106results about How to "Achieve frequency" patented technology

The invention relates to an electric power system net rack reconstruction optimization method capable of considering a microgrid as a black-start power supply. The method comprises the following stepsthat: inputting electric power system parameters; taking the maximum recovery of the power generation capacity of the system and the minimization of a load loss amount in the microgrid as targets toconstruct a net rack reconstruction optimization model capable of considering the microgrid as the black-start power supply; determining the constraint condition of the net rack reconstruction optimization model capable of considering the microgrid as the black-start power supply; on the basis of a node importance degree and path recovery time, constructing a synthesis path evaluation index to optimize the recovery path of a unit to be recovered; and jointly combining a bee colony algorithm with a quantum theory to solve the model. A net rack reconstruction strategy which adopts the microgridwhich contains high-ratio renewable energy sources as the black-start power supply has certain feasibility and effectiveness. Under a situation that the conventional black-start resources of the system are insufficient, the microgrid can be taken as the black-start power supply to provide starting power for non-black-start units, and the non-black-start units can be quickly recovered to achieve apurpose of net rack reconstruction.

A reconfigurable antenna is arranged on one surface of a substrate and comprises a plurality of radiating bodies and a control circuit. The radiating bodies comprise a centre radiating body and a plurality of outer radiating bodies distributed in a regular geometrical shape with the centre radiating body as the center, and the control circuit is arranged among the radiating bodies and controls reconstruction of gains of the radiating bodies. The control circuit controls the radiating bodies so that electromagnetic radiation fields of the radiating bodies can be changed, frequency recombination and gain recombination are achieved, the antenna can be controlled through control signals to reduce frequency bands of the antenna and increase gains of certain frequency bands, and the antenna is cheap and easy to manufacture; obvious technical and cost advantages are achieved, the gains can be reconstructed when weak signals are caught, and reception capacity is enhanced.

The invention is concerned with the broad band microwave local-surge generator, it is: the vector-controlled oscillator creates low-voice high-frequency signal to the power divider, the phase-lock circuit, the loop filter in turn, then feedback to the vector-controlled oscillator in order to form the phase-lock loop signal source creating circuit that is the decimal fraction frequency division and reflecting-phase mixed-dispel suppression, the high-frequency signal creating by the circuit passes the frequency multiplier, the filter and the amplifier to get the signal source with different frequency that is needed by the microwave system. The invention can achieve the multi circuit local-surge creation on the veneer with lower cost.

The invention relates to a vibration testing system and method for a thin-wall cylindrical shell component, and belongs to the technical field of laser Doppler vibration measurement. A laser Doppler vibrometer, a test piece mounting table and a laser reflecting unit are all arranged on a base, and the laser emitting end of the laser Doppler vibrometer corresponds to the test piece mounting table. Guide rails and a lead screw of the laser reflecting unit are both fixedly arranged on a fixing support, sliding blocks are fixedly arranged on a sliding carriage, and the sliding carriage is in sliding fit with the guide rails through the sliding blocks. A nut is arranged on the lead screw in a sleeved mode, and the nut is fixedly connected to the lower surface of the sliding carriage. One end of a measurement arm is fixedly arranged on the upper surface of the sliding carriage, and the measurement arm, the lead screw and the guide rails are all arranged in parallel. A reflecting mirror is arranged at the other end of the measurement arm, a 45-degree included angle is formed between the reflecting mirror and the vertical direction, and the laser emitting end of the Doppler vibrometer corresponds to the reflecting mirror. A first drive motor is mounted between the reflecting mirror and the measurement arm, and an output shaft of the first drive motor is fixedly connected with the reflecting mirror. A second drive motor is arranged at the shaft end of the lead screw.

The invention discloses a high-frequency flutter cold extruding die, which comprises a forming mechanism. A male die is fixedly connected with an upper template; a female die is positioned under the male die and is arranged in a female die sleeve; a flutter generation mechanism comprises a vibration table and a high-frequency valve, wherein the vibration table comprises an upper plate and a lower plate; a lug boss is arranged in the middle of the upper plate and is fixedly connected with the female die sleeve; a vertically-symmetrical annular groove is arranged on the upper plate around the lug boss; the section of the annular groove is in an arc shape; a lower groove is arranged in the middle of the upper surface of the lower plate and is communicated with an annular groove on the lower surface of the lower plate; the upper plate is in fixed sealing connection with the lower plate through a fastener; the fastener is positioned at an outer circle of the annular groove; the lower plate is provided with an oil passage through which hydraulic oil enters or exits; one end of the oil passage is communicated with the lower groove; the other end of the oil passage is communicated with the high-frequency valve; and the lower plate is fixedly connected with a lower template. According to the high-frequency flutter cold extruding die disclosed by the invention, enough vibration output force, higher vibration frequency and lower amplitude can be provided; and dimensional precision of complex parts can be ensured while the vibrated extrusion of the complex parts are finished.

The invention discloses an integrated single-laser-source optical device for a movable cold atom interferometer, and the device comprises a laser source and a power amplification module which are usedfor generating single-frequency laser; a laser frequency stabilizing and adjusting module which is used for converting the single-frequency laser into seven laser frequencies required by the cold atom interferometer; a laser power stabilization, distribution and time sequence control module which is used for generating various lasers with specific frequency and power according to a time sequence;and a microwave source and electronics control module which is used for carrying out switching and time sequence control on all the modules, wherein the final output light is transmitted to the sensing head module of the atomic interferometer through the four polarization maintaining optical fibers. The device has the advantages of small volume, low power consumption, low cost, high stability andthe like.

This invention discloses a three-phase magnetic resistance motor, which replaces the multi-stage rotor core with a ladder-type convex pole with an ellipse two pole rotor core and utilizes a self-controlled light-coupled switch mounted on the axostyle of the rotor to realize location control and frequency self-support having the character of a self-controlled synchronous motor, and its unit volumepower reaches to over 4 times of the present one.

An apparatus for processing an audio signal to focus an acoustic signal by an arrangement of a plurality of loudspeakers comprises a frequency analyzer, a signal processor and a signal output interface. The acoustic signal is based on the audio signal. The frequency analyzer is configured to determine a fundamental frequency in a frequency spectrum of the audio signal depending on a geometry parameter of the arrangement of the plurality of loudspeakers. The signal processor is configured to adapt an overtone of the fundamental frequency to obtain the processed audio signal and the signal output interface is configured to output the processed audio signal to the plurality of loudspeakers.

The invention discloses a vehicle detector, a method for intermittent and variable-frequency power supply, and a method for reducing the power consumption of a wireless transceiver module, and relates to the technical field of vehicle detection. According to the vehicle detector provided by the invention, a microcontroller controls a power supply control chip through a power control pin to realize on-off and on-off frequency change of a magnetic resistance sensor and an ADC module and further realize intermittent and variable-frequency power supply to the magnetic resistance sensor. Thus, high-accuracy vehicle speed detection under high-frequency ADC sampling is ensured, and the situation in which waste of power is caused due to the adoption of high-frequency intermittent power supply when a vehicle has not arrived is avoided. According to the vehicle detector provided by an embodiment of the invention, the power consumption is reduced through intermittent power supply and variable-frequency power supply, and the accuracy of vehicle arrival detection signals is improved through variable-frequency power supply. In addition, by distributing the time length of timed data uploading to each vehicle detector, the power consumption of wireless transceiver modules is greatly reduced, and the battery life and the effective working time of the vehicle detectors are prolonged.

The invention provides a malicious code evidence obtaining method and system on the basis of a feature code under the Linux. The method extracts an accurate feature code through known malicious files and non-malicious files, carries out multi-mode matching on an unknown file and a WM (Wu-Manber) feature rule library after the features of the file under a Linux system is subjected to whitelist detection, carries out detection to obtain a detailed and accurate result, and gives a detection evidence obtaining report. The method also utilizes the characteristics that information including a registry, a starting item and the like in the Linux can be stored in a file form to extract starting item information, memory information, process information and the like, and can detect the information so as to detect the malicious files in the system.

An embodiment of the invention provides a data transmission method and a data transmission device. The data transmission method comprises the steps of: modulating information bits to be transmitted according to a lower-order constellation diagram to generate 4m lower-order modulation symbols; multiplying a precoding matrix Q with column vectors formed by the 4m lower-order modulation symbols to obtain 4m higher-order modulation symbols to be transmitted corresponding to a higher-order constellation diagram; and transmitting the 4m higher-order modulation symbols to be transmitted on different corresponding carriers of two antennas separately. The higher-order modulation symbols to be transmitted contain a part of or all of the information bits to be transmitted, and therefore, the same signal can be simultaneously transmitted on different carriers of a plurality of antennas, thereby achieving frequency diversity and space diversity, and accordingly improving the transmission and receiving performance of data transmission.

The invention discloses a method and device for measuring laser frequency stability. The method comprises the following steps of: selecting a periodic electric signal as a chirp control signal of a reading laser; setting the sampling time tau of the output frequency of a laser to be tested by adjusting the period T of the chirp control signal of the reading laser; calculating the mapping relationship f(t) between the output frequency and time of the reading laser to obtain the mapping relationship between the frequencies and time of spectral burnt holes; measuring the time corresponding to the spectral burnt holes formed by light signals to be tested output by the laser to be tested with nominal frequency f<c> to obtain the output laser frequency of the laser to be tested and then obtain the j frequency drift delta f<c>(j) in the sampling time tau; and carrying out statistics on the frequency drift to realize measurement of the frequency stability of the laser to be tested in the sampling time tau. By adopting the method and the device, the problem in the prior art that reference light sources with ultrahigh stability and small frequency difference with the laser to be tested are needed for measuring the laser stability is solved.

The invention provides a frequency adjustable band-pass frequency selective surface structure. The frequency adjustable band-pass frequency selective surface structure comprises a dielectric plate anda metal patch and a graphene patch which are arranged on the upper surface of the dielectric plate, wherein an annular slot is formed in the metal patch, the annular slot is internally provided withthe graphene patch in the shape of an annular ring, and the graphene patch is seamlessly laminated inside the annular slot; and a cross-shaped slot is formed in the middle of a circular area surrounded by the graphene patch. According to the frequency adjustable band-pass frequency selective surface structure provided by the invention, the frequency adjustable function under different frequenciescan be realized.

The invention relates to a tuning circuit and a tuning method of an on-chip filter. According to the tuning circuit and the tuning method, through inherent frequency phase response characteristics of the filter, the filter is connected into a closed loop in spare time, so as to perform self-excited oscillation, the frequency and the amplitude value of the self-excited oscillation of the filter are detected, and parameters of the filter are adjusted, so as to tune the frequency and the Q value of the filter. The tuning circuit has the advantages of simple structure and easiness in implementation, the influence of a conformity error and layout design of the CMOS (Complementary Metal Oxide Semiconductor) process on the tuning result of the filter is less, and the frequency and Q value tuning functions of the on-chip filter can be implemented at the same time.

The invention discloses a nonlinear metasurface based four-wave mixing holographic multiplexing method, and belongs to the micro nano holographic field. The method comprises that a metasurface is composed of an array with nanometer rectangular hole structures in different geometric sizes; the geometric sizes of the nanometer rectangular hole structures are changed, so that the nonlinear metasurface can randomly regulates the amplitude and phase of an output nonlinear frequency signal; complex amplitude distribution of the nonlinear light field output in different sizes can be obtained by fullwave vector calculation; an amplitude type hologram is calculated based on an optimized GS algorithm, and a bit coding method is used to code the hologram of the rectangular hole structure; rectangular hole structure distribution is determined by coding, and the corresponding nonlinear metasurface structure array is generated; and two beams of femtosecond pulses in different frequency are input torealize nonlinear holographic space and frequency multiplexing of the same nonlinear metasurface structure array. The method can be applied to the fields including signal processing, optical storage,high-dimensional holographic anti-counterfeiting and optical encryption.

The invention provides a dominant wave (DW) automatic frequency tracking numerical receiver. The numerical receiver not only has the function of radar numerical intermediate-frequency (IF) receiving, but also realizes numerical automatic frequency tracking and locking received by radar, and the system does not need traditional automatic frequency control loop circuits and external frequency adjustment components. The technical scheme of the invention is as follows: the IF DW and the IF echo wave channels of the receiver are received by wideband, the receiving bandwidth is determined according to the frequency coverage really needed by a radar system. The invention is mainly characterized in that the receiver carries out wideband sampling and buffers DW data received from the radar, the DW power spectrum is obtained by real-time numerical FFT transformation, the center of gravity of unilateral band spectrum is calculated, the frequency estimation of DW is obtained by the value of the center of gravity of spectrum and is converted into corresponding numerical control oscillator (NCO) frequency control word, the frequency control word obtained by calculation is used to control the frequency of NCO under synchronous trigger to realize automatic tracking of the DW frequency of NCO, AD sampling is carried out on the radar echo signal and then orthogonal down-conversion is carried out on the radar echo signal and the numerical frequency signal generated by NCO, the echo wave video IQ signal is obtained after IF matched filtering, and frequency adjustable components are only NCO. When DW frequency is calculated, the DW power is simultaneously calculated to judge whether the current DW input is valid or not, and if the DW is invalid, the search of system frequency is started. A timing sequence generating circuit generates AD sampling clock, generates DW sampling control sequence and data latching sequence according to trigger signals, and provides NCO clock.

The invention discloses an active balance control performance evaluation method based on electric power system reliability. The method comprises steps that safety frequency requirements are determined; adequacy frequency requirements are determined; evaluation indexes are designed. According to the method, a new adequacy index, namely frequency loss expect is constructed, a deviation degree and probability of electric power system frequency after an accident are quantitatively described to reflect influence of accident disturbance on power supply capability of an electric power system; adequacy and safety requirements of the electric power system are both considered, long-term (a range from a month to a year) and short-term (minute-level) time scales are employed, the accumulation off-limit time and the continuous off-limit time of the frequency are respectively limited, in combination with the safety adequacy index, through theoretical derivation, analysis expressions of the evaluation indexes are acquired, long-term and short-term frequency fluctuation situation situation requirements under a stable state are realized, and complete theoretical bases are realized.

The invention discloses a real-time measurement apparatus of microgram magnitude quality. The apparatus comprises an installation platform. An upper surface of the installation platform is provided with a non-contact displacement sensor. A weighing elastic sheet is suspended above the installation platform. A lower surface which is adjacent to the weighing elastic sheet is connected to a detection target block. A central axis of the detection target block, a central axis of the non-contact displacement sensor and a center position of the weighing elastic sheet are superposed. The invention also discloses a measurement method of the real-time measurement apparatus of microgram magnitude quality. By using the apparatus and the method of the invention, a problem that the microgram magnitude quality can not be measured in high frequency and high precision modes in real time in the prior art is solved.

The invention discloses a black-start comprehensive verification system of a power system and a method of the black-start comprehensive verification system. With the black-start comprehensive verification system, various technological verification problems of black start are solved on the same system platform, verification calculation results of overvoltage verification of a black-start scheme of the power system, voltage frequency verification during starting of an auxiliary machine and self-excitation verification are output by verification calculation of all contents such as overvoltage verification of the given black-start scheme, the voltage frequency verification during starting of the auxiliary machine and the self-excitation verification, and thus, whether the set black-start scheme of the power system is appropriate or not can be effectively determined; and meanwhile, by a friendly pattered human-computer interaction interface, the burdens of system model building and data input/output processing are reduced, result analysis and verification conclusion judgment are automatically carried out, the verification complexity and the working burden of the black-start scheme are greatly reduced, and an effective auxiliary tool is provided for making and revision of the black-start scheme.

The invention discloses a synchronous implementation method and a synchronous control device for a three-phase uninterrupted power supply (UPS) parallel operation system. The synchronous control device comprises a preprocessing circuit, a master control circuit and a parallel operation communication interface circuit; in the synchronous implementation method, the master control circuit samples and detects the voltage and current signals obtained by the preprocessing circuit, the phase, frequency and amplitude of the output voltage of the UPS inverter are regulated, and bypass/inversion logic control is realized; the parallel operation communication interface circuit is used for transmitting/receiving a synchronizing signal, a bypass/inversion control signal, an inverter state signal and a bypass phase-A voltage tracking signal. According to various different operation states of the UPS, the synchronizing signal is analyzed and integrated through a digital signal processor (DSP), a pulse width modulation (PWM) control signal is transmitted, and the frequency and the phase of each UPS output voltage in the parallel operation system are controlled, so that the high-precision synchronization of the frequency and the phase of each UPS output voltage is realized.

The invention relates to a horizontal two-degree-of-freedom electromagnetic vibration isolation device based on parallel connection of magnetic gravitational positive and negative stiffness, and belongs to the technical field of precision vibration isolation. An X-direction magnetic spring and a Y-direction magnetic spring are vertically arranged and connected in parallel to realize the parallel connection of a horizontal two-degree-of-freedom positive and negative stiffness structure. The X-direction magnetic spring is composed of a first fixed magnet, a first moving magnet, a second moving magnet and a second fixed magnet in an array along a horizontal X axis. The Y-direction magnetic spring is composed of a third fixed magnet, a third moving magnet, a fourth moving magnet and a fourth fixed magnet in an array along a horizontal Y axis. The horizontal two-degree-of-freedom electromagnetic vibration isolation device has the advantages that structure is simple and flexible, natural frequency is low, utilization rate of magnetic materials is high, and horizontal two-degree-of-freedom low-frequency/ultra-low frequency vibration isolation effect of precision instruments is realized.