370 results about "Phase variance" patented technology

The object of the present invention is to provide an apparatus capable of X-ray imaging utilizing phase of X-rays with a simple construction. The X-ray imaging apparatus of the present invention is equipped with first and second diffraction gratings and an X-ray image detector. The first diffraction grating is constructed to generate the Talbot effect using X-rays irradiated at the first diffraction grating. The second diffraction grating is configured so as to diffract the X-rays diffracted by the first diffraction grating. The X-ray image detector is configured so as to detect the X-rays diffracted by the second diffraction grating. By diffracting X-rays diffracted by the first diffraction grating, the second diffraction grating is capable of forming image contrast caused by changes in phase of X-rays due to the subject arranged in front of the front surface of the first diffraction grating or between the first diffraction grating and the second diffraction grating. The X-ray image detector is capable of detecting X-rays creating image contrast.

An automatic sampling control system for digital monitors. A clock generation circuit generates a sampling clock. A phase controller modifies the phase of the sampling clock by a phase amount. An ADC samples a frame of an analog display signal to generate digital samples. A value which is a function of the samples is generated. The function generally generates a larger value with correspondingly large sample values. The phase amount is modified for successive image frames until a maximum function value is generated. When successive image frames do not change substantially in image content, the phase amount represents the optimal phase change for the sampling clock. If the image content is changing substantially, the phase adjustment may be disabled.

High power optical pulses generating methods and laser oscillators are provided. A light generating module generates seed optical pulses having predetermined optical characteristics. A spectrum tailoring module is then used to tailor the spectral profile of the optical pulses. The spectral tailoring module includes a phase modulator which imposes a time-dependent phase variation on the optical pulses. The activation of the phase modulator is synchronized with the passage of the optical pulse therethough, thereby efficiently reducing the RF power necessary to operate the device.

A method for a short-term prediction of future ship motion in open water to furnish visual cueing information that can be remotely presented to a pilot during an aircraft landing is described. Two sets of samples of the sea surface geometry along a radial azimuth line from a ship as a function of elevation of a sensor are first acquired. These are compensated to remove the components due to the ship's motion. Two wave traces are then separately derived in Cartesian format from the two sets of acquired samples. These wave traces are subjected to a Fast Fourier Transform to detect the amplitudes and phases of the individual wavelength components. The direction of the wavelength components is determined using a measure of their phase change in the scan direction during the time interval between the two scans together with their measured wavelength. The amplitude, direction and phase of each component is utilized together with the known motion characteristics of the moving ship in order to derive a short-term prediction of future ship motion in the time domain. A quiescent period of the ship motion is located by comparing the short-term prediction with the pre-defined operating limit criteria. Finally, a message signal is transmitted to the pilot of the aircraft indicating Time-to-Land and the duration of the quiescent period.

Variations in spatial phase distribution due to static magnetic field changes are corrected based on phase variations at points, specifically, at three points or a plurality of points selected by ROI, in an area where no temperature change is encountered. And a temperature distribution image is determined by using a spatial phase distribution reflecting only temperature changes after the correction, thereby high-accuracy temperature distribution image information is provided.

A method and apparatus for reading a microbead having a code thereon is provided wherein the code is projected on and read from a Fourier plane. The microbead may be 1-1000 microns (um) or smaller in feature size. The code is projected on the Fourier plane by scattering input light off the microbead. The scattered light from the microbead is directed through an optical arrangement having a transform lens for projecting the code on the Fourier plane, and read on the Fourier plane using a charge coupled device (CCD) or other similar device. The code may include periodic layers of material having different refractivities or phase, including index of refraction differences; periodic spatial modulations having a different phase or amplitude; a periodic binary phase change used to code information in the Fourier plane; a photonic crystal used to encode the information on the microbead, wherein a pattern of holes causes interference between incident and scattered light to form spatial and spectral patterns in the far field that are unique to the pattern of holes; or may be formed in the microbead using a single photoactive inner region, a series of longitudinal holes, different fluorescence regions, or concentric rings of material in a preform.

The methods described herein are methods to ascertain motion contrast within optical coherence tomography data based upon phase variance. The phase variance contrast observes the nanometer scale motion of scatterers associated with Brownian motion and other non-flow motion. The inventive method of calculating motion contrast from the phase variance can differentiate regions of different mobility based on the motion contrast differences, and can use the phase information to characterize mobility properties of the scatterers. In flow regions, the inventive method for acquiring and analyzing motion contrast can identify the regions as well as characterize the motion. Furthermore, the inventive method can determine quantitative flow estimation, the index of refraction variations, and absorption variations within flow regions.

A system and method for using terahertz radiation to detect and monitor a substance undergoing a change in phase from a liquid phase to a solid phase or vice-versa is disclosed. By employing terahertz radiation in either the pulsed mode or in the continuous-wave (CW) mode, the system can non-invasively monitor these changes. The system uses the principle that matter in a liquid state will absorb and attenuate terahertz radiation to a larger degree than matter in a semisolid or solid state. Most terahertz radiation absorption occurs due to the rotational motions of molecules, i.e. either whole molecules or groups of atoms rotating about molecular bonds.

A power combining array and method of increasing performance in a power combining array includes a waveguide enclosure having a plurality of slotline modules disposed therein. The slotline modules include input and output antennas that have varying physical characteristics to overcome differences in field intensity across the slotline module configuration and to account for phase changes. The varying physical characteristics include differences in longitudinal position, thickness, dielectric constant, and circuit element configurations. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

An optical time domain reflectometry apparatus has a laser and light modulator for producing coherent light pulses, each having two sections of higher intensity separated by a gap of lower or substantially zero intensity. As the light pulses propagate along the optical fibre, light is continuously Rayleigh backscattered by inhomogeneities of the optical fibre. A photodetector generates backscatter signals representing the intensity of light Rayleigh backscattered in the optical fibre as each light pulse travels along the optical fibre. The PC uses these backscatter signals to derive a difference signal representing a change dI in intensity between signals generated from two successive pulses. The PC then calculates the Root Mean Square (RMS) of the difference signal averaged over the interval between the two sections of the light pulses. Next, the PC averages the backscatter signal generated from the first of the pulses over the same interval and normalises the RMS difference signal using the averaged signal to obtain a compensated difference signal that depends only on differences in the rate of change of phase of light of the light pulses as they travelled along the waveguide. This is repeated at different wavelengths to allow the compensated difference signal to be adjusted to represent the magnitude of the differences.

A method and apparatus for identifying a sample, involves illuminating the sample with light of varying wavelengths, transmitting an acoustic signal against the sample from one portion and receiving a resulting acoustic signal on another portion, detecting a change of phase in the acoustic signal corresponding to the light of varying wavelengths, and analyzing the change of phase in the acoustic signal for the varying wavelengths of illumination to identify the sample. The apparatus has a controlled source for illuminating the sample with light of varying wavelengths, a transmitter for transmitting an acoustic wave, a receiver for receiving the acoustic wave and converting the acoustic wave to an electronic signal, and an electronic circuit for detecting a change of phase in the acoustic wave corresponding to respective ones of the varying wavelengths and outputting the change of phase for the varying wavelengths to allow identification of the sample. The method and apparatus can be used to detect chemical composition or visual features. A transmission mode and a reflection mode of operation are disclosed. The method and apparatus can be applied at nanoscale to detect molecules in a biological sample.

An optical frequency comb calibration-based dual-color laser scanning absolute distance measuring device and a method are characterized in that the device comprises a laser light source system, a polarization-maintaining optical fiber system, a Michelson interference system and a laser frequency calibration system. The method comprises the steps of controlling two tunable lasers in the laser light source system to continuously simultaneously adjust the output light frequency without mode skips, wherein the laser frequency calibration system records the interference signal of the Michelson interference system and a beat frequency signal of the tunable lasers and the optical frequency comb; computing the scanning range of the lasers and the period integer and period decimal of the phase change of the interference signal in the scanning process according to the collected data; and finally computing to obtain the absolute distance of a to-be-measured light path refractive face. The optical frequency comb calibration-based dual-color laser scanning absolute distance measuring device and the method have the advantages of simple system structure, high measuring precision, compensating effect on air refractive index, and traceable measuring outcome, and are suitable for the measuring field of space absolute distance.

A path detector (140) detects a plurality of multi-path waves that have satisfied a predetermined standard from reverse spread signals, a plurality of adders (161) form beams on the basis of a path, a plurality of transfer path estimating sections (170) and complex conjugate calculators (163) calculate a transfer path estimation value, and based upon the result of the estimation, carry out a weighting process in accordance with the signal amplitude and a removing process of the phase variations. Moreover, a plurality of interference amount estimating sections (171) extract the amount of interference, a plurality of normalizing sections (172) normalize the signals that have been subjected to the phase variation removing process based upon the amount of interference, an adder (185) combines all the signals that have been normalized, and a data determining section (190) determines the signal that have been combined.

A novel method and apparatus for improving transmit antenna weight tracking using channel vector element to element correlations in a wireless communication system is disclosed. The present channel autocorrelation tracking technique utilizes the observation that tracking can be improved when a channel gain vector contains correlated elements. In a first embodiment of the autocorrelation tracking technique, the present invention extracts a coarse gradient estimate by utilizing a perturbation vector autocorrelation matrix estimate and a perturbation autocorrelation matrix to update TxAA weight vectors accordingly. In a second embodiment of the channel autocorrelation tracking technique, the present invention extracts a coarse gradient estimate by utilizing eigendecompositions, perturbation vector autocorrelation matrix estimates, and perturbation autocorrelation matrices to update TxAA weight vectors accordingly. In a third embodiment of the channel autocorrelation tracking technique, the present invention reduces the phase change that can occur at receivers.

The present invention integrates the surface plasmon resonance and common-path phase-shift interferometry techniques to develop a microscope for measuring the two-dimensional spatial phase variation caused by biomolecular interactions on a sensing chip without the need for additional labeling. The common-path phase-shift interferometry technique has the advantage of long-term stability, even when subjected to external disturbances. Hence, the developed microscope meets the requirements of the real-time kinetic studies involved in biomolecular interaction analysis. The surface plasmon resonance microscope of the present invention using common-path phase-shift interferometry demonstrates a detection limit of 2×10−7 refractive index change, a long-term phase stability of 2.5×10−4π rms over four hours, and a spatial phase resolution of 10−3 π with a lateral resolution of 100 μm.

Disclosed is a phase noise compensation apparatus to be applied to the OFDM system, comprising an ICI estimating unit for estimating inter carrier interference (ICI) using a pilot sub-carrier included in a reception signal, a estimating unit for estimating a common phase error (CPE), which is a phase noise from the reception signal as sampled, using the pilot sub-carrier, and estimating a transmission signal by removing the estimated CPE from the reception signal, a calculating unit for calculating phase change by the ICI in the reception signal by convoluting the ICI and the transmission signal, and an equalizer for compensating the calculated phase change by the ICI in the reception signal. Accordingly, phase noise can be exactly compensated by estimating as phase noise the result of convoluting a received signal where the CPE is removed in a frequency domain and the estimated ICI according to the present invention.

The invention relates to a method and system of adopting space phase modulation and interference array to detect the biochip, which belongs to biological technical field. The invention aims to overcome the deficiency of current technique and provides a new biochip detecting method and system, which can detect different volumes of DAN chips and protein chips dispense with mark and real-time achieve the information about the interaction of the biomolecules. The principle of the detection by space phase modulation and interference array is: the light reflected by the biosensor unit entering wallaston prism after combined by the one dimensional magnifying lens, the contained s ray and p ray which is polarizationdirection is divided into the two rays transmitting in different direction and realizing co-lightpath space phase modulation and interference in wallaston prism; the interference fringe being converted into electrical signal through the polarizer and imaging lens, the information of real-time phase change of the each unit on the array chip being acquired after processing and be offered to the biologist and medical scientists to parse.

A quantum cipher communication system includes a sender's apparatus, a recipient's apparatus and a transmission path. The sender's apparatus includes a beam splitting for splitting a laser beam into a weak signal light and an intense reference light, a phase modulation unit for imparting a phase change on either the weak signal light or the intense reference light. The recipient's apparatus includes a phase modulation unit for imparting a phase change on either the weak signal light or the intense reference light, a superimposing unit for superimposing the weak signal light and the intense reference light, a pair of photoconductive diodes for converting two output lights from the superimposing unit into electric signals, and an amplifying unit for amplifying a difference signal between the electric signals, wherein the recipient assigns bit values by comparing the difference signal with threshold values.

A method for adaptive filtering of EEG signals in the wavelet domain using a nearly shift-invariant complex wavelet transform. EEG signal data is segmented into a set of K “trials” or “light averages” of M-frames of data each. These trials are overlapped by a number of frames P, where P<M. A dual-tree complex wavelet transform is computed for each light average K of EEG signal data. Next, the phase variance of each resulting normalized wavelet coefficient is computed, and the magnitude of each wavelet coefficient is selectively scaled according to the phase variance of the coefficients. The resulting wavelet coefficients are then utilized to reconstruct the ABR signal extracted from the EEG data.

A radio receiving apparatus capable of making compensation for both amplitude variations and phase variations and of suppressing image interference in a short period of time is provided.A correction value calculation section (110) combines a signal, obtained by multiplying a first digital signal by an amplitude correction candidate value and rotating the phase of the first digital signal, with a signal obtained by multiplying a second digital signal by a multiplicative inverse of the amplitude correction candidate value and performing, for the second digital signal, phase rotation which is in a quadrature relationship to phase rotation performed for the first digital signal, so as to obtain a first combined signal, obtain an inflection point of the first combined signal, and input, to a demodulation section (120), the amplitude correction candidate value and a phase correction candidate value, which correspond to the inflection point, as an amplitude correction value and a phase correction value, respectively. The demodulation section (120) makes compensation for the amplitudes and the phases and suppresses image interference, based on the amplitude correction value and the phase correction value.

A photo-thermal interferometric spectroscopy system is disclosed that provides information about a chemical at a remote location. A first light source assembly is included that emits a first beam. The first beam has one or more wavelengths that interact with the chemical and change a refractive index of the chemical. A second laser produces a second beam. The second beam interacts with the chemical resulting in a third beam with a phase change that corresponds with the change of the refractive index of the chemical. A detector system is positioned remote from the chemical to receive at least a portion of the third beam. An adaptive optics system at least partially compensates the light beam degradation caused by atmospheric turbulence. A focusing system is used to bring together the light passed through the chemical; the focusing system includes a multimode fiber for the light collection, The detector system provides information on a phase change in the third beam relative to the second beam that is indicative of at least one of, absorption spectrum and concentration of the chemical.

An interferometric profiler is used to measure object motion by modifying the motion of the scanner so that the phase variation at each scanning step is kept within the acceptable limits of the algorithm used to calculate phase changes. The scanner motion is so manipulated on the basis of prior knowledge about the nature of the object motion, or knowledge obtained by pre-calibration, or by real-time feedback based on current measurements. The object motion is recovered from the scanning information by subtracting the scanner position from the object position as it evolves during the scan.

A disturbance, such as vibration from human activity, is located along a fiberoptic waveguide configuration (301-304) with two interferometers (801, 802) of the same or different types, such as Mach-Zehnder, Sagnac, and Michelson interferometers. Carrier signals from a source (101) are split at the interferometer inputs (201, 202) and re-combined at the outputs (701, 702) after propagating through the detection zone (401), where phase variations are induced by the disturbance (501). Phase responsive receivers (901, 902) detect phase relationships (1001, 1002) between the carrier signals over time. A processor (1101) combines the phase relationships into composite signals according to equations that differ for different interferometer configurations, with a time lag between or a ratio of the composite signals representing the location of the disturbance. The detected and composite values are unbounded, permitting phase displacement to exceed the carrier period and allowing disturbances of variable magnitudes to be located.

A method and apparatus for transmitting information combining abrupt phase change modulation with an ultra narrow band filter to remove unnecessary Fourier sidebands, resulting in a single frequency being transmitted to carry data. The method examines and detects the changes in the carrier phase only, after filtering to remove or reduce all sidebands, to obtain a usable signal. Only a single frequency with phase changes is transmitted. An ultra narrow band filter, having a rapid rise time and near zero group delay, passes the near instantaneous modulation changes of phase in the carrier.

The measurement of two separately polarized beams (Ix, Iy) upon diffraction from a substrate (W) in order to determine properties of the substrate is disclosed. Circularly or elliptically polarized radiation is passed via a variable phase retarder in order to change the phase of one of two orthogonally polarized radiation beams with respect to the other of the two beams. The phase change is dependent on the wavelength of the polarized beam. The relative phases of the two radiation beams and other features of the beams as measured in a detector gives rise to properties of the substrate surface.

Provided herein are systems and methods for achieving long coherent integration in a navigational receiver to improve the sensitivity of the receiver and enable the receiver to acquire, reacquire and track signals under very weak signal conditions. In an embodiment, phase compensation is computed based on estimated Doppler frequency, rate of change of the Doppler frequency with time, and second order rate of change of the Doppler frequency. The Doppler frequency may be computed from an orbital model or ephemeris. This phase compensation is used to compensate samples of the input signal for changes in the phase due to the Doppler frequency. Frequency components of the phase-compensated samples are then computed using a frequency analysis such as a Fast Fourier Transform (FFT). The maximum frequency component is taken as an error frequency and used to compensate the samples of the input signal for residual frequency error.

The invention discloses a sound and ultrasonic nondestructive detection method, In the method, the nondestructive detection is carried out on the performance (such as adhesion) of materials such as composites by sound and ultrasonic sensors (such as an electroacoustic transducer made of piezoelectric material, magnetostrictive material, and the like) in a way of direct contact coupling or coupling by a couplant, the single and dual electroacoustic transducers can be excited in the form of continuous waves such as variable sine, pulse or triangle wave, a Phase Sensitive Detection (DSD) technique is adopts to process the change of amplitude and phase of feedback echo, and the detection effect of removing certain interference signals (namely retaining the truth and clearing up the false) can be achieved especially by frequency mixing processing of signals which are collected by different frequencies. The application mechanism of the method adopts currently advanced multifrequency and frequency spectrum analysis technique used for eddy detection to process the information obtained by the electroacoustic transducer, thus obtaining all detection characteristics which the existing noise and vibration detecting does not have.

A bi-directional pulsed ring laser that produces bi-directional light pulses that interact in such a way that they are phase conjugated. A nonlinear substance, such as a nonlinear crystal or fluid, that has an index of refraction that is dependent upon light intensity is located near a beam waist of the laser cavity to provide a self-lensing effect. Methods for reducing dead band beyond observable limits are also provided. The increased sensitivity of the bi-directional pulsed ring laser provides application in detecting magnetic susceptibility by detecting the change in phase between the arrival times of the bi-directional pulses at a modulator and the electrical signal of the modulator to determine the change in frequency of a coil that has magnetic susceptibility.

A phase change material is applied as a very thin film to a transparent substrate such as glass, which material when switched from the amorphous to the crystalline state and back again can affect the reflectivity / transmittance of the combined substrate-coating system. When used with glass panels in the fabrication of relatively large area window glass, the change in spectrally selective transmittance can be used to modulate the amount of sunlight passing through the glass, and thus reduce the amount of cooling required for an interior space in the summertime, and the amount of heating required of that same interior space in the wintertime, while also optimizing the use of visible daylight. Exemplary of a suitable phase change material for glass coating is GeSb or BiSn. Heating of the phase change material to initiate a change in phase can be provided by the application of electric energy, such as supplied from a pulsed power supply, or radiant energy, such as from a laser.