2534 results about "Spectral analysis" patented technology

A multi-stage speech recognition system includes an audio transducer that detects a speech signal, and a sampling circuit that converts the transducer output into a digital speech signal. A spectral analysis circuit identifies a portion of the speech signal corresponding to a first class and a second class. The system includes memory storage or a database having a first and a second vocabulary list. A recognition circuit recognizes the first class based on the first vocabulary list to obtain a first recognition result. A matching circuit restricts a vocabulary list based on the first recognition result, and a recognizing circuit recognizes the second class based on the restricted vocabulary list, to obtain a second recognition result.

Methods and apparatus for film measurement and endpoint detection in a noisy environment, such as CMP processing of semiconductor wafers, are disclosed, characterized by the use of spectral analysis of intensity data derived from light reflected off the sample to estimate film thickness or detect an endpoint condition.

A sample element includes first and second substantially parallel faces separated by an intermediate member. The parallel faces and the intermediate member at least partially define a sample chamber configured to hold a volume of fluid. The sample element further includes an optical path extending through the parallel faces and the intermediate member, such that electromagnetic radiation can propagate through the sample chamber. The sample element further includes an identifying compound disposed within or on at least one of the parallel faces. The identifying compound has at least one indexed optical absorbance feature, such that spectral analysis of electromagnetic radiation propagated through the sample chamber yields the indexed optical absorbance feature. Detection of the indexed optical absorbance feature in electromagnetic radiation propagated through the sample chamber indicates to an analyte detection system whether the sample element is configured for use with the analyte detection system.

The present invention provides a diagnostic tool for detection of Cheyne-Stokes Respiration (CSR). This invention also provides a method for development of the diagnostic tool. The method comprises the steps of performing overnight oximetry recordings in patients suspected of sleep disordered breathing. Spectral analysis is performed on the oximetry recordings to obtain a set of parameters which can be used in the construction of a classification tree and a trained neural network. The diagnostic tools of the present invention can be used for classification of a patient as having CSR or obstructive sleep apnea.

A telephone call reception system which infers mental and/or physiological states of callers. Two types of analysis are available, and both types may be used upon the telephone calls. In one type, speech recognition is performed upon the call to generate a text file. Key words are sought in the text file. In the second type, the electrical signal itself is processed, as by a spectral analysis. Information obtained by the two analyses is used to predict the mental or physiological state of the caller.

A handheld ultrasound instrument is disclosed having enhanced diagnostic modes including pulse/continuous wave Doppler, time-motion analysis, spectral analysis and tissue harmonic imaging. An external electrocardiograph (ECG) recording unit is also disclosed. The ECG unit is adaptable to be used with the handheld ultrasound instrument to provide for ECG monitoring while performing an ultrasound scan in B-mode, Doppler, color Doppler, M-mode, and CW/PW mode. The enhanced handheld ultrasound instrument further includes a security mechanism allowing any combination of the diagnostic modes to be enabled by the manufacturer, and later to enable or disable any one or group of the diagnostic modes. The invention also discloses a method for a manufacturer to maintain a database of handheld ultrasound instrument capabilities after the instruments enter the stream of commerce.

A catheter based method and apparatus for reflectance generated absorption spectral analysis of chronic inflammatory vascular conditions such as seen with atherosclerotic plaque within a blood vessel or other body cavity or compartment. The use of a bright mid range infrared light (mid-IR) source yields detectable reflected optical signals that may be sampled from an area smaller or larger than the typical diameter of a mammalian cell. The mid-IR light is delivered at selected mid-infrared wavenumbers. Using the apparatus and methods, the reflectance spectra and reflectance generated absorption spectra of a target tissue can be compared to reference spectra to identify and distinguish normal epithelium from tissue containing physiological markers indicative of vascular disease or other inflammatory conditions.

Systems and methods for using wireless radios for spectral analysis. Systems and methods include using wireless radios that are included in wireless devices communicating on the wireless network to perform a spectral scan of frequencies on a wireless network.

Systems and methods to assist in locating the focus of an atrial fibrillation include the association of atrial fibrillation cycle length values and statistics relating thereto with temporal locations on an electrogram of a given electrode, and/or the coordination of electrode locations with respective the spectral analyses of electrogram signals and further parameters and statistics relating thereto. Ablation therapy can proceed under guidance of such information.

A method for determining a degree of acoustic non-linearity of an earth formation from seismic signals transmitted into the formation from within one wellbore and received from the formation in another wellbore. The seismic signals include two selected discrete frequencies. The method includes spectrally analyzing the received signals, determining from the spectral analysis the presence of a frequency representing a sum of the two selected frequencies, and determining a relative amplitude of the sum frequency with respect to the amplitudes of the two selected discrete frequencies. In a particular embodiment, the method includes determining the presence of a frequency in the spectrally analyzed signals representing the difference between the selected discrete frequencies, and determining the presence of harmonic multiples of one of the two selected discrete frequencies.

A method of multivariate spectral analysis, termed augmented classical least squares (ACLS), provides an improved CLS calibration model when unmodeled sources of spectral variation are contained in a calibration sample set. The ACLS methods use information derived from component or spectral residuals during the CLS calibration to provide an improved calibration-augmented CLS model. The ACLS methods are based on CLS so that they retain the qualitative benefits of CLS, yet they have the flexibility of PLS and other hybrid techniques in that they can define a prediction model even with unmodeled sources of spectral variation that are not explicitly included in the calibration model. The unmodeled sources of spectral variation may be unknown constituents, constituents with unknown concentrations, nonlinear responses, non-uniform and correlated errors, or other sources of spectral variation that are present in the calibration sample spectra. Also, since the various ACLS methods are based on CLS, they can incorporate the new prediction-augmented CLS (PACLS) method of updating the prediction model for new sources of spectral variation contained in the prediction sample set without having to return to the calibration process. The ACLS methods can also be applied to alternating least squares models. The ACLS methods can be applied to all types of multivariate data.

The present invention is directed generally toward the field of spectral analysis and, more particularly, toward an improved method of identifying unknown components of a mixture from a set of spectra collected from the mixture using a spectral library including potential candidates. For example, the present method is directed to identifying components of a mixture by the steps which comprise obtaining a set of spectral data for the mixture that defines a mixture data space; ranking a plurality of library spectra of known elements according to their angle of projection into the mixture data space; calculating a corrected correlation coefficient for each combination of the top y ranked library spectra; and selecting the combination having the highest corrected correlation coefficient, wherein the known elements of the selected combination are identified as the components of the mixture.

Apparatus and methods are provided for the imaging of structures in deep tissue within biological specimens, using spectral imaging to provide highly sensitive detection. By acquiring data that provides a plurality of images of the sample with different spectral weightings, and subsequent spectral analysis, light emission from a target compound is separated from autofluorescence in the sample. With the autofluorescence reduced or eliminated, an improved measurement of the target compound is obtained.

The system and method for spectral analysis uses a set of spectral data. The spectral data is arranged according to a second dimension, such as time, temperature, position, or other condition. The arranged spectral data is used in a signal separation process, such as an independent component analysis (ICA), which generates independent signals. The independent signals are then used for identifying or quantifying a target component.

A method is disclosed for determining movement mode in a drill string. The method includes measuring lateral acceleration of the drill string, determining lateral position of the drill string from the acceleration measurements, and determining mode from the position with respect to time. Also disclosed is a method including measuring drill string acceleration along at least one direction, spectrally analyzing the acceleration, and determining existence of a particular mode from the spectral analysis. Also disclosed is a method for determining destructive torque on a BHA including measuring angular acceleration at at least one location along the BHA, and comparing the acceleration to a selected threshold. The threshold relates to a moment of inertia of components of the BHA and a maximum torque applicable to threaded connections between BHA components. A warning is generated when acceleration exceeds the threshold.

A linearizer reduces nonlinear intermodulation distortion in radio frequency and microwave systems by first directly generating in-phase and quadrature nonlinear intermodulation products of the system input. Controllable amounts of each phase are then added back into the system such that the vector sum of nonlinear intermodulation products at the output is reduced or eliminated by destructive interference, while the fundamentals are substantially unaffected. The quadrature distorted signals are generated with two lightly-biased and thus overdriven differential pairs having gain-determining degeneration impedances that are in quadrature with each other. The amount of each quadrature phase summed to the output is controlled with electronically tunable four-quadrant variable attenuators. The quadrature phasing enables rapidly convergent tuning to minimize distortion using conventional scalar spectral analysis. The advantages of a linearizer using rectangular vector coordinate system are significant.