26 results about "Phase cancellation" patented technology

The technology described herein is directed towards resonators that incorporate or are closely coupled to transducers from which energy is harvested. The resonators can be unit cells of a metasurface configured for narrowband sound absorption by phase cancellation of the acoustic wave Electroacoustic transducers such as piezoelectric transducers can be positioned, e.g., at the neck ports of the resonators, to generate electricity as the air pressure of incoming acoustic waves enters the unit cells. Energy can be harvested from the electricity, and stored for usage and / or used directly to power a device. Such a device powered by the harvested energy can change the resonant frequency of the device, e.g., by changing temperatures in the resonators' air cavities, changing respective dimensions of the respective air cavities, or changing the resonant frequency of the unit cells resonators by changing respective airflow in the respective air cavities.

The invention provides an extended target phase offset coherent waveform design and efficient accumulation method. The method comprises the following steps: acquiring a pulse signal of a JFPA waveform received by a target, returning echo signals of a plurality of extended targets, and searching a target coarse velocity by using a minimum envelope entropy, constructing a matching function to perform motion compensation on the echo signal to obtain a two-dimensional time domain signal; taking the jitter initial phase of the echo signal corresponding to the reference waveform as a matched filter, and compensating the jitter initial phase of the echo signal corresponding to the coherent accumulation waveform; and designing the echo signal after initial compensation as a coherent echo signal, and performing Fourier transform on the coherent echo signal along slow time to obtain a coherent accumulation result of the target. According to the method, accurate initial phase jitter compensation is completed without target distance information, the method is suitable for an extended target, and after the echo signal of the JFPA waveform is subjected to initial phase jitter compensation, the phase is controlled to be uniform, so that the complexity of FFT coherent processing can be reduced.

The application discloses a VHF frequency band adaptive filtering response method and system, and relates to the field of VHF frequency band signal processing.The application effectively solves the problems of signal interference and multipath effect in VHF frequency band communication through the adaptive filtering response method, and realizes accurate separation of reflected path signals and main path signals through time domain and frequency domain analysis, combination of a delay detection algorithm and an adaptive filtering algorithm.Further, the interference of the reflected path signals is eliminated through a phase cancellation mechanism, and the transmission quality of the signals is significantly improved.

The present invention discloses a frequency stepped signal radar imaging method based on phase cancellation to improve the high-resolution imaging effect of high-speed moving targets. The frequency stepped signal radar imaging method of the present invention includes the following steps: (10) Transmitting frequency stepped signals: Alternately transmitting two sets of frequency stepped signals, where the pulse repetition period of one set of frequency stepped signals is twice that of the other frequency stepped signal; (20) Obtaining echo signals: Obtaining echo data reflected by target scattering points; (30) Range image motion compensation: Using an improved phase cancellation algorithm to perform range image velocity phase compensation on the echo data; (40) Frequency stepped signal range imaging: Performing an inverse Fourier transform on the echo sampling sequence and then performing oversampling stitching to obtain a high-resolution stationary range image of the moving target.

The present invention discloses a novel microstrip antenna with a low radar cross section. This antenna is formed by etching periodic metal patterns with different structures on the microstrip feeder layer and the intermediate metal layer of the original microstrip coupled-fed antenna. Through partial overlap of the periodic metal patterns with different structures, while having the wave-transmitting characteristic outside the operating band of the antenna, it also has a broadband phase cancellation effect, realizing the reduction of the antenna RCS in the broadband range outside the band. Compared with the traditional low-RCS microstrip antenna based on a single wave-transmitting periodic structure, this antenna greatly improves the reduction effect of the radar cross section.

The application discloses a dynamic interference suppression method of multipath channel phase focusing and harmonic reverse phase cancellation, relates to the technical field of interference suppression, and comprises a path characteristic extraction module, which extracts sampling data of a received signal, constructs a received signal matrix, generates a pilot signal, carries out filter processing on a noise matrix, calculates a channel frequency response matrix, and extracts path characteristics by using a peak value detection method. The method can comprehensively calculate the time delay component contribution of the channel time domain response by discretizing the channel frequency response matrix through limited sampling points and combining all frequency components in the frequency bandwidth, can enhance the dynamic response capability of the channel model by introducing time-varying environmental characteristics through a dynamic path time delay function, can improve the signal characteristic correction precision through dynamic compensation of path time delay error phase rotation, and can realize the channel description process with path grouping as the core.

The technology described herein is directed towards resonators that incorporate or are closely coupled to transducers from which energy is harvested. The resonators can be unit cells of a metasurface configured for narrowband sound absorption by phase cancellation of the acoustic wave. Membrane-based transducers such as cymbal harvester transducers can be positioned, e.g., at the neck ports of the resonators, to generate electricity as the air pressure of incoming acoustic waves enters the unit cells. Energy can be harvested from the electricity, and stored for usage and / or used directly to power a device. Such a device powered by the harvested energy can change the resonant frequency of the device, e.g., by changing temperatures in the resonators' air cavities, changing respective dimensions of the respective air cavities, or changing the resonant frequency of the unit cells resonators by changing respective airflow in the respective air cavities.

The invention discloses a method and system for improving second and third harmonic indexes of an output port, and belongs to the technical field of electromagnetic fields and microwaves, and the method comprises the steps: S1, amplifying an input first excitation signal through a small signal amplifier, then extracting second and third harmonic signals, and outputting a second excitation signal; s2, preprocessing the output second harmonic signal and the output third harmonic signal; s3, performing broadband synthesis on the preprocessed second harmonic signal and the preprocessed third harmonic signal to output a dual-tone signal; s4, pre-processing the second excitation signal, outputting the pre-processed second excitation signal, and feeding the broadband synthesized dual-tone signal into the pre-processed second excitation signal; and S5, performing 180-degree phase offset on the second and third harmonics of the preprocessed second excitation signal through the dual-tone signal to obtain a third excitation signal, and outputting the third excitation signal to the antenna. Compared with a traditional method of adding filters, the method has the advantages that the transmitting power signal is increased by 0.4 dB; meanwhile, the efficiency index of the transmitter is improved, and the efficiency and reliability of the transmitter are improved.

This invention relates to the field of predictive maintenance technology and discloses a method for predicting the life of flange seals based on digital twins. The method includes: first, acquiring initial parameters to establish an initial reference acoustic energy density; then, acquiring real-time data to calculate the real-time raw acoustic energy density. Phase cancellation is performed based on the node spatial distance and real-time sound velocity to eliminate interference energy and obtain the decoupled true acoustic energy density. The decoupled density is compared with the reference density and substituted into an exponential model to calculate the microcavitation degradation factor. The degradation factor and real-time temperature are used to modulate the fluid density, thereby obtaining the fluid equivalent wave velocity, and combining this with pressure variables to calculate the asynchronous warping phase difference. The real-time residual clamping stress is obtained by reducing the preload stress based on the cosine value of this phase difference and the acoustic energy attenuation ratio. Finally, the transient fatigue damage evolution rate is calculated based on the residual stress and operating time to estimate the remaining life.

A first radio frequency filter and a second radio frequency filter disposed on a die, a first loop circuit disposed on the die, coupled to the first radio frequency filter, configured to generate a first anti-phase signal at a first frequency, and including a first signal line including a first reflector grating disposed between first interdigital transducer electrodes included in a first surface acoustic wave resonator of the first radio frequency filter and second of interdigital transducer electrodes included in a second surface acoustic wave resonator of the second radio frequency filter, and a second loop circuit disposed on the die, coupled to the second radio frequency filter, configured to generate a second anti-phase signal at a second frequency, and including a second signal line including a second reflector grating disposed between the first interdigital transducer electrodes and the second interdigital transducer electrodes.

The invention discloses an ultra-high-speed target imaging method and system based on double-step frequency phase cancellation. According to the method, the characteristic that two groups of stepping frequency signals with different repetition periods can be converted to a frequency domain on a slow time axis is utilized, and the stepping frequency signals are combined with a phase cancellation operator constructed by the frequency domain, so that a primary phase term and a secondary phase term caused by motion can be eliminated on the premise of keeping system parameters consistent; meanwhile, sampling envelope walking under the high-speed condition can be effectively restrained, so that stable correction is still achieved under the high-speed scene, the energy focusing capacity is improved, and the high-performance imaging method based on the frequency domain phase cancellation technology is obtained. According to the method, range image offset, image waveform divergence and sampling envelope walking can be effectively inhibited under the condition of ultra-high-speed motion, the speed application range of double-pulse-group stepping frequency imaging is expanded, and the target imaging focusing performance and the positioning precision are improved.

The present invention discloses an ultra-thin, broadband coded RCS reduction metasurface, which relates to the technical field of artificial electromagnetic metamaterials. The metasurface is composed of two metasurface units with the same reflection amplitude and a reflection phase difference of 180°, arranged according to an optimization rule obtained by a Particle Swarm Optimization (PSO) algorithm. Based on array theory, the present invention considers the design of two AMC structures for compounding, thereby effectively widening the RCS reduction bandwidth. Based on the principle of phase cancellation, and using a particle swarm optimization (PSO) algorithm, an ultra-thin, ultra-broadband coded RCS reduction metasurface is optimized and designed. The phase difference between the two metasurface basic units reaches 180°±1° over the full effective bandwidth (21-35GHz), resulting in the coded electromagnetic metasurface achieving excellent performance with a relative bandwidth of 47.2% and a reduction effect exceeding 10dB.

A kind of wideband low scattering microstrip array antenna based on phase cancellation mechanism, the array antenna is formed by the chessboard arrangement of extended Jerusalem cross microstrip antenna unit and bent Jerusalem cross microstrip antenna unit with similar radiation characteristics and approximately 180° reflection phase difference in wide frequency band range;Two kinds of microstrip antenna unit are composed of metal radiation patch, L-shaped coupling feed structure, metal floor and dielectric substrate. Among them, the L-shaped coupling feed structure is composed of rectangular feed patch and metallized via, which can control the two kinds of microstrip antennas to have similar radiation characteristics. The present application can maintain the normal radiation performance of microstrip array antenna and realize the wideband low scattering characteristics without introducing additional low scattering design structure, which can meet the design and application requirements of wideband stealth antenna system.

An antenna array controller is configured to measure a magnitude and phase of each of a set of antenna array elements, and compensate for leakage of other elements of the set of array elements. The leakage may be compensated for by one or more mechanisms including phase cancellation by row of antenna array elements, programmatic cancellation via a single offsetting antenna array element of the antenna array elements, and deembedding array leakage by subtracting the array leakage from the measured data.

The invention discloses a radio-frequency signal stable-phase transmission method, which comprises the following steps: S1, after a signal to be transmitted is transmitted into a power divider, one path of signal enters a phase adjustment unit to obtain a signal, and the other path of signal enters a digital phase comparison unit and is subjected to phase comparison with a signal before transmission; s2, the signal is divided into two paths of signals after being transmitted into a power divider, one path of signal is transmitted to a receiving end through a signal transmission link, and the other path of signal is returned to a transmitting end through an original optical fiber link; s3, inputting the signal returned to the transmitting end into a digital phase comparison unit for phase comparison with the signal to obtain phase fluctuations introduced by the signal through an optical fiber link twice; and S4, calculating the phase delay of the optical fiber link according to the digital phase comparison unit, assigning the phase adjustment quantity by the phase adjustment unit, and carrying out phase offset. Through back-and-forth detection of the noise of the optical fiber link and phase compensation before the signal passes through the optical fiber link, phase delay introduced in the subsequent transmission process is offset, and stable signal transmission is realized.

The invention discloses a dynamic interference suppression method for multipath channel phase focusing and harmonic inverse offset, which relates to the technical field of interference suppression, and comprises a path characteristic extraction module for extracting sampling data of a received signal, constructing a received signal matrix, generating a pilot signal, filtering a noise matrix and calculating a channel frequency response matrix, path characteristics are extracted using a peak detection method. According to the method, a channel frequency response matrix is discretized through limited sampling points, time delay component contribution of channel time domain response can be comprehensively calculated in combination with all frequency components in a frequency bandwidth, time-varying environment characteristics are introduced through a dynamic path time delay function, the dynamic response capability of a channel model is enhanced, and the dynamic response capability of the channel model is improved. The signal characteristic correction precision is improved through dynamic compensation of path time delay error phase rotation, and path grouping is used as a core channel description process.

A GIS basin type insulator ultrasonic flaw detection risk quantification method, device and storage medium belong to the technical field of power equipment detection, solve how to improve the precision of insulator defect ultrasonic flaw detection; the present application optimizes the parameters of multi-element linear array and dynamic focusing rule; the phase compensation superposition of multi-position echo signal is carried out by using synthetic aperture focusing technology, combined with phase cancellation and space-time filtering to suppress interference; the convolutional neural network is constructed to realize hierarchical extraction of defect features, the global features of defects are captured by sine position coding and multi-head self-attention mechanism through the use of transformer, and the feature fusion is completed through the use of feedforward neural network; the defect profile is extracted based on the dynamic threshold segmentation of Otsu method, and the size, depth measurement and risk grade evaluation are realized through pixel quantization and echo time calculation; it is suitable for high-precision detection of hidden defects in insulators, and realizes the intelligentization of the whole process from detection, feature extraction to risk quantification of insulator defects.

The invention discloses a single-beam depth sounder phase offset measurement method for suppressing aftershock aliasing of transducers, and relates to the technical field of underwater measurement, when a sonar transducer in a single-beam sonar depth sounder emits sound waves, the sonar transducer automatically switches to an aftershock monitoring mode, key characteristics of aftershock signals of the sonar transducer are extracted, and the aftershock signals of the sonar transducer are extracted; the method comprises the steps of receiving a sound wave echo signal, generating a phase offset signal, loading the phase offset signal on a sonar transducer to generate destructive interference with an aftershock signal of the sonar transducer, controlling mode switching of the sonar transducer according to propagation of the sound wave echo signal, receiving the echo signal reflected from the water bottom, and calculating the water depth. The self-adaptive capability of the sonar depth finder is enhanced, the accuracy of water depth measurement is guaranteed, and the continuity and consistency of measured data are also guaranteed.

A multi-layer piezoelectric substrate surface acoustic wave device is disclosed. The surface acoustic wave device can include a multi-layer piezoelectric substrate including a support substrate and a piezoelectric layer, a filter circuit including a plurality of resonators in electrical communication with the piezoelectric layer, a phase cancelling circuit integrated with the filter circuit, and an acoustic obstruction structure in the acoustic track of the phase cancelling circuit. An acoustic track of the phase cancelling circuit is offset from the plurality of resonators.

The invention discloses an ultra-wideband low-radar cross section circularly polarized antenna based on a hybrid mechanism, and the antenna comprises a radiation unit which is used for radiating circularly polarized electromagnetic waves; the in-band reduction layer is arranged on the radiation unit and is used for reducing a radar cross section in a working frequency band of the antenna through a phase cancellation mechanism; the out-of-band reduction layer is arranged on the in-band reduction layer and is used for reducing the radar scattering cross section outside the working frequency band of the antenna through a wave absorbing and transmitting mechanism; wherein the out-of-band reduction layer comprises adjacent metasurface units with different heights, and the out-of-band reduction layer is used for expanding the radar cross section reduction bandwidth of a high frequency band. By loading the unequal-height absorption and transmission integrated metasurface and the polarization conversion metasurface, wider RCS reduction bandwidth is realized.

The utility model relates to the technical field of acoustic devices, in particular to an XY loudspeaker replay structure, which is characterized in that two loudspeakers are respectively arranged on two axes which are perpendicular to each other, and vibrating diaphragms of the two loudspeakers are partially overlapped in a Z-axis direction, so that the two loudspeakers emit same sound channel signals, and phase offset caused by phase difference is avoided. The utility model has the advantages that: the elimination of phase offset is realized; and when the two loudspeakers play the same signal and no time delay exists, the phase offset phenomenon possibly occurring in the traditional multi-loudspeaker system is effectively prevented. And the sound energy radiation range is obviously expanded: the superimposed effect of the signals of the two loudspeakers can create an ultra-wide directional coverage area which can generally reach 180 degrees, so that the sound energy radiation range is obviously expanded. The sound coverage effect is enhanced: through the specific loudspeaker layout, the sound is covered more widely, a more uniform sound field effect is provided, and the loudspeaker is suitable for occasions requiring wide sound coverage.

The application discloses a method and system for improving output port second and third harmonic indexes, and belongs to the field of electromagnetic field and microwave technology.The method comprises the following steps: S1, amplifying an input first excitation signal through a small signal amplifier, then extracting second and third harmonic signals, and outputting a second excitation signal; S2, pre-processing the output second and third harmonic signals; S3, outputting a wideband synthesized double-tone signal by the pre-processed second and third harmonic signals; S4, outputting the pre-processed second excitation signal after pre-processing, and feeding the wideband synthesized double-tone signal into the second excitation signal; S5, obtaining a third excitation signal by 180-degree phase cancellation of the second and third harmonics of the pre-processed second excitation signal through the double-tone signal, and outputting the third excitation signal to an antenna.Compared with the traditional method of increasing filters, the transmission power signal is increased by 0.4 dB; meanwhile, the efficiency index of the transmitter is improved, and the efficiency and reliability of the transmitter are improved.

The application discloses a phase elimination method and system of a 90-degree optical frequency mixer, and the phase elimination method comprises the following steps: S1: determining an additional phase introduced by a cross waveguide of the 90-degree optical frequency mixer for an optical channel; and S2: eliminating the additional phase introduced by the cross waveguide by a phase elimination method. The application eliminates the phase by the phase elimination method of the 90-degree optical frequency mixer, avoids the introduction of the additional cross waveguide, reduces the overall optical power loss of the 90-degree optical frequency mixer, and further improves the performance of the 90-degree optical frequency mixer.

The invention relates to a radiation integrated low RCS antenna with high angle stability and a design method thereof, and belongs to the technical field of electromagnetic stealth. The problems that a traditional antenna RCS reduction technology is prone to deteriorate radiation performance, the bandwidth is narrow, and oblique incidence is unstable are solved. According to the technical scheme, a three-layer structure is adopted, an artificial surface plasmon polariton metasurface achieves RCS reduction through wave absorption, a metasurface array achieves RCS reduction through phase cancellation, and a feed network feeds through slot coupling; the design method comprises the steps of RCS reduction frequency band determination, metasurface unit design, feed network matching and the like. The technical effects are that the ultra-wideband RCS is reduced, the angle stability is high, the good radiation performance is maintained, the structure is simple, the work is stable, and the like.

This invention relates to a broadband angular domain RCS reduction structure based on the synergy of wave absorption and phase cancellation, belonging to the field of electromagnetic functional materials and structures. It is composed of several periodically distributed metamaterial units. Each metamaterial unit has a matching layer, an upper substrate layer, a copper pattern layer, a lower substrate layer, and an absorbing medium layer distributed sequentially from the incident wave irradiation direction. The copper pattern layer includes an octagonal frame cut around the perimeter and a cross structure located in the center of the octagonal frame. The octagonal frame and cross structure are of different sizes among the various metamaterial units. This invention has the advantages of breaking through the working bandwidth limitation of a single mechanism and significantly improving azimuth adaptability, providing a new solution for broadband large-angle stealth technology.