25 results about "Eigen frequency" patented technology

A method of determining residual intensity noise (RIN) of a sensor may comprise determining a first amplitude of a first harmonic of the sensor while a signal propagating through the sensor is modulated at a modulating frequency corresponding to twice an eigenfrequency of the sensor. The method may further comprise determining a second amplitude of a second harmonic of the sensor while the signal propagating through the sensor is modulated the modulating frequency, and determining the RIN of the sensor as a ratio of the first amplitude and the second amplitude.

The present disclosure relates to a method for monitoring a power device. The method includes obtaining at least one frequency spectrum of at least one physical component of the power device, wherein the at least one frequency spectrum comprises at least one eigenfrequency of the at least one physical component of the power device; measuring, using at least one sensor, a vibroacoustic signal of the power device; and determining a signal contribution of the at least one physical component of the power device to the vibroacoustic signal based on the obtained at least one frequency spectrum. The present disclosure also relates to a respective monitoring device and a system including at least one sensor and a monitoring device.

The present invention relates to the field of wireless power transmission technology, and specifically discloses a real eigenstate targeted magnetic energy control method based on multi-mutual inductance ratio front-end detection and positioning. First, a voltage regulating circuit is added between a DC power supply and each inverter circuit, and then the mutual inductance ratio is calculated by obtaining two transmitting loop currents by exciting the system twice, and then the voltage regulating circuit is adjusted according to the mutual inductance ratio, and then the eigenfrequency of the system is determined by frequency scanning, so that the system can select the corresponding eigenfrequency for excitation according to the mutual inductance ratio and charging demand. This method does not require the front-end transmitting coil to communicate with the back-end receiving coil, the time for identifying the mutual inductance ratio is short, and the complex calculation process during the eigenstate frequency detection is eliminated, which greatly reduces the difficulty of identifying the eigenfrequency value and simplifies the complexity of the system. This method accurately controls the energy transmission mode of the targeted magnetic energy, which can not only ensure the transmission efficiency of the system, but also ensure the output power of the system.

The application discloses a pump-probe method for measuring and regulating the dynamic behavior of a magneto-mechanical system, and belongs to the pump-probe technical field. A specific frequency sinusoidal magnetic field is used to pump a magnetostrictive resonator, and a variable frequency magnetic field weaker than the pumping magnetic field is used for detection. The magnetostrictive resonator comprises a rectangular resonator and a double circular resonator. For the rectangular resonator with multiple eigenfrequencies, the pumping magnetic field is applied on the low-order mechanical mode to regulate the stiffness of the resonator, and then the high-order eigenmechanical mode is tuned. For the double circular resonator with two coupled mechanical modes, the pumping magnetic field with a frequency equal to the frequency difference between the two coupled mechanical modes induces AT splitting. The application lays a foundation for precise regulation in the magneto-mechanical system. The application has the advantages of high precision, remote operation, simple structure, fast test speed, low cost and the like, and can be widely used for measuring the linear and nonlinear dynamic behavior of the magneto-mechanical system.

The present invention discloses a vibration absorbing device of a slender structure and a calculation method of its energy band structure. The vibration absorbing device is an elastic metamaterial with an energy band structure. The vibration absorbing device includes a plurality of periodically arranged primitive cells, which are composed of a spider web resonator and Kevlar tethers on both sides thereof. When calculating the energy band structure, a finite element model of the primitive cell is established based on the absolute node coordinate method. The relationship between the node coordinates and the global position vector of any point in the unit is obtained by using the shape function. The dynamic equation of the system is calculated by the unit strain energy and mass matrix. The Bloch boundary condition is added, and the real part and the imaginary part of the displacement field are separated by combining the Euler formula. The real part and the imaginary part of the displacement field are simulated by the finite element model respectively, and the dispersion curve cluster of the eigenfrequency with respect to the wave vector is obtained, and then the band gap of the energy band structure of the vibration absorbing device is obtained. The present invention adopts the above-mentioned vibration absorbing device, combines the elastic metamaterial with the passive shock absorber, and can be applied to the space tether system.

The application discloses a kind of low-frequency noise detection methods of optically pumped laser, it is successively including multi-link synchronous acquisition and working condition insertion preparation, subzone association determination and three reference contribution solution, eigen noise reconstruction and robustness constraint, unified spectrum output and parameter backwrite closed loop, it is related to laser noise detection technical field, by simultaneously obtaining main test signal, pump reference signal, environmental reference signal and background reference signal, and according to frequency band determination reference participation condition, respectively pump contribution, environmental contribution and background contribution are calculated, eigen low-frequency intensity noise spectrum and eigen frequency noise spectrum are reconstructed, then unified result is output in combination with residual check, freeze back and splicing constraint.The method can improve low-frequency noise source distinguishing ability, result continuity and working condition adaptability.

The invention discloses a hot-pressing resistance PT symmetrical micro-mechanical temperature sensor, which comprises two micro-mechanical resonators with the same structure, namely a first resonator and a second resonator, the two resonators are connected by a group of coupling spring beams, and two ends of the resonators are fixed on a substrate through anchor areas. A layer of aluminum film is deposited below the substrate of the second resonator, and the two anchor areas of the first resonator are connected with a constant current source to form hot-pressing resistance feedback. A first resonator with hot resistance feedback and a second resonator without feedback form a PT symmetric system, and the system is arranged at an Exception Point (EP) point. When the temperature changes, the aluminum material below the second resonator substrate deforms due to the high thermal expansion coefficient, the second resonator substrate is bent, the positions of anchor areas at the two ends of the second resonator are changed, the rigidity of the second resonator is changed, asymmetric disturbance is introduced into the system, the original PT symmetry of the system is destroyed, and the temperature of the system is reduced. The system eigenfrequency is split into two parts from one original frequency, and the frequency splitting amount corresponds to the temperature change. As the EP point has large response to tiny disturbance, the micro-mechanical temperature sensor with symmetrical thermal resistance PT can detect tiny temperature change and has high sensitivity.

The invention provides a method and a system for exciting an MEMS resonance module, the provided MEMS resonance module at least has a high-frequency mode and a low-frequency mode which are designed according to a target frequency integer ratio, a parametric excitation signal is applied to the MEMS resonance module to excite the low-frequency mode, the parametric excitation signal is a frequency signal with continuously changing frequency, and the frequency of the parametric excitation signal changes continuously. The eigenfrequency of the parameterized excitation signal is obtained, the eigenfrequency is the frequency of the parameterized excitation signal when the ratio of the first actual measurement frequency of the high-frequency mode to the second actual measurement frequency of the low-frequency mode is the target frequency integer ratio, the first actual measurement frequency is the frequency of the low-frequency mode in the excitation process of the parameterized excitation signal, and the second actual measurement frequency is the frequency of the parameterized excitation signal in the excitation process of the low-frequency mode. The second actual measurement frequency is the frequency of the high-frequency mode in the excitation process of the parameterized excitation signal, a target excitation signal is applied to the MEMS resonance module, and the frequency of the target excitation signal is the eigenfrequency, so that the energy transfer efficiency between different modes of the MEMS resonance module is improved, and the sensitivity of the MEMS resonance module is improved by integer multiples.

The invention discloses a method and a device for measuring the morphological oscillation eigenfrequency of an electrostatic suspension metal droplet, and relates to the field of liquid metal thermophysical parameter measurement, the method comprises the following steps: determining the instantaneous amplitude for each oscillation image under each excitation frequency, performing Fourier transform and fitting on the instantaneous amplitude of each oscillation image, and obtaining the morphological oscillation eigenfrequency of the electrostatic suspension metal droplet. The form oscillation frequency and amplitude of the metal liquid drops under the current excitation frequency are obtained; drawing forward and reverse morphological oscillation amplitude-frequency curves according to the morphological oscillation frequency and amplitude under each excitation frequency; according to the method, the metal droplet form change is comprehensively analyzed, the form oscillation process is subjected to datamation processing, the problem that resonance is not accurately judged through visual inspection of the metal droplet is avoided, the mean value of the forward oscillation frequency and the reverse oscillation frequency serves as the metal droplet form oscillation eigenfrequency, and the accuracy of the metal droplet form oscillation eigenfrequency is improved. The hysteresis effect is fully considered, and high-precision eigenfrequency measurement is realized.

A modular soundproofing device comprises at least one non-porous plate-shaped soundproofing element (102) having a first bending eigenfrequency of >50 Hz. At least one stiffening element (106) is mechanically coupled to each soundproofing element (102) to form a closed force loop surrounding the entire perimeter of the soundproofing element. A first bending eigenfrequency of the stiffening element (106) equals or exceeds that of the soundproofing element (102). Further, a viscoelastic interlayer is interposed at every mechanical joint between the soundproofing element (102) and the stiffening element (106). By varying the number, geometry, or spacing of the elements and stiffeners, structural stiffness, surface mass, and acoustic response are precisely tuned. The system delivers high airborne and structure-borne attenuation, particularly from 20 Hz to 200 Hz, with markedly lower surface mass than conventional mass-law solutions and can be incorporated into walls, floors, or ceilings using rigid or elastically decoupled mountings.

The present application belongs to the technical field of accelerometer second-order system identification, and specifically discloses an online parameter identification method for an accelerometer system based on a digital phase-locked loop, comprising: in a first displacement signal detection stage, applying a first excitation signal to a mass block in the accelerometer through electromagnetic excitation, detecting the first displacement signal of the mass block, and determining the phase difference between the first displacement signal and the first excitation signal as a reference phase difference, wherein the frequency of the excitation signal in the first displacement signal detection stage is fixed within a preset frequency range; in a second displacement signal detection stage, detecting the second displacement signal of the mass block and tracking the target phase difference through a digital phase-locked loop, wherein the target phase difference differs from the reference phase difference by a factor of #imgabs0#, and the frequency of the excitation signal in the second displacement signal detection stage is greater than a preset frequency upper limit; after the phase-locked loop stabilizes, determining the eigenfrequency and quality factor of the accelerometer. The present application enables quick online parameter identification of the accelerometer system.

The present invention discloses a method for measuring the amplitude-frequency response of a submicrowave signal in an extreme temperature-varying system, specifically relating to the field of quantum precision measurement technology. The method comprises the following steps: Step 1: calibrating the intrinsic frequency-longitudinal field DC intensity of a quantum bit; Step 2: selecting a suitable longitudinal field DC bias point; Step 3: determining the gate parameters at the longitudinal field DC bias point; Step 4: measuring the frequency shift introduced by the modulated longitudinal field using a Ramsey waveform; Step 5: varying the frequency of the alternating longitudinal field signal and repeating Step 4 to obtain an amplitude-frequency response characteristic curve. All signal transmission and measurement in the present invention are performed at room temperature, meeting the operating temperature range of general arbitrary waveform generators and microwave sources, making it easy to implement.

The invention provides a double-resonance self-adaptive locking method and device for a 355 nm single-frequency ultraviolet laser, and belongs to the technical field of lasers, and the method comprises the steps: scanning a sum frequency cavity in a preset cavity length range, and obtaining an initial cavity length range of the sum frequency cavity; the cavity length of the sum frequency cavity is adjusted within the initial cavity length range until the 532 nm fundamental frequency light and the eigenfrequency of the sum frequency cavity enter a resonance state, the cavity length is locked at the moment, and the 532 nm fundamental frequency light is locked to the sum frequency cavity; and adjusting the temperature of the nonlinear crystal in the sum frequency cavity until the 1064nm fundamental frequency light and the 532nm fundamental frequency light resonate, locking the temperature of the nonlinear crystal at the moment, and locking the 1064nm fundamental frequency light to the sum frequency cavity. According to the invention, the initial cavity length range is firstly determined to reduce the resonance search range, the automatic locking of the resonance condition is realized through the independent adjustment of the PZT and the TEC, the double resonance enhancement and stable matching of the two paths of base-frequency light and the sum-frequency cavity are realized, and the long-term stable output of 355 nm single-frequency ultraviolet laser is improved.

A phase modulation signal generating device for a fiber-optic gyroscope includes a sine wave generating part and a superimposing part. The sine wave generating part generates a fundamental sine wave of an odd-order frequency (v=(2n+1)Ve, where n=0, 1, 2, . . . ) of the eigenfrequency (Ve) of the fiber-optic coil and a higher-order sine wave of an odd-order harmonic frequency ((2m+1) v, where m=1, 2, 3, . . . ) of the odd-order frequency (v). The superimposing part superimposes the fundamental sine wave and higher-order sine wave generated by the sine wave generating part at a ratio using a modulation index optimized according to a noise target to be minimized and outputs the resultant signal as a phase modulation signal.

The frequency self-adaptive vibration energy collector for wireless intelligent sensing comprises a vibration frequency conversion assembly, a main vibrator, a power conversion assembly, a vibration frequency sensing assembly and an energy collection assembly.

The invention discloses a wireless passive sensing system and method based on adaptive gain. The wireless passive sensing system comprises a reading resonator and two sensing resonators. The read resonator includes a capacitor, an inductor, and a negative resistor. Each of the two sensing resonators comprises a capacitor, an inductor and a resistor. The natural frequencies of the two sensing resonators are kept symmetrically offset relative to the natural frequency of the reading resonator. By adding disturbance to any resistor in the two sensing resonators, a driving system is expanded to EP5, and the sensitivity in the sensing process is improved. Meanwhile, a vector network analyzer or an impedance analyzer is used as a negative resistor, and a zero crossing point of an input impedance imaginary part or a reflection coefficient imaginary part is used as an eigen frequency criterion in frequency scanning, so that a traditional'fixed gain-scattering extreme value 'is converted into a new measurement form of'impedance imaginary part zero crossing point-eigen frequency direct reading'.

This invention proposes a highly sensitive electromagnetic sensing device and method based on the singularity effect, belonging to the field of electromagnetic sensing technology. It includes: a first resonant unit, which is a lossy resonator; a second resonant unit, which is a resonator with added gain; and a coupling unit, which is a coupling capacitor placed between the first and second resonant units, forming a non-Hermitian coupled system. The system operates in a second-order singularity state under preset parameter conditions. When the measured medium is applied to the coupling unit, the equivalent coupling capacitance of the coupling unit changes, causing the singularity condition of the system to be disrupted, resulting in frequency splitting of the system's intrinsic frequencies. By detecting the frequency splitting characteristics, the change in the dielectric parameters of the measured medium is sensed. This invention significantly improves sensing sensitivity and resolution, and is suitable for applications such as biological detection, chemical analysis, and environmental monitoring in the microwave, millimeter-wave, and terahertz frequency bands.

The embodiment of the application discloses a frequency modulation external cavity laser device, which comprises a seed light source, a feedback loop external cavity, a light source frequency adjusting module, an FP cavity frequency adjusting module and an external cavity frequency adjusting module; the feedback loop external cavity comprises an FP cavity; the light source frequency adjusting module is used for adjusting the intrinsic frequency of the seed light beam; the FP cavity frequency adjusting module is used for adjusting the resonance frequency of the FP cavity; the external cavity frequency adjusting module is used for adjusting the resonance frequency of the feedback loop external cavity; the light source frequency adjusting module, the FP cavity frequency adjusting module and the external cavity frequency adjusting module are cooperatively modulated, so that the intrinsic frequency of the seed light beam, the resonance frequency of the FP cavity and the resonance frequency of the feedback loop external cavity satisfy the external cavity self-injection locking condition, and a frequency-locked laser is formed. The embodiment of the application solves the problem that the frequency modulation range of the existing narrow line width laser is small, can greatly improve the frequency modulation range, constructs a fast and wide range continuous frequency modulation external cavity narrow line width laser, and expands the application field of the laser device.

The application discloses a feedback oscillator structure applied to a traveling wave tube, which comprises waveguide structures, a resonant cavity frequency selection structure and a waveguide power regulation structure which are connected in sequence; the input end of the waveguide structure is connected with the output end of the traveling wave tube, the waveguide structure and the resonant cavity frequency selection structure are connected through a coupling gap, the resonant cavity frequency selection structure and the waveguide power regulation structure are connected through a coupling gap, and the output end of the waveguide power regulation structure is connected with the input end of the traveling wave tube; the frequency selection characteristic of the resonant cavity frequency selection structure is used to select the resonant cavity eigenfrequency part from the noise wave output from the output end of the traveling wave tube, the power is adjusted, and then the selected part is input to the input end of the traveling wave tube, so that the self-excited oscillation of the traveling wave tube with adjustable frequency is realized. The application does not need a solid-state oscillation source, in the terahertz frequency band, the feedback oscillator structure can realize the high-power output of the traveling wave tube without input signals, has the frequency modulation function, and the frequency spectrum of the output signal is relatively pure.

The invention discloses a self-adaptive vibration signal noise reduction and modal recovery method and system, and relates to the technical field of civil engineering monitoring and artificial intelligence fusion application, and the method comprises the following steps: constructing a multi-source vibration signal collection channel, and obtaining time sequence response data of a structure in a service state; performing normalization and sliding slice preprocessing on the original signal; an optimal noise reduction strategy is dynamically selected based on a preset noise level, and self-adaptive adjustment of signal enhancement and noise suppression is realized; restoring a dominant frequency structure of the signal in combination with a spectrum analysis technology, and extracting structural modal parameters such as an eigenfrequency, a damping ratio and a vibration mode feature; a joint optimization model of signal de-noising and modal maintenance is constructed through a modal constraint loss function, and it is ensured that modal information is not damaged in the de-noising process. According to the adaptive vibration signal noise reduction and modal recovery method and the adaptive vibration signal noise reduction and modal recovery system, high-fidelity recovery of structural vibration signals and accurate extraction of key modal characteristics in a strong interference environment are realized.

The application provides a mechanical loss measuring device, and relates to the technical field of material mechanics. The mechanical loss measuring device comprises a containing assembly, which forms a vacuum chamber; a clamping assembly, which is installed in the vacuum chamber and is used for clamping a first part of a test substrate, a second part of the test substrate extends from the clamping assembly, and the second part is formed with an optical film to be measured; and a driving assembly, which is suitable for driving the second part to vibrate. The natural frequency of the clamping assembly is greater than the natural frequency of the test substrate, so that resonance coupling between the clamping assembly and the test substrate is avoided. First incident laser passes through a light transmission part and is incident on the optical film to be measured. First reflected laser, which is obtained after the first incident laser is reflected by the optical film to be measured, carries vibration information of the optical film to be measured, and the first reflected laser is used for determining the mechanical loss of the optical film to be measured. The mechanical loss measuring device can stably excite the natural vibration of the test substrate at a low frequency of 100 Hz or below, and the measurement result of the mechanical loss has accuracy.

This invention relates to a method for identifying the rigid axis azimuth and frequency split of a hemispherical resonator based on orthogonal antinodes and phase shift variables. It belongs to the field of hemispherical resonator gyroscope parameter identification, specifically involving a method for identifying the rigid axis azimuth and frequency split of a hemispherical resonator. The purpose of this invention is to solve the problems of difficulty and inaccuracy in identifying frequency split and rigid axis azimuth during existing hemispherical resonator mass adjustment processes, leading to low gyroscope sensitivity and measurement accuracy. This invention significantly improves the testing efficiency of rigid axis azimuth and frequency split; the testing of rigid axis azimuth and frequency split is not limited by the quality factor; it is not affected by intrinsic frequency drift; it can directly distinguish the high and low frequency axes of the resonator, avoiding the possibility of incorrect leveling direction; the changes in orthogonal antinodes and phase shift are linearly time-dependent, increasing measurement reliability and convenience; and it improves the frequency split adjustment accuracy and efficiency of the hemispherical resonator.

A method for determining bearing preload by vibration measurement includes: mounting the bearing on a vibration tester; clamping the outer ring to prevent rotation; mounting a sensor near the outer ring to measure vibration; rotating the inner ring of the bearing to uncover the eigenfrequency; transmitting the measured vibration data from the sensor to a computer workstation; the computer workstation performing a numerical FFT that transforms the data to the frequency domain; analyzing the spectral data from the FFT by the computer workstation; a peak detection algorithm determining the peaks as the various modes of the outer ring; classifying the modes and identifying the dominant mode; obtaining a numerical relationship for each mode between resonance and preload; comparing the mode relationship with one or more benchmarks; a match between the numerical relationship of each mode and the numerical relationship of the ideal benchmark's graphical mode indicates that the correct preload has been determined. Additionally, a system for performing this method.

The present invention relates to a quantum cascade laser modulation bandwidth test system and method, wherein the test system comprises a detection quantum cascade laser, a first T-type bias device, a second T-type bias device, a radio frequency source and a spectrum analyzer; the sub-cascade laser to be measured is optically coupled with the detection quantum cascade laser, so that the eigenfrequency of the sub-cascade laser to be measured is mixed with the optical frequency comb frequency line of the detection quantum cascade laser to generate a beat frequency signal; the radio frequency source is used to generate a modulation signal, and the modulation frequency is adjusted with a preset frequency as the interval, so that the sub-cascade laser to be measured generates a modulation sideband; the spectrum analyzer is used to record the beat frequency signal of the modulation sideband and the optical frequency comb frequency line. The present invention can accurately characterize the modulation bandwidth of the quantum cascade laser.