187results about How to "Reduce phase error" patented technology

A clock and data recovery (CDR) circuit includes a sampler, a CDR loop and a phase interpolator. The sampler samples serial data in response to a recovery clock signal to generate a serial sampling pulse. The CDR loop transforms the serial sampling pulse into parallel data, generates a plurality of phase signals with a first speed based on the parallel data, and generates a phase control signal with a second speed higher than the first speed based on the plurality of phase signals. The phase interpolator generates the recovery clock signal by controlling a phase of a reference clock signal in response to the phase control signal. Therefore, the CDR circuit may recover data and a clock with a relatively high speed.

The invention relate to systems and methods for sequencing polynucleotides, as well as detecting reactions and binding events involving other biological molecules. The systems and methods may employ chamber-free devices and nanosensors to detect or characterize such reactions in high-throughput. Because the system in many embodiments is reusable, the system can be subject to more sophisticated and improved engineering, as compared to single use devices.

The invention provides a clock adjustment circuit and an adjustment method for a clock circuit. The clock adjustment circuit comprises a clock buffer amplifier, a phase discriminator and a duty cycle adjustment circuit, wherein the clock buffer amplifier is used for receiving an external differential clock signal, shaping the differential clock signal into a single-end square wave clock signal and outputting the single-end square wave clock signal; the phase discriminator is used for receiving the single-end square wave clock signal from the clock buffer amplifier and a feedback signal from the duty cycle adjustment circuit, comparing the phase of the single-end square wave clock signal with the phase of the feedback signal to acquire a phase difference, and outputting the phase difference; and the duty cycle adjustment circuit is used for adjusting the duty cycle of the feedback signal by using the phase difference to acquire an adjusted feedback signal. The differential signal is shaped into the single-end square wave clock signal, the single-end square wave clock signal is compared with the feedback signal to acquire the phase difference, and the duty cycle is adjusted according to the phase difference, so that the complexity of duty cycle adjustment and hardware implementation can be effectively reduced, phase errors and the ripple waves of control voltage can be reduced, and adjustment accuracy is improved.

In one embodiment, a phase-locked loop system in a receiver samples received incoming data using a first clock and a second clock that have the same frequency but are out of phase with each other. A first control signal generated by a phase detector is used to control a charge pump, whose output may be filtered to drive a VCO circuit generating the first and second clocks. A frequency detector generates a second control signal based at least on phase relationships between the incoming data and the first and second clocks. A qualifier circuit determines if the first control signal is valid or invalid based at least on the second control signal. If the first control signal is invalid, the qualifier circuit prevents the first control signal from being used to adjust the frequency of the first and second clocks.

The invention discloses a clock circuit capable of realizing a stable duty ratio and phase calibration, which is used for adjusting the duty ratio and the phase of a clock signal. The clock circuit comprises a clock distribution network used for carrying out buffer output on the clock signal, a duty ratio correction module and a phase calibration module, wherein the duty ratio correction module is used for converting an input differential signal into a square signal with a fixed duty ratio and then outputting the square signal to the phase adjustment module; and the phase adjustment module is used for adjusting the phase of the input square signal by utilizing an in-phase clock signal and an antiphase clock signal which are fed back by the clock distribution network and generating and inputting a clock signal to the clock distribution network. By adopting the clock circuit, the purposes of stable duty ratio and phase calibration of the output clock signal are achieved.

The invention belongs to an imaging method for nonlinear frequency modulation label change in the synthetic aperture radar imaging technology, which comprises the steps of two-dimensional frequency domain unfolding, filtering processing, nonlinear frequency modulation label change, distance compression, distance migration correction, rest phase compensation and position compression. In the method of the invention, the characteristics of orthogonality and minimum square error of the Legendre polynomials are utilized for carrying out three-order unfolding on the two-dimensional frequency domain signals of the obtained echo signals according to the Legendre orthogonality polynomials, and then, the focusing imaging on targets is realized through carrying out filtering processing and the like on three-order phase items in echo signal two-dimensional frequency domain expression. When the method of the invention is adopted, the maximum phase error under the same condition is less than 0.2 percent of the maximum phase error in the prior art, so the assurance is provided for the high-precision imaging under the large-inclination view angle condition. Therefore, the method of the invention has the characteristics that the phase error in the imaging process can be effectively reduced, the imaging processing of the large-inclination view angle is realized, in addition, the imaging effect is good, the imaging processing efficiency and the precision are high, and the like.

The present invention provides an improved frequency doubling circuit, with adjustable phase offset. Briefly, rather than using the traditional equations cos (2ωt)=cos 2(ωt)−sin 2(ωt) and sin(2ωt)=2 sin(ωt)cos(ωt), the quadrature output signals are generated utilizing mixers, each having two input signals, separated in phase by the same offset. This minimizes the effects of the non-linearities introduced by the mixer, which therefore reduces amplitude mismatch between the quadrature signals. Also, the phase offset of the quadrature output signals can be tuned and calibrated using a phase shifting circuit. This phase shifting circuit realizes a tuning range of approximately 5° in programmable steps. This combination of circuits can be used to minimize the amplitude mismatch and phase errors, thereby reducing the amplitude of and interference caused by transmission of the image frequency to the receivers input.

The invention discloses a Bayesian iterative reweighted sparse autofocus array synthetic aperture radar (SAR) imaging method. The Bayesian iterative reweighted sparse autofocus array SAR imaging method aims at the influence of phase errors existing in array SAR echo signals on imaging results. Based on a traditional sparse autofocus Bayesian recovery via iterative minimum (SAFBRIM) algorithm, a linear measurement matrix of scattering coefficients in the array SAR original echo signals and an observation scene target space is established, norm items in a cost function in the algorithm are subjected to iterative adaptive reweighted processing, pulse compression and equidistant surface division are carried out on a distance direction, and then each equidistant two-dimensional surface is estimated. According to the Bayesian iterative reweighted sparse autofocus array synthetic aperture radar (SAR) imaging method, different weighting coefficients are given to each norm item, and then imagesare reconstructed, so that higher-quality array SAR imaging results can be obtained. The Bayesian iterative reweighted sparse autofocus array synthetic aperture radar (SAR) imaging method has the advantages of high reconstruction precision and effective reduction of phase errors, and can be applied to the fields such as array synthetic aperture radar imaging.

The invention discloses a method for optimizing SAR (Specific Absorption Rate) extended scene imaging on a double-base forward-looking high-mobility platform. The method comprises the following main steps: obtaining an SAR time domain echo signal of a point target at first so as to obtain an echo signal and a range history after the linear moving amount is corrected, and then, carrying out azimuth FFT (Fast Fourier Transform) of the echo signal after the linear moving amount is corrected so as to obtain a two-dimensional frequency spectrum of the time domain echo signal; and carrying out high-order approximation of the range history after the linear moving amount is corrected, carrying out Taylor series development in the range direction after obtaining the phase term of the high-precision two-dimensional frequency spectrum after the linear moving amount is corrected, eliminating the phase space-variant property of the phase term of the high-precision two-dimensional frequency spectrum by adopting high-order polynomial fitting, carrying out range domain IFFT (Inverse Fast Fourier Transform) after obtaining a phase compensation signal having good focus in the range domain through a matching filter designed through the two-dimensional frequency domain, and then, obtaining focused SAR imaging through the matching filter designed in a range-Doppler domain.

The invention, which belongs to the signal processing technology field, discloses an optimization method based on traditional phase difference measurement and a circuit. According to the method, two sinusoidal signals with different frequencies or a same frequencies pass through a signal collection circuit, an amplification circuit, and a comparison circuit as well as two paths of rectangular wave signals pass through an OR gate circuit so as to obtain a needed pulse signal; AD sampling is carried out so as to obtain a pulse width and a time difference of signal zero crossing, so that a phase difference is calculated. According to the invention, because a special circuit design is employed, phase drift generated by hardwares of a traditional zero cross detection circuit itself can be substantially changed, so that correlated subsequent processing of the phase difference on software becomes easier; therefore, the strong practicality is realized.

The invention relates to a power transformer winding fault online monitoring device and a diagnosis method, and belongs to the technical field of power transformer fault diagnosis. The power transformer winding fault online monitoring device is characterized in that the output end of a voltage sensor and the output end of a current sensor are connected to the input end of a synchronous signal sampling circuit, the output end of the synchronous signal sampling circuit and the output end of an ultrahigh frequency sensor are connected to the input end of a signal conditioning circuit, the output end of the signal conditioning circuit is connected to the input end of a DSP (Digital Signal Processor) through an A/D conversion circuit, the output end of the DSP is connected with a PC (Personal Computer) through a CPLD (Complex Programmable Logic Device), and the PC is connected with an alarm. The diagnosis method comprises the steps of acquiring ultrasonic signals at the wall of a transformer oil tank, and finally acquiring coordinates of partial discharge through signal conditioning and A/D conversion and through DSP denoising; acquiring voltage signals and current signals, processing the signals, building an online short-circuit reactance model, acquiring a short-circuit reactance value of each phase winding, comparing the acquired short-circuit reactance value with a corresponding historical fault-free short-circuit reactance value so as to acquire the short-circuit reactance change rate, judging a range, in which the change rate is located, of an upper limit threshold and a lower limit threshold, and judging the winding operating state.

The invention discloses a synchronous orbit SAR (Synthetic Aperture Radar) imaging method based on high-order polynomial range equation. The implementation process thereof is as follows: 1. establishing a synchronous orbit SAR high-order polynomial range equation; 2. solving a Cardan equation and deducing the precise analytical expression of a synchronous orbit SAR echo signal two-dimensional frequency spectrum; 3. structuring a two-dimensional frequency domain compensation function and finishing a scene centre point matching processing in the two-dimensional frequency domain; 4. performing arange IFFT (Inverse Fast Fourier Transform) processing on a result after finishing the centre point matching and transforming the result to a range-Doppler domain from the two-dimensional frequency domain; 5. structuring an error phase spatially variant with range and compensating for a range spatially variant phase in the range-Doppler domain; and 6. performing an azimuth IFFT processing to obtain a focused synchronous orbit SAR image. All the operations in the invention are finished by fast Fourier transform and phase dot product, and the method is high in efficiency and suitable for engineering implementation; and moreover, the two-dimensional frequency spectrum is a precise analytic solution capable of realizing full-aperture and high-resolution imaging.

The invention discloses a high-downdip electrically controlled base station antenna. The antenna comprises a reflection board, an array, a phase shift mechanism and an adjusting mechanism, wherein the array is arranged on one side of the reflection board and is provided with multiple dual-polarized vibrators; the phase shift mechanism and the adjusting mechanism are arranged on the other side of the reflection board; the phase shift mechanism is provided with a first shunt-feed strip-shaped wire and a first medium board; the first shunt-feed strip-shaped wire is connected with the dual-polarized vibrators, and is provided with a tap and multiple conduction bands reversely extending from the edge of the tap; the first medium board is simultaneously overlapped on at least part of the reversely extended conduction bands; and the adjusting mechanism is connected with the first medium board so as to drive the first medium board to move in the extension direction of the conduction bands. The antenna has the advantages that: the first shunt-feed strip-shaped wire is provided with multiple reversely extended conduction bands and the first medium board is simultaneously overlapped on the reversely extended conduction bands, so that the first medium board is matched with the reversely extended conduction bands to form multiple parallel-connection phase shift units, thus the feeding network layout is simplified, the feeding loss is reduced, the benefit is increased and the bandwidth is broadened.

The invention relates to a Legendre-orthogonal-decomposition-baesd curve motion trajectory SAR wave-number domain imaging method. The method comprises: constructing a slant range history expression ina curved motion trajectory mode by using a three-dimensional speed and a three-dimensional acceleration; carrying out polynomial expansion on the constructed slant range history expression and carrying out keeping to the fourth order; transforming an SAR echo signal corresponding to the slant range into a two-dimensional frequency domain to obtain a two-dimensional frequency spectrum; with a Legendre orthogonal polynomial, spreading the two-dimensional frequency spectrum for a distance range frequency and carrying out keeping to a third order; carrying out phase compensation based on a two-dimensional frequency spectrum developed based on Legendre and completing distance migration correction and distance range focusing; and carrying out azimuth compression in a distance-Doppler domain andcarrying out transformation in a two-dimensional time domain to obtain a focusing image. Therefore, a target imaging blurring problem at the scene edge is solved.

The invention discloses a combined X-band five-bit phase shifter based on active and inactive structures, and mainly solves the problems of large gain error and low phase shift precision in the priorart. The phase shifter comprises filters (1), an active balun (3) and switches (4); multiple filters and switches are respectively provided and are alternately connected; the last switch is connectedwith an input end of the active balun; an output end of the active balun is connected with an orthogonal signal generator (2) and is used for generating positive and negative in-phase signals and positive and negative orthogonal signals; and an output end of the orthogonal signal generator is connected with a one-in-four circuit (5), and is used for selecting one path of signals from four paths ofsignals, namely the positive and negative in-phase signals and the positive and negative orthogonal signals to output, thereby implementing transformation of the signals among four quadrants. The phase shifter has the advantages of small gain error and high phase shift precision, and can be used in a radio-frequency integrated circuit in which a high-precision phase shifter is needed by a radio-frequency microwave phased array receiver.

The invention belongs to the technical field of electronic information and discloses a determination method of an antenna array phase response parameter. The determination method comprises initialization processing. A sample autocorrelation matrix of an antenna array receiving signal vector is determined. A signal subspace matrix and a noise subspace matrix of the sample autocorrelation matrix are determined. A direction matrix is determined. A signal guiding vector is determined. Finally, an antenna array phase response parameter is determined. According to the method, the signal subspace matrix of the antenna array receiving signal vector is used for establishing a non-phase vector and the direction matrix, and by determining signal direction, the signal guiding vector and the like, the antenna array phase response parameter is determined. The method is used for determination, and the correlation coefficient of the result and a practical phase response parameter vector is larger than 0.99. Accordingly, under the situation that signal direction is unknown, the antenna array phase response parameter can be determined effectively, the method has the advantages that errors between the determined phase response parameter and the practical phase response parameter are small, and similarity is high.

The invention discloses a nonlinear phase error correcting method based on a digital projection three-dimensional measuring system. The system comprises the steps of setting a stripe space period as M, setting an actual stripe phase shifting step number as N, setting a phase shifting step number of a phase error stripe pattern as N', setting t as a coefficient, generating an NXN' step phase shifting stripe pattern by a computer according to the stripe pixel period M= tXNXN', projecting the stripe pattern onto a white board by the three-dimensional measuring system, and collecting an actual phase shifting stripe pattern; extracting the collected phase shifting stripe pattern, obtaining N' groups of N step phase shifting stripe patterns, calculating actual phases and corresponding NXN' stepideal phases, obtaining phase errors, and obtaining N' phase error patterns; and calculating the amplitude of the phase shifting stripe pattern by a least square algorithm, calculating a numerical value of a gamma correction factor of each pixel according to a relation between the amplitude and the gamma correction factor, correcting the original stripe pattern generated by the computer accordingto the gamma correction factor, and projecting the corrected phase shifting stripe pattern by adopting the three-dimensional measuring system to perform three-dimensional reconstruction.

An electrical processing network including a first set of ports and a second set of ports electrically coupled to the first set of ports. The first set of ports are for a first set of signals with approximately 0° and 180° relative phase. The second set of ports are for a second set of signals with approximately 0°, 90°, 180° and 270° relative phase.

The invention discloses a permanent magnet linear motor controller which controls a motor by means of a combination of an H-infinity robust controller, a ZPETC (zero phase error tracking controller) and an interference observer. The ZPETC is used as a feed-forward controller of a system and reduces phase errors by means of zero point elimination. The interference observer eliminates high-frequency interference signals by being provided with a low-pass filter. The H[sigma] robust controller utilizes a mixed-sensitivity design method, comprehensively considers balance between sensitivity and robustness, and sets the optimization of the parameters of the H-infinity robust controller by performing fuzzy judgment on the results of the ZPETC and the interference observer. The controller combining the above three methods optimizes the dynamic performance and the stable performance of a permanent magnet linear motor, and may effectively improve positioning precision, a response characteristic, and an anti-interference capability.