51 results about "Coherent wave" patented technology

The invention discloses a single-snapshot data-based coherent signal DOA estimating method and relates to the technical field of array antenna systems or methods capable of indicating different signal directions. The method comprises rearranging the single-snapshot received data of an array to obtain two pseudo-covariance matrixes, and then through two pseudo-covariance matrixes, expanding the covariance matrix of a subspace restructuring algorithm; performing singular value decomposition on the new pseudo-covariance matrixes to obtain a signal subspace and a noise subspace, and performing DOA estimation on incoming coherent wave signals through a MUSIC spectrum estimating method. The single-snapshot data-based coherent signal DOA estimating method can eliminate coherence among source signals under single-snapshot conditions and meanwhile further improve the DOA estimating precision. The single-snapshot data-based coherent signal DOA estimating method is mainly applied to rapid estimation of incoming directions of coherent signals under the single-snapshot conditions.

Coherent wave noise energy is removed from seismic data by modeling both the P-wave primary energy and the coherent wave noise energy. The P-wave primary energy is modeled first and then subtracted from the input data. The data with the P-wave primary energy removed is used as the input for coherent wave energy removal. The coherent wave energy is modeled and subtracted from the original input data, i.e. the data input into P-wave primary removal. This leaves a dataset with P-wave primary energy and noise energy not related to coherent waves. This method can be utilized to remove all types of coherent noise with a velocity difference to the desired P-wave primary energy or with a different type of moveout (change of time of arrival with source-receiver distance) such as, for example, linear moveout.

The invention provides a life form detection processing method and apparatus, and a terminal. The method comprises the following steps: emitting WiFi electromagnetic waves; receiving coherent waves of reflection waves of the WiFi electromagnetic waves and the WiFi electromagnetic waves; and according to the received coherent waves, determining life form information. According to the invention, the problems of inconvenient user operation, low popularization rate and low versatility existing in life form detection in related arts are solved, and the effects of high portability, easy use and timely use are achieved.

A system and method for providing coherent sources for phased arrays are provided. One method includes providing a plurality of transceivers configured to transmit signals and defining an array of nodes. The method also includes providing a plurality of beacons at different frequencies to one of aim or focus phase coherent energy generated by the transmitted signals from the plurality of transceivers, wherein the phase coherent energy is transmitted at a direction and a frequency determined with phase conjugation and independent of the location of the plurality of beacons.

Disclosed is a method for producing a surface structure which is antireflective for a wavelength range with a minimal wavelength lambdaM, having a supporting coat on which a light-sensitive material is applied which is exposed with at least two mutually coherent wave fields with a wavelength of lambdaB in order to obtain a stochastically distributed interference field, whereby during or after exposure, said surface structure is formed by means of selective removal of materials. The invention is distinguished by mutually interfering, coherent wave fields directed at the light-sensitive coat of material forming an angle alpha, for which applies: alpha>2 arcsin(lambdaB/(2.lambdaM))

The invention belongs to the field of electromagnetic wave and novel artificial electromagnetic materials and particularly relates to a dynamically tunable broadband polarization converter, comprising a dielectric layer and a novel artificial electromagnetic material layer. The novel artificial electromagnetic material layer is located on the surface of the dielectric layer, wherein novel artificial electromagnetic material is square diagonal split rings arranged periodically, and the novel artificial electromagnetic material is of sub-wavelength structure; dynamical tunability is based on the principle of coherent control and is finished through two coherent waves, namely a signal wave and a control wave, the two waves have the same amplitude and wavelength and propagate face to face in a direction perpendicular to the novel artificial electromagnetic material, and a phase difference between the signal wave and the control wave is changed. The converter has the advantages of portability, light weight, ease of integration and the like and is of single layer, small thickness, light weight and conformal proneness when compared with a traditional polarization conversion material.

A coherent radiation imaging system that produces digital images with a reduced amount of speckle. Radiation from a long coherence length source is used to form an image of a sample. The output coherent wave is temporally divided into a plurality of wavelets. The spatial phase of each wavelet is then modulated a known and different amount. Each phase modulated wavelet illuminates the sample and is perturbed by its interaction with the sample. A spatial phase map of each perturbed wavelet is then created and converted to a sample image with an image reconstruction program. The plurality of sample images thus formed is statistically averaged to form a final averaged image. The high frequency speckle that is not optically resolvable tends to average to zero with continual statistical averaging, leaving only the optically resolvable lower frequency phase information.

The invention is a phase unwrapping method to process coherent waves. The feature is: first to do vector filter on the phases containing remnant pixel, then to unwrap phases with reliability phase unwrapping method. The mentioned vector filter is to compute sine and cosine value of each pixel in the phase, and perform the average filtering on the continuous sine and cosine images, finally obtain the phase value of filtered interference image by inverse mapping; then wrap the phases with reliability phase unwrapping method: first construct the reliability, then wrap the phases in order according to the value of reliability.

The invention discloses a PWM (pulse-width modulation) module which is applied to a flyback type switching power supply topology, can cause reverse voltage of D-S two ends of the topology to be lower and can always alternatively generate an interruption mode and a critical mode. The PWM module comprises a PWM control circuit and a sawtooth generator, and further comprises a zero current detection and start synchronizing circuit and a load weight sawtooth wave frequency conversion circuit, wherein the PWM control circuit is used for switching off fixed clock start peak current; the zero current detection and start synchronizing circuit can generate phase coherent waves; after the coherent waves and sawtooth waves are iterated, the PWM control circuit can start another alternative PWM signal output; and when a flyback circuit works in a current continuous mode, the sawtooth waves work under different frequencies by the load weight sawtooth wave frequency conversion circuit. According to the PWM module disclosed by the invention, the flyback circuit always works in a current interruption mode and critical mode alternatively generating state; the reverse voltage generated by the D-S two ends of a switching tube is reduced to 1.2-1.5 times of power source voltage; and the PWM module has a simple structure, the controlled flyback topology switching on-off loss is small, the service life is long and a few of ultraharmonics are generated.

The invention provides a denoising method and device for a brake system. The denoising method for the brake system comprises steps as follows: acquiring noise signals; screening the noise signals, and obtaining a low-frequency brake noise signal; analyzing the low-frequency brake noise signal, and generating a denoising signal coherent with the low-frequency brake noise signal according to coherent wave coherent conditions; playing the denoising signal. According to the technical scheme, an active denoising technology is adopted, low-frequency brake noise can be effectively reduced in the principle of sound wave interference, and the noise optimizing period is short.

The invention relates to a maritime radio communication monitoring and direction finding system which is characterized by comprising a vertical polarization monitoring and direction finding antenna array, a five-channel signal switching module, an amplification module, a five-channel receiver, a digital signal processor (DSP) processing module, a computer, a monitoring and direction finding controller, a 3rd generation (3G) antenna, a radio station antenna, a 3G router, a digital broadcasting station, a switchboard, an electronic compass, a global positioning system (GSP) module and a GSP antenna. The maritime radio communication monitoring and direction finding system has the advantages that: an interfering signal can be monitored better due to the working frequencies ranging from 30 to 500MHz; simultaneous direction finding of several coherent waves is realized; simultaneous direction finding and ultrahigh-resolution digital direction finding of transmitting signals with same frequency and different directions are realized; direction finding of digital frequency hopping, a spread spectrum and a burst signal is realized; monitoring and measuring on different frequency domains, different time domains and different modulation domains can be simultaneously performed during measuring due to respective local oscillation of five channels; the problem of cross coupling among all antenna array elements is solved; the coupling and the phase ambiguity among unit antennas are removed; and dynamic application ranges of received signals are expanded.

An adaptive optics system comprises a beamsplitter configured to divide an incoming beam with an aberrated wave front into a first input beam and a second input beam, a microelectromechanical system configured to reflect the first input beam onto an image plane, and a self-reference wave front generator configured to spatially filter the second input beam to form a reference beam, and to interfere the reference beam with the first input beam on the image plane to form a hologram. The system further comprises an imaging device configured to capture an image of the hologram on the image plane, and one or more processors. The one or more processors are configured to perform the steps of Fourier transforming the captured image to generate a transform including a first object image, a conjugate object image, and an auto-correlation image, truncating the transform to exclude the conjugate object image and the auto-correlation image, inverse Fourier transforming the truncated transform to generate amplitude and phase information about the aberrated wave front, generating control signals for mitigating aberrations in the aberrated wave front via phase conjugation based on the amplitude and phase information, and providing the control signals to the microelectromechanical system.

The present invention employs one or two radiation arrays to motivate a higher-mode TEn0 mode (n is an integer larger than or equal to 2) as much as possible at the front portion, the rear portion orthe upper portion of a heating cavity of a transversely uniform microwave oven so as to form standing waves in the heating cavity. The at least one radiation array comprises at least two lines of radiators in a Z direction. The at least one radiation array radiates the microwave energy to the heating cavity through a floor. The radiators on any one radiation array are uniformly distributed in theX direction and the Z direction. The radiated microwaves in all the radiators on the same radiation array are coherent waves. In order to further improve the heating uniformity, a rotary table with transverse translation or processing around a vertical axis of the heating cavity is employed. The microwave mode in the cavity of the transversely uniform microwave oven is controlled to improve the heating uniformity of the transversely uniform microwave oven in the three-dimensional space.

A phase-shift holographic device based on a phase-type vortex lens and an imaging method are disclosed. The device comprises a light source, a beam splitter, a rotating lens frame, a phase-type vortexfocusing lens, a collimating lens, a first reflecting mirror, a beam combiner, a first three-dimensional translation stage, an imaging detector, a computer, a second reflecting mirror, a second three-dimensional translation stage and a measured object. The phase-type vortex focusing lens used in the invention can be used for a coherent wave band from visible light to a Terahertz wave band. In theinvention, the space-bandwidth product of the imaging detector can be fully used, the accurate reproduction of the measured object can be rapidly realized, the conjugate image of a reproduction result can be effectively restrained, and the reproductive image quality of the measured object can be obviously increased.

The invention discloses a broadband high-sensitivity millimeter wave receiving system based on carrier suppression, which is characterized in that a dual-wavelength generation structure based on carrier suppression comprises that a single-tone signal generated by a microwave source directly drives an intensity modulator, and the intensity modulator works at a carrier suppression point to generate two coherent wave beams; a microwave photon down-conversion structure based on the intensity modulator comprises the following steps: modulating a radio frequency carrier signal to a beam of light wave in a carrier suppression dual-wavelength generation structure by using the intensity modulator, and keeping a-1-order sideband by using fiber bragg grating filtering; and a homodyne coherent detection unit which is used for performing homodyne coherent detection by using the other light wave beam generated by the carrier suppression dual-wavelength generation structure and a-1-order sideband output by the microwave photon down-conversion, so as to realize photoelectric conversion and complete demodulation from the millimeter wave radio frequency signal to the baseband signal. According to the invention, down-conversion of any millimeter wave radio frequency signal is realized, large-capacity and long-distance transmission of millimeter wave wireless communication is supported, the principle is simple, and the application value is high.

The invention discloses a ship attitude motion component removal method based on spatial displacement. The method comprises the following steps of: establishing an expression of comprehensive Dopplerfrequency shift measured by a shipborne coherent radar; calculating six-degree-of-freedom ship motion amplitude response factors on the basis of sea wave frequency component distribution characteristics according to the style data of a ship body under the condition that the ship body is excited by waves of a unit wave height; based on a sea wave frequency spectrum measured by the radar at the lastmoment, obtaining the fluctuation rule of a ship by constructing a wave surface equation of a regular sea surface, and then obtaining the sea surface wave height displacement of the position of the ship body; performing six-degree-of-freedom coordinate conversion under an earth coordinate system and a ship coordinate system; calculating the spatial displacement of a radar antenna in a time periodaccording to the space coordinate difference between a previous moment and a next moment; finally solving the additional Doppler frequency shift caused by the attitude motion component of the ship body, and removing the component from the radar echo Doppler frequency shift. The method can effectively improve the extraction effect of the radial velocity of real water quality points of sea waves, and improves the precision of coherent wave-measuring radar sea wave parameter inversion.