloses an ISAR (Inverse Synthetic Aperture Radar) range envelope alignment method and system based on phase difference, and belongs to the technical field of radars. The method comprises the following steps: sampling echo signals after pulse compression one by one, estimating and compensating adjacent sampling average phase change; partitioning azimuth signals in a distance frequency domain, respectively adding rectangular windows by taking zero frequency as a boundary, and sampling in each azimuth to generate an upper sideband signal and a lower sideband signal; performing three-time conjugate multiplication on four adjacent sampled signals to obtain a differential signal; obtaining an adjacent offset through maximum likelihood estimation by using the differential signal; aligning the adjacent envelopes according to an estimation result; and after the aligned envelopes are accumulated, the steps are repeated for recursion with the next sample, and finally, envelope alignment of all the samples is completed. According to the method, the sub-pixel-level distance envelope alignment precision can be realized without up-sampling and interpolation operations, and the problem of echo generation caused by amplitude modulation in a traditional amplitude dependent algorithm is effectively avoided.

This invention provides a coarse synchronization segmentation design method for 5G self-organizing networks based on domestically produced chips, relating to the field of mobile communication technology. The method includes the following steps: S1, capturing air interface signals according to the sampling rate issued by OAM and the common NRSSB cycle; S2, calculating the frequency difference and performing zero-frequency shifting based on the center frequency of the receiving bandwidth; S3, segmenting and merging the zero-frequency shifted signal into windows, and performing downsampling processing on the signal; S4, performing AGC gain processing on the signal; S5, performing in-window decision on the signal; S6, after all in-window signals have completed in-window decision, performing inter-window decision; S7, setting a timeout threshold and dynamically adjusting the window length. The beneficial effects of this invention are: reduced computational complexity, efficient utilization of computational resources, improved computational efficiency, and high accuracy and reliability of signal detection.

The application discloses a high-temperature solid internal temperature measurement method based on nonlinear ultrasonic zero-frequency signals and belongs to the technical field of nondestructive measurement. The method comprises the following steps: firstly, ultrasonic waves are excited on one side of a solid structure under different uniform temperature field conditions, and ultrasonic signals are received on the other side; after the signals are processed, the amplitudes of the nonlinear ultrasonic zero-frequency signals under different uniform temperature fields are observed and recorded; then, the correlation between the amplitudes of the nonlinear ultrasonic zero-frequency signals and temperature is determined; after the correlation between the amplitudes of the nonlinear ultrasonic zero-frequency signals and temperature is determined, the temperature inside the solid structure is obtained in subsequent ultrasonic detection by combining the correlation between the amplitudes of the nonlinear ultrasonic zero-frequency signals and temperature. The application is not limited to the type of solid material, can be used for stable measurement under high-temperature or extremely high-temperature environments, has far higher sensitivity than linear ultrasonic parameters and has good real-time performance.

This invention discloses a high-precision time delay estimation method based on parallel factors. First, L monitoring nodes receive radiated signals, and the received signals undergo Fourier transform. Second, non-zero frequency band signals are extracted, and frequency domain data from each monitoring node are fused to construct a trilinear model. Then, the parallel factor method is used, and the trilinear alternating least squares method is employed for decomposition and iteration to obtain the frequency domain time delay estimation matrix. Finally, a normalization method is used to eliminate scale ambiguity, and the Vandermonde feature of the time delay matrix is ​​used for time delay estimation. Compared with traditional methods, this invention achieves higher accuracy in time delay estimation, effectively improving positioning accuracy; it eliminates the need for spectral peak search, resulting in relatively low computational complexity; and by fusing frequency domain data from multiple nodes, multiple time delay estimates can be obtained simultaneously without the need for node-specific processing, making it of significant application value.

The embodiment of the application provides a kind of sampling digital front-end signal processing method and system, comprising: obtaining the expected received digital radio frequency signal of each channel;According to the frequency of the channel of expected received digital radio frequency signal, generate digital local oscillator signal;Using digital local oscillator signal to the expected received digital radio frequency signal is quadrature mixed to be expected received digital radio frequency signal Channel down conversion to zero frequency, obtain the first in-phase / quadrature two-way baseband signal;After filtering and downsampling processing to the first in-phase / quadrature two-way baseband signal, obtain the second in-phase / quadrature two-way baseband signal;The second in-phase / quadrature two-way baseband signal is processed and whether the second in-phase / quadrature two-way baseband signal after processing is ILS-LOC signal or GLS-VDB signal is judged.Processed.

The application discloses a kind of dynamic phase compensation demodulation method and system for Φ-OTDR system, belong to distributed optical fiber sensing technical field.The method includes: first, interference signal is divided into four paths, respectively, zero frequency processing, one frequency mixing, one frequency quadrature mixing and two frequency mixing, through the energy extraction and difference operation of quadrature signal, eliminate carrier phase delay influence;Second, using the recurrence relation of Bessel function, combined with differential and difference operation, real-time calculation modulation depth and eliminate light intensity disturbance, finally restore the phase to be measured.The application overcomes the nonlinear distortion of traditional PGC demodulation algorithm from the root, significantly improves the system anti-interference robustness and phase demodulation accuracy, can realize the rapid, high-fidelity recovery of high-frequency dynamic vibration event along the whole optical fiber.The application can be widely applied to perimeter security, rail transit, long-distance pipeline early warning and ocean sensing and other fields.