13 results about "Distortion factor" patented technology

This invention discloses a method for amplitude and phase distortion correction in ISAR broadband direct sampling receivers. First, an amplitude and phase distortion echo signal model for the ISAR broadband direct sampling receiver is constructed. Matched filtering is applied to the amplitude and phase distortion echo signal at a single scattering point, and a fitness function is constructed based on the matched filtering results. Then, the PSO algorithm is used to iteratively optimize the amplitude and phase distortion coefficient vector of the echo signal at each scattering point, obtaining an estimated vector of amplitude and phase distortion coefficients, thus obtaining the amplitude and phase distortion estimates for the echo signal at each discrete point. Finally, an amplitude and phase compensation factor is calculated based on the estimated amplitude and phase distortion values ​​of the echo signal at the discrete points. This factor is used to correct the amplitude and phase distortion echo signal at each discrete point in real time, obtaining the corrected echo signal at each discrete point. The corrected echo signals at each discrete point are then superimposed to obtain the final corrected echo signal. This method solves the problems of insufficient targeting and easy getting trapped in local optima in high-dimensional solutions, thus improving ISAR imaging performance.

The present application relates to the technical field of roller shutter door assembly wear evaluation, and particularly relates to a silent roller shutter door assembly wear evaluation method based on vibration signal analysis, which comprises the following steps: collecting a roller shutter door vibration signal, performing wavelet packet decomposition, reconstructing a denoising signal according to energy entropy and kurtosis product, and generating a window adjustment coefficient; calculating a slope ratio to construct a double-threshold band scaled by the adjustment coefficient to determine candidate pulse points; dividing pulse clusters according to time interval mutations, extracting amplitude Gini coefficient, interval discrete entropy and center frequency offset to fuse into a distortion factor; constructing a wear characteristic vector from the distortion factor cumulative slope and peak interval ratio, determining a wear grade through Mahalanobis distance comparison; recursively updating a covariance matrix based on a forgetting factor, and performing a remaining service interval penalty compression measurement. The present application overcomes the strong noise masking problem and guarantees the reliability of the prediction result.

The invention belongs to the technical field of micro-ring modulator optimization, and particularly relates to a micro-ring modulator feedback control system for realizing optical modulation amplitude and linearity optimization. A low-speed PAM-4 test signal easy to process is generated through a test code generation module and is pre-distorted through a feedback control module to drive a micro-ring modulator, a signal acquisition module acquires a response signal of the modulator in real time, and an eye pattern calculation module extracts current light modulation amplitude and linearity of quantitative performance from the response signal and calculates the light modulation amplitude and linearity of the micro-ring modulator. And the feedback control module synchronously adjusts the working points of the micro-ring modulator based on the indexes to optimize the light modulation amplitude, and adjusts the pre-distortion coefficient to optimize the linearity, thereby solving the problems of performance compromise and power consumption increase caused by the separation of the light modulation amplitude and the linearity optimization in the prior art. Compared with the prior art, collaborative optimization is achieved, and energy efficiency is improved while performance compromise is avoided.

This invention discloses a dynamic frequency allocation method for wireless communication networks, belonging to the field of wireless communication processing technology. Through offline measurement and model identification, a quantitative relationship between the input signal of the preceding time slot and the nonlinear distortion at the current moment is established. Historical usage sequences of frequency bands and power are collected and stored in real time, providing the input signal characteristics of the preceding time slot for memory effect residual assessment. Combining the historical usage sequences with the memory effect model, the residual intensity of the memory effect in each frequency band is calculated in real time, providing a quantitative basis for frequency band scheduling. Protective time slots are set for high-residual frequency bands to avoid their use before the memory effect has completely disappeared. Low-residual frequency bands are preferentially allocated to high-power users through priority ranking. The memory effect residual of power amplifiers is compensated in real time by dynamically updating the predistortion coefficients. The predistortion coefficients are adjusted according to the preceding and current signal characteristics to ensure good predistortion performance in different operating scenarios.

The invention discloses a transformer winding deformation and turn-to-turn short circuit simulation fault feature diagnosis method, and relates to the technical field of power equipment winding fault detection. According to the transformer winding deformation and turn-to-turn short circuit simulation fault feature diagnosis method, high-fidelity simulation of winding deformation and turn-to-turn short circuit is realized through a mechanical structure, and oscillatory wave signals of a transformer winding under different fault conditions are obtained; according to different fault types, feature parameters of the fault types are extracted from five different dimensions, and fault type response weights and dynamic distortion factors are calculated; because the fault device contains many fault types, different fault types are simulated through the adjusting device, thereby influencing the change of the response weight of the fault types. And finally, obtaining a self-adaptive threshold comprehensive degradation degree. Accurate identification and degree evaluation of winding health state, turn-to-turn short circuit and deformation faults are realized.

The application discloses a digital pre-distortion compensation method based on a genetic algorithm, and comprises the following steps: acquiring a plurality of initial signal characteristics and initial pre-distortion coefficients; obtaining a first population and a second population according to the initial signal characteristics and the initial pre-distortion coefficients; processing the first population and the second population respectively by using a genetic algorithm to obtain a first lookup table and a second lookup table respectively; acquiring a corresponding first pre-distortion coefficient in the first lookup table according to a to-be-compensated baseband signal; when it is judged that the first pre-distortion coefficient meets a preset accuracy requirement, the first pre-distortion coefficient is used for compensation; or when it is judged that the first pre-distortion coefficient does not meet the preset accuracy requirement, a corresponding second pre-distortion coefficient is acquired in the second lookup table, and the second pre-distortion coefficient is used for compensation. By setting the first lookup table and the second lookup table, different rules are used for lookup table searching of signals with different requirements, and the pre-distortion compensation efficiency and accuracy can be further improved.

This invention relates to the field of optical imaging testing, and more particularly to a camera field of view testing device and method. The method includes first acquiring a calibration image and a test image; calibrating the distortion parameters of the vehicle-mounted camera using the calibration image; and using these distortion parameters to correct the distortion of the subsequent test image used for field of view calculation, resulting in a distortion-free test image. On the distortion-free test image, the full field of view of the camera under test is calculated based on angle markings with known angle values. This invention innovatively employs a calibration-correction-calculation approach to test the camera's field of view, fundamentally eliminating the influence of distortion factors on the measurement results, achieving a breakthrough in technical principles, and thus improving the accuracy of field of view testing.

A control unit for a switching converter operating in continuous conduction and peak current control mode. The control unit has an inductor element coupled to an input and a switching element coupled to the inductor element, generates a command signal having a switching period to switch the switching element, and determines a first time period in which an inductor current flows in the inductor element for storing energy and a second time period in which energy is delivered to a load. The input current is distorted with respect to a sinusoidal curve by a distortion factor caused by a current ripple on the inductor current. A duration of the first time period is determined based on a comparison between a value of a peak of the inductor current and a current reference dependent on an output voltage of the voltage converter. A reference modification stage modifies the current reference to compensate for the distortion introduced to the input current by the distortion factor.

The invention discloses a signal correction method for a pulse type terahertz system, and relates to the technical field of terahertz waves. After frequency spectrum data of terahertz signals are obtained through a terahertz waveform standard device, a distortion coefficient is calculated, frequency domain data, obtained in a terahertz system, of the terahertz signals are corrected through the distortion coefficient, and then undistorted terahertz time domain waveforms are obtained through inverse Fourier transform. The problems that in a current pulse type terahertz system, the inherent influence elimination cost of the system is high, and signals are prone to distortion are solved.

A digital pre-distortion achieving near ideal spectral regrowth suppression with a bandlimited loopback. To eliminate mismatch between the bandwidth of the pre-distortion model terms and the bandwidth of the signal used to determine the model a band limiting operation may be applied to both the loopback signal and the input to the power amplifier used for estimating the pre-distortion coefficients. In addition, oversampling may be performed in the digital domain to avoid aliasing in the nonlinear terms of the pre-distortion model.

Systems and methods are disclosed for utilizing frequency multiplier (FX) based transmitters to generate wideband, substantially distortion-free signals, when a transmitter operates under bandwidth constraints. A receiver is configured to acquire the feedback signal at the multiplier output. The systems and methods alleviate the bandwidth constraints of the receiver. Additionally, the invention includes a training methodology for estimating predistortion coefficients configured to operate under constrained transmitter and receiver bandwidth conditions.

The invention belongs to the technical field of data processing of the computer information disciplinary, and relates to a broadband power amplifier linearization method and system based on predistortion, and the method comprises the steps: collecting and preprocessing a radio frequency input baseband signal, an actual output baseband signal and tube core heat flow data of a broadband power amplifier, and obtaining an initial data set; calculating a transient heat dissipation gradient at each sampling moment based on the signal energy difference and the tube core temperature change rate; in combination with broadband distribution characteristics of radio frequency input baseband signals, broadband thermal teratogenesis factors at all sampling moments are obtained; performing dynamic tracking compensation on a cross term coefficient of a generalized memory polynomial based on the distortion factor to obtain an update coefficient; and the pre-distortion signal is reconstructed by utilizing the updating coefficient, so that high-linearity output of the broadband power amplifier is realized. The dynamic response speed of coefficient updating can be improved, thermally induced nonlinear distortion of a power amplifier is effectively offset, and the linearity and stability of a high-power broadband radio frequency test are improved.