485 results about "Harmonic interference" patented technology

The invention discloses a full-wave nuclear magnetic resonance signal denoising method based on independent component analysis. The full-wave nuclear magnetic resonance signal denoising method is mainly used for power frequency harmonic interference or certain single-frequency interference in full-wave nuclear magnetic resonance signals. The method comprises the steps that firstly, utilizing a nuclear magnetic resonance sounding water detecting instrument for collecting MRS signals, obtaining the frequency of power frequency harmonic interference or certain single-frequency interference contained in the collected signals through spectral analysis, and adopting a digital orthogonal method for constructing input channel signals to solve the underdetermined blind source separation problem; then, using the constructed input channel signals and the collected MRS signals as input signals for conducting independent component analysis to obtain separated MRS signals; finally, adopting the spectrum correcting method for solving the problem that the separated MRS signals have uncertain amplitude, and then extracting denoised MRS signals. According to the full-wave nuclear magnetic resonance signal denoising method, the problem of the underdetermined blind source and the problem of the uncertain amplitude usually existing in independent component analysis are solved, the power frequency harmonic interference or the certain single-frequency interference in the noised MRS signals is effectively filtered out, and compared with a traditional MRS signal denoising method, the full-wave nuclear magnetic resonance signal denoising method has the advantages of being high in arithmetic speed, high in signal to noise ratio, high in practicability and the like.

A dual conversion receiver selects and down-converts one channel from a plurality of channels in a received RF signal. The dual conversion receiver includes first and second mixer stages that are driven by first and second local oscillator signals. Channel selection is performed by tuning the first local oscillator signal so that a desired channel is up-converted to a first IF frequency, which defines the center of the passband of a first bandpass filter connected between the first and second mixer stages. The second mixer stage down-converts the output of the first bandpass filter to a second IF frequency, which is further filtered by a second bandpass filter. The first and second local oscillators can produce harmonics that mix in the second mixer stage, causing unwanted spurious signals that can fall in band with the second IF frequency. In order to avoid interference from these unwanted spurious signals, the frequency step size of the first local oscillator is tuned so that the spurious signals fall out-of-band of the second IF frequency.

The invention discloses a nuclear magnetic resonance underground water detection signal noise eliminating method. The method comprises the steps of: recoding response data entry three groups, each of these three sets of data Fourier transform nuclear magnetic resonance to determine the frequency of the data center in each neighborhood contains frequency harmonics, and frequency harmonic structure and the same frequency, and magnetic resonance corresponding data with sine function of the length of the cosine function, and composition and magnetic resonance response data observed signal using independent component analysis for each group observed signals to separate the mixed signal obtained solution for data reconstruction to eliminate frequency harmonic interference, the three groups of removing harmonic frequency data as observational signals, and then use algorithm processing, weaken the remaining random noise. The invention is to eliminate harmonic frequency noise at the same time, the signal will not destroy any details, without laying a reference coil, simple operation, suppress random noise does not require a lot of data, reducing the processing time.

The invention relates to the field acquisition field of earth physical exploration, in particular to a multi-factor scanning method of a controllable vibroseis. The method comprises the following steps of: exciting an earthquake wave with a wide-frequency scanning signal to finish acquisition; selecting a receiving channel to make an amplitude spectrum and a frequency division scanning field; decomposing the signal to create a group of sub-scanning with different start frequency and end frequency for spectrum superposition and factor superposition and comparing the superposed spectrum with practical data to confirm a sub-scanning group; combining sub-scanning for field acquisition, carrying out the frequency division scanning of the amplitude spectrum, comparing amplitude spectrum data and frequency division records to confirm the best sub-scanning factor and mapping. The invention can reduce the correlated sidelobe of data, improve the signal-to-noise ratio of the data, effectively restrict harmonic interference, lessen the blindness of tests, improve the data quality and save exploration expenditure.

The invention discloses a multiple-input multiple-output antenna transmitting-receiving circuit, and the circuit comprises a radio frequency transmitter and a plurality of transmitting-receiving units. Each transmitting-receiving unit comprises an antenna, a power amplifier, a low-noise amplifier, a first switching unit, and a second switching unit. The power amplifier is used for the power amplification of a to-be-transmitted signal outputted by the radio frequency transmitter, so as to transmit the to-be-transmitted signal. The low-noise amplifiers are used for the amplification of radio frequency signals received by the antennas, so as to transmit the radio frequency signals to a radio frequency transceiver. The first switching units and the second switching units are used for switching a transmitting path according to the transmitting-receiving state of the radio frequency transceiver. The circuit is additionally provided with the switching units so as to achieve the switching of the transmitting path, thereby achieving the isolation of the transmitting path with a receiving path, effectively inhibiting harmonic interference generated between the transmitting path and the receiving path, and improving the isolation degree of adjacent antennas.

The invention is applicable to the technical field of electric variable sampling measurement, and provides an industrial frequency interference resistant signal sampling method and a system. The method comprises the following steps: step A. extracting industrial signals from input commercial power alternating-current signals, synchronously tracking industrial interference signals superposed on detection signals through industrial frequency signals, and generating an industrial frequency synchronous signal; and step B. locking a zero crossing phase of the industrial frequency interference signals according to the industrial frequency synchronous signals, and synchronously sampling the input detection signals at the zero crossing phase. The invention realizes the synchronous sampling of thedetection signals at the zero crossing phase by synchronously tracking the industrial frequency interference signals; and compared with the wave traps or filter technique, the embodiment of the invention can furthest reserve effective components in the detection signals while eliminating the industrial frequency interference, has simple algorithm realization, and little source and time consumption, and can real-time track the industrial frequency interference.

Systems and methods are disclosed for disposing high and low-resistivity portions of semiconductor substrate in proximity to an active radio frequency (RF) device, thereby at least partially controlling harmonic interference associated with the device. The device may be disposed above the high-resistivity portion, and at least partially surrounded by the low-resistivity portion. The high and low-resistivity portions may provide various benefits associated with interference attenuation, thermal properties, or other benefits. The low-resistivity region can be disposed an optimized distance away from the device.

The invention discloses a control method and power supply device for an electron-beam welding machine to accelerate high-voltage power supply, which uses three-phrase commercial power and adopts the current transformation mode of AC-DC-AC-DC; wherein, the inversion link DC-AC in the middle is medium-frequency inversion; the function of high frequency pulse width modulation and voltage regulation is realized in the inversion process; the transmission of the electrical energy, the transformation of the voltage value and high voltage insulation are realized by a medium frequency high voltage transformer; by using a high voltage sampling signal as an inverse feedback signal to control the duty cycle of the high frequency pulse width modulation output wave, the automatic stable regulation of the output high voltage is realized. Therefore, the device is characterized by little harmonic interference in the power network, quick system regulation, small output high voltage ripple, simple manufacturing and higher efficiency.

The invention relates to the field of noise filtering of nuclear magnetic resonance sounding signals, particularly to a method for filtering full-wave nuclear magnetic resonance signal noises based on double singular value decomposition. The method comprises: colleting one group of observation MRS noise-included data by using ground nuclear magnetic resonance underground water detection equipment; carrying out band-reject filtering using a Larmor frequency as a center on the data to realize preliminary signal and noise separation; carrying out first singular value decomposition and reconstructing noise data; subtracting the reconstructed noise data from the observation MRS noise-included data to obtain data including most of signal energy and reduced noise energy; carrying out secondary t singular value decomposition and reconstructing an MRS signal that need to be extracted; and carrying out MRS signal feature parameter extraction by using a non-linear fitting method. For full-wave MRS data collected by a single channel, influences of power-frequency harmonic interference and random noises can be eliminated simultaneously; and effective extraction of the MRS signal feature parameters can b realized by non-linear fitting.

The embodiment of the invention provides a PWM (Pulse-Width Modulation) rectifier controlling method and a PWM rectifier. The PWM rectifier controlling method is a passivity control method based on repeated control and compensation, and comprises the following steps: a control law of the PWM rectifier based on the interconnection and damping configuration of port controlled dissipation Hamilton models is obtained with a Lagrange-Charpy integral method; and a composite controller including repeated control and passive control is used as a controller of the PWM rectifier, and the passive control is compensated by the repeated control according to the control law so as to suppress periodic interference. According to the embodiment of the invention, PWM rectification of a unit power factor can be realized, and at the same time the harmonic interference of a power grid is better suppressed under the condition of not detecting load harmonic current so as to improve power quality. Compared with the conventional PWM rectifier, the PWM rectifier disclosed by the invention has the functions of harmonic suppression and reactive compensation under the condition of not increasing hardware cost.

The invention particularly discloses a method for extracting surface nuclear magnetic resonance signals on the basis of power-frequency harmonic modeling and self-correlation. The method includes steps of (1), acquiring a group of MRS (magnetic resonance sounding) noised data by the aid of surface nuclear magnetic resonance groundwater detecting instruments; (2), judging whether spike noise exists or not by the aid of a statistic process, removing the spike noise if the spike noise exists, substituting an interpolation result for the spike noise, and keeping the measurement data unchanged if the spike noise does not exist; (3), using a harmonic modeling process to remove power-frequency harmonic noise from the data after the spike noise is removed from the data; (4), carrying out self-correlation and superposition processing on the result obtained in the step (3) to reduce random noise; (5), extracting MRS signal parameters from the result obtained in the step (4). The method has the advantages that the problem of difficulty in effectively extracting MRS signals due to strong power-frequency harmonic interference and random noise in magnetic resonance depth measuring water exploration work can be solved by the aid of the method, and the fitting errors of the key feature parameters of the acquired MRS signals are small.

Systems and methods are described for increasing the effective dynamic range of a digital data stream in a software-defined radio receiver. In one system the sample rate of an analog to digital (“A/D”) conversion process is adjusted dynamically to shift harmonic signal interference induced by the A/D conversion process to outside the channels of interest. In another system the sample rate of an A/D conversion process is constant and the frequency of a dynamically controlled local oscillator in a frequency translator is adjusted dynamically to shift harmonic signal interference induced by the A/D conversion process to outside the channels of interest.

The invention relates to a broadband multifrequency electric capacity unified measurement analysis system and implementation method. The system includes at least one electric capacity measuring device and a data storage and analysis host, the electric capacity measuring device acquires the power grid data at high frequency, and the data storage and analysis host receives the power grid data transmitted by the electric capacity measuring device for storage and meanwhile analyses, displays and forwards the received power grid data and transmits the data analysis result; the data storage and analysis host includes a network module for data storage and information exchange of multiple electric capacity measuring devices in the substation; and the electric capacity measuring device is arranged in the substation spacing layer, and the data storage and analysis host is arranged in the substation control layer. The system solves the problem that the measurement technology in the prior art cannot carry out the comprehensive and accurate measurement for the new characteristics of increasingly frequent harmonic interference and subsynchronous oscillation of a conventional power grid due to high-voltage DC power transmission technology, FACTS technology, and new energy large-scale access.

The invention relates to a method for monitoring electric network frequency, which is realized by the following steps of: (A) calculating voltage signals of A, B and C three-phase voltage subjected to mutual inductor conversion: U=UA+UB-UC; (b) performing the low-pass filtration of the calculated result signal U; and (C) measuring the frequency of the filtered signal. The method has the advantage that a monitoring device can still normally finish the function of measuring the electric network frequency under the conditions of any phase failure and harmonic interference.

The present invention discloses an anti-harmonic interference device of carrier aggregation, an antenna device and a mobile terminal. The anti-harmonic interference device comprises a power amplifier, a switching unit, a control unit, a first diplexer and a second diplexer. The first diplexer and the second diplexer are connected with accesses of a first frequency band and a second frequency band respectively, the frequency of a downlink signal of the first frequency band and the frequency of a secondary harmonic of an uplink signal of the second frequency band are overlapped, and the switching unit is connected with the control unit. When the first frequency band is used as a slave cell frequency band, and the second frequency band is used as a master cell frequency band, the switching unit switches an interface for outputting the first frequency band in the power amplifier to be connected with a harmonic consumption end used for consuming the secondary harmonic, otherwise, the switching unit switches the interface for outputting the first frequency band in the power amplifier to be connected with the first diplexer. According to the scheme of the present invention, the simple structure and the low cost are realized while the harmonic interference in the carrier aggregation is eliminated.

The invention discloses a power supply test system of output energy DC side feedback, including an equipment (3) to be tested, the test system includes a PFC power factor correction module (1), an AC or DC power supply module (2), an energy collecting module (4) and an energy feedback module (5); high-voltage DC bus of the PFC powerfactor correction module (1) is respectively connected with input terminal of the AC or DC power supply module (2) and output terminal of the energy feedback module (5); output terminal of the AC or DC power supply module (2) is connected with input terminal of the equipment (3), input terminal of the energy collecting module (4) is connected with output terminal of the equipment (3), output terminal of the energy collecting module (4) is connected with input terminal of the energy feedback module (5). Applying the system can improve energy recycling efficiency and reduce harmonic interference to power system greatly.

The invention discloses an improved current loop control method for a photovoltaic grid-connected inverter, and belongs to the technical field of solar photovoltaic power generation. The method comprises the following steps that: a voltage feedforward control quantity u1 is obtained through commercial electricity voltage feedforward; 2, a current error [delta]i is obtained through a voltage outer loop control structure; 3, the current error [delta]i is segmented for forming a plurality of current error segments, each current error segment adopts different gains, and a current equivalent voltage duty ratio control quantity u2 is obtained after the current passes through a current inner loop control structure adopting a controller P; and 4, a command value u_order of a switch comparison register is obtained. The control method provided by the invention has the advantages that the realization is simple; complicated integral and differential coefficient setting is not needed; the introduction of virtual orthogonal signals is not needed; time-consuming dp coordinate transformation is avoided; meanwhile, the output current distortion can be effectively reduced; and the resistance capability on electricity grid distortion and harmonic interference is enhanced.

The invention relates to a frequency chosen of singular-spectrum analysis-based magnetic resonance sounding signal extraction method. According to the method, a nuclear magnetic resonance sounding water detector is used to collect MRS signals of a Larmor frequency-known region; a broadband band-pass filter is adopted to suppress partial noises, and thereafter, the position of MRS signals corresponding to the Larmor frequency are found on a power spectrum based on power spectrum analysis; and frequency chosen of singular-spectrum analysis is performed, so that the MRS signals are extracted. Thefrequency chosen of singular-spectrum analysis includes the following four steps that: embedding is performed; RSVD (Regularized Singular Value Decomposition) is performed; and corresponding singularvalues are selected according to the amplitudes of the MRS signals so as to perform matrix reconstruction; and diagonal averaging is performed. With the method of the invention adopted, random noises, spike noises and power frequency harmonic interference can be effectively filtered from noise-containing MRS signals; and the effective extraction of the MRS signals under a complex strong noise interference condition can be realized. Compared with a traditional MRS signal de-noising method, the method has the advantages of high operation speed, high signal-to-noise ratio, high practicality andthe like.

The present invention provides a method for eliminating harmonic interference in controllable earthquake source earthquake exploration. The method comprises the following steps of: firstly extracting a focal force signal, or acquiring the focal force signal through the weight of a heavy hammer and a plate and acceleration of them; then using the focal force signal to calculate a ratio of each subharmonic component and a fundamental signal amplitude spectrum, and calculating a predictive filtering operator; utilizing the predictive filtering operator to carry out filtering processing on a seismic channel record, and estimating a harmonic component of each channel; finally, subtracting the predicted harmonic component from an uncorrelated seismic channel record to achieve a purpose of eliminating the harmonic interference. According to the invention, a correlated channel record can be processed, processing can be carried out in a time domain, the processing also can be carried out in a frequency domain, near channel data can be processed selectively, a whole canon record also can be processed, the method is flexible and convenient, processing efficiency is high, and a requirement of present field collection can be satisfied.

Provided are a method for processing harmonic interference, and a base station. The method comprises: before resource scheduling is conducted on a user equipment, determining, by a base station, whether a harmonic of an uplink frequency resource which is to be used by the user equipment in a current carrier aggregation scenario will generate harmonic interference to a downlink frequency resource which is to be used by the user equipment; if it is determined that the harmonic interference will be generated, acquiring a transmitting power of the user equipment and a relative energy value of a harmonic component of the uplink frequency resource which is to be used by the user equipment and a principal component, and also being capable of acquiring the channel state quality of the user equipment, and according to the acquired information, determining a change value of the reference signal receiving quality of the user equipment subjected to the harmonic interference; and if the change value of the reference signal receiving quality of the user equipment subjected to the harmonic interference exceeds a preset threshold value, adjusting a scheduling solution of the user equipment. The embodiments of the present invention reduce the interference of harmonic interference when the user equipment receives signals.

The invention belongs to the technical field of electric power signal analysis in electric power systems, and particularly relates to a zero point judging method based on electric power system sampling signals. An electric power signal zero crossing point detection method is mainly characterized by being capable of correcting errors of zero point judgment by high frequency harmonic interference, optimally selecting real zero crossing points, removing jump points and restraining errors caused by voltage and current events. Through a series of scientific and accurate methods, zero crossing points of electric power sinusoidal signals can be selected step by step.

A signal denoising method for a frequency-scan ion trap mass spectrometer includes reading a signal raw data array observed in the spectrometer. The signal raw data array is processed by Boxcar averaging method to obtain a first signal array. Then the first signal array is processed by a harmonic interference cancellation method to obtain a second data array. Next the second signal array is processed by a radio frequency interference reduction method and a third signal array without the background induced from driving voltage of ion trap is reconstructed according to the second signal array.