31 results about "Relative attenuation" patented technology

An apparatus and method of processing X-ray projection data including spectral computed tomography (CT) projection data. The spectral CT data is decomposed into material projection lengths using a material-decomposition method that includes an initial-estimate method to provide an initial projection-lengths estimate. The initial-estimate method can include first reconstructing an image using non-spectral CT data, and then subdividing the reconstructed image into materials according to the relative attenuation density of areas within the reconstructed image (e.g., high attenuation areas correspond to a high attenuation material such as bone). The projection length estimates of each material are then obtained by forward projecting the corresponding subdivision of the reconstructed image. Also, the initial estimate can be obtained / refined by selecting the projection lengths with smallest cost-function value from randomly chosen projection lengths within a sample space. The initial estimate can also be conditioned on the X-ray flux at the X-ray source.

Circuits and methods for eliminating or mitigating the amount of temperature-dependent variation in the relative attenuation of a multi-valued digital step attenuator (DSA) by using resistive components having temperature-dependent resistance values that compensate for or offset changes in the temperature-dependent ON resistance (RON) of the switches within the DSA. In some embodiments, DSA attenuator cell switches are fabricated to have positive first-order resistance temperature (FORT) coefficients, while temperature-compensating series attenuation resistances are fabricated as a positive FORT coefficient resistor and temperature-compensating shunt resistances are fabricated as either a negative FORT coefficient resistor or a combination of a negative FORT coefficient resistor in parallel with a positive FORT coefficient resistor.

A large-mode-area (LMA) optical fiber (10) that operates as a single-mode optical fiber. The optical fiber includes a core region (20) surrounded by an inner cladding (32), which in turn is surrounded by an outer cladding (40). The inner cladding includes at least one up-doped ring region (32R1). The ring region is configured to form a large attenuation differential between the higher-order modes and the fundamental mode so only that the fundamental mode remains traveling in the optical fiber. If necessary, the optical fiber can include a bend (10B) having a select “resonant” bend diameter (DB) that increases the relative attenuation of the fundamental and higher-order modes. The optical fiber supports an effective mode field diameter (MFD) of up to 40 μm to 50 μm. As a result, detrimental non-linear effects are suppressed, which allows the optical fiber to carry substantially more optical power than conventional LMA optical fibers. The LMA optical fiber is thus eminently suited for a number of optical-fiber-based applications calling for high optical power, such as fiber lasers and pump sources for wavelength conversion.

The present invention discloses a quick voltage attenuation measuring method and the device thereof for the fuel cell, and belongs to the clean energy technology field. The quick measuring device is used to respectively connect the test circuit of the fuel cell to be tested and the sub-circuit of a reference cell with the in-phase input terminal and the reversed phase input terminal of a differential amplifier, and to connect the output terminal of the differential amplifier with a microprocessor. The quick measuring method is used to first determine the voltage attenuation and the power attenuation as a physical quantity for representing the service life or the durability of the fuel cell, to transform the measuring object from the output voltage of a single-plate or a galvanic pile intothe attenuation or the relative attenuation of the output voltage of the single-plate or the galvanic pile at the front stage, and to measure the attenuation of the output voltage directly, and a normal precise amplifier and a simulated switch can be adopted at the back stage; the output of the differential amplifier can be send to the microprocessor for a further process after being transformed by the modulus, thus the voltage attenuation and the power attenuation of the fuel cell to be tested can be obtained for estimating the service life or the durability of the fuel cell.

The invention provides a method for identifying and suppressing signal resonance interference during microseismic fracture monitoring. The method comprises the following steps: transferring microseismic fracture event signals into a frequency domain; respectively arranging three-component spectrum in terms of horizontal and vertical component; determining the resonance signal band frequency range; selecting a non-resonance interference spectrum channel on the vertical component spectrum arrangement; calculating the energy of a frequency sampling point and that of whole-channel signal master frequency, wherein the ratio of the two energies is a relative attenuation coefficient of the microseismic signal at the sampling point; calculating the master frequency energies of all resonance interference spectrum of each arrangement of the three-component spectrum, allowing the result to multiply the attenuation coefficient of the corresponding sampling point to obtain a spectrum compensation value for resonance interference band frequency compensation; transforming the frequency domain signals to a time domain through an inverted Fourier transform so as to complete suppressing of resonance signals. Due to the adoption of the method, the resonance interference in microseismic signals can be effectively identified and suppressed, so as to minimize the damage for effective signals. Therefore, the method is simple to use and high in calculation efficiency.

A method and system for voice separation based on DUET algorithm is disclosed. The method comprises: receiving signals from microphones; performing a Fourier transform on the received signals (S110); calculating a relative attenuation parameter and a relative delay parameter for each data point (S120); selecting a clustering range for the relative delay parameters based on a distance between the microphones and a sampling frequency of the microphones, clustering the data points within the clustering range for the relative delay parameters into subsets (S130), and performing an inverse Fourier transform on each subsets (S140). It provides an efficient and intelligent solution to deploy DUET on the software and / or hardware.

The invention discloses a wireless network coverage blind area detection method, which comprises the following steps: determining a user position and a user moving speed according to signaling data fed back by a user terminal; removing user data of fast moving users; calculating a relative attenuation value of a medium-low speed user signal; determining the depth fading point according to the relative attenuation value of the user signal, and determining the suspected coverage blind area according to the distribution of the depth fading point. if the suspected coverage blind area is kept in the deep fading state, determining the suspected coverage blind area as the signal coverage blind area. Compared with the existing method, the method of the invention fully utilizes the existing data ofthe operator, can calculate and obtain more accurate user moving speed so as to effectively eliminate invalid user data, and utilizes the relative attenuation value of the user signal, thereby improving the detection precision of covering the blind area and saving manpower and material resources.

The invention belongs to the technical field of tissue optical measurement and relates to a calibration method for a time domain fluorescence chromatography imaging system. The method is used for calibrating transmission factors of each passage of a system and comprises the following steps that: a calibration device used for replacing an imaging cavity in an imaging system is built; a source optical fiber and a detection optical fiber are respectively inserted onto the imaging cavity; some pieces of lens paper are placed into an insertion groove, and the detection optical fiber is connected with the first passage; a 780nm laser is opened, and the attenuation rate of all neutral filters arranged on a filter wheel corresponding to the passage is calibrated; the 780nm laser is turned off, an830nm laser is turned on, and the transmission rate of 830nm long pass filters arranged on a filter wheel corresponding to the passage is calibrated; and the steps are repeated, and the calibration of the relative attenuation rate of all neutral filters arranged on the filter wheel on each passage and the transmission rate of the 830nm long pass filters is completed. The differences on the systempassage transmission performance can be eliminated.

The invention discloses a method for measuring attenuation coefficient of fast and slow shear waves under crack width of rock core. According to the method, by measuring amplitude of fast and slow shear waves before and after fracturing and introducing relative attenuation coefficient, corresponding relative attenuation coefficient of fast and slow shear waves before and after fracturing is calculated, and corresponding relative attenuation coefficient without cracks is subtracted from the relative attenuation coefficient after cracks so as to obtain the influence of cracks on attenuation of fast and slow shear waves. By the method, the influence of anisotropy of a rock sample on attenuation of fast and slow shear waves can be eliminated, and only by considering the influence of crack width on attenuation of fast and slow shear waves, quantitative evaluation of cracks can be realized.

The invention provides a catheter (12) comprising longitudinally spaced acoustic emitters (S1, S2) and receivers (M1, M2, M3) for use in determining the locations of obstructions in an upper airway ofa patient. A plurality of emitters and plurality of receivers are provided, such that, when inserted into an upper airway or oral cavity, the relative attenuation of signals received at each receiverfrom each emitter may be used to determine the existence and / or extent of obstructions located along the propagation path between each of the various emitter-receiver pairs. Also provided are methodsfor determining the locations of obstructions in an upper airway using signals received from acoustic receivers as comprised by catheter arrangements according to embodiments of the invention.

The invention relates to a device used for monitoring hydrocephalus and encephaledema. The device comprises a signal encoding generator, an emission electrode, a receiving electrode, a signal processing digital converter, an orthogonal regulator, a detector, a parameter assessment device, a resistance analyzer and an assessment instrument. The invention also relates to a method used for monitoring hydrocephalus and encephaledema, which comprises the following steps of: intruding into the lower part of the skull skin; emitting electromagnetic waves; carrying out amplification and filter processing on the received electromagnetic waves, and converting the electromagnetic waves into digital signals; carrying out orthogonalization processing on the digital signals; detecting synthetic signals and orthogonal signals of the electromagnetic waves; calculating the relative attenuation coefficients, the relative phase displacement, the transmission time difference and the complex wave value K; calculating the complex impedance Z and capacitance; and assessing hydrocephalus and encephaledema. According to the invention, hydrocephalus and encephaledema situations can be monitored and assessed all day in a non-intrusive mode so as to reduce the treatment risks.

The invention relates to a method for directional signal processing for a hearing instrument, wherein a first input signal is generated from an ambient sound signal, wherein a second input signal is generated from an ambient sound signal, wherein a first and a second input signal are generated The two input signals generate a first calibrated orientation signal having relative attenuation in the direction of the first useful signal source of the environment, wherein, based on the first and second input signals, a second calibrated orientation signal is generated, the second calibrated orientation signal at There is a relative attenuation in the direction of the second useful signal source of the environment, wherein a relative amplification parameter is determined from the first and second calibration directional signals, wherein the first and second processing are generated from the first and second input signals, respectively A directional signal, wherein a source sensitive directional signal is generated from the first processed directional signal, the second processed directional signal and the relative amplification parameter, and wherein an output signal of the hearing device is generated from the source sensitive directional signal.

The invention discloses a quick speed blind source separation method based on frequency point selection under binaural distance. Firstly two problems in using a hybrid signal covariance matrix determinant as a frequency point selection standard are analyzed and a settlement solution is provided. A preliminary selecting solution is provided for selecting some frequency points for performing frequency domain ICA and ordering, and then finally selected frequency points and unselected frequency points are determined through frequency point screening. Furthermore an amplitude uncertainty problem is settled on the selected frequency points for finishing separation. The unselected frequency points are separated by means of a separating matrix which is established by means of a relative mixing parameter that is extracted by a separating matrix on the selected frequency points. The frequency points with relatively high separating performance can be selected through the preliminary selecting solution and a frequency point screening solution secondary selecting process. A separating algorithm for the unselected frequency points has advantages of no limitation by microphone distance, capability of restricting the frequency points for extracting the relative mixing parameter in a frequency range without space overlapping, and no influence of an amplitude uncertainty problem to a relative damping parameter.

The invention relates to a method (2) for operating a hearing aid (4), wherein a first input signal (12) is generated from a sound signal (10) by a first input converter (6), wherein a second input converter (8) generating a second input signal (14) from the sound signal, wherein a first angle and an angle range are preset wherein an attenuation directional signal (28) is formed according to the frequency band by means of the first input signal, the second input signal and the first angle, which having a relative attenuation at least for a second angle in an angular range around the first angle, and thereby determining superposition parameters, by means of the first and second input signals and the superposition parameters and / or the second angle forming an amplified directional signal ( 34) having relative amplification for a second angle, generating an angled directional signal (40) from the attenuated directional signal and the amplified directional signal, and generating an output signal (50) with the angled directional signal.