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78 results about "Wavelength modulation spectroscopy" patented technology
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In wavelength modulation spectroscopy (WMS) for measuring the concentration of a gas component in a gas sample a portion of the light of a tunable light source, usually a continuously tunable laser such as a diode laser, is passed through a reference gas comprising the known gas component or another suitable gas component of constant concentration.
Device for optical monitoring of constituent in tissue or body fluid sample using wavelength modulation spectroscopy, such as for blood glucose levels
InactiveUS7356364B1Improve signal-to-noise ratioReduce calculationMedical devicesCatheterConcentrations glucosePhotodetector
A device for monitoring the concentration level of a constituent in tissue or a body fluid sample, such as glucose concentration in blood, has a laser light source which is modulated about a center emission frequency to probe the absorption spectrum of the constituent being monitored, a laser driver circuit for tuning and modulating the laser light, a photodetector for detecting light from the laser light source transmitted through the sample as the modulation frequency of the laser is tuned, and a demodulator for demodulating the transmitted light and detecting variations in magnitude at harmonics of the modulation frequency to assess the concentration level of that constituent. The device utilizes short-wavelength near-infrared laser light to monitor blood glucose levels, and could also be used for drug screening and diagnosis of other medical conditions as well. In one embodiment, the device is used to monitor blood glucose level externally from the body and non-invasively by trans-illumination through a thin layer of skin, without the need for physical penetration of the skin. In another embodiment, the device is used as an intravenous sensor deployed through a catheter, and its output can be used to control an insulin pump to stabilize the patient's blood glucose levels.
Owner:UNIV OF HAWAII
Apparatus and method of remote gas trace detection
Owner:GAS TECH INST
Laser infrared gas analyzer based on TDLAS-WMS (tunable diode laser absorption spectroscopy-wavelength modulation spectroscopy)
ActiveCN102706832AAdjustable temperatureAvoid damageColor/spectral properties measurementsWater vaporData acquisition
The invention belongs to the technical field of gas detection and relates to a laser infrared gas analyzer based on TDLAS-WMS (tunable diode laser absorption spectroscopy-wavelength modulation spectroscopy) for detecting hydrogen chloride, methane, carbon monoxide, water vapor and other gases. The laser infrared gas analyzer comprises a laser, a laser driving circuit, a temperature control circuit, an optical system with an optical cavity, a main detector, a reference detector, an intensity modulation and canceling circuit, a phase-locking and amplification circuit and a data acquisition and display circuit, wherein the laser driving circuit and the temperature control circuit are used for controlling the laser to emit light, the two ends of the optical system are respectively connected with the laser and the detector, the intensity modulation and canceling circuit is used for canceling the influence of intensity modulation in the system, the phase-locking and amplification circuit is used for extracting harmonic signals, and the data acquisition and display circuit is used for displaying the concentration of the gas to be detected. Compared with other detection instruments, the laser infrared gas analyzer has the advantages that division operation is introduced into the intensity modulation and canceling circuit, and the laser infrared gas analyzer is combined with a space double-optical path differential detection method, so that the influence of the intensity modulation can be fundamentally canceled.
Owner:JILIN UNIV
Gas parameter online measurement method based on wavelength modulation spectroscopy
ActiveCN102680020ASuppress background noiseHigh measurement accuracyColor/spectral properties measurementsWavelength modulation spectroscopyHarmonic
The invention relates to a gas parameter online measurement method based on wavelength modulation spectroscopy and belongs to the field of tunable diode laser absorption spectroscopy. According to the method, a gas absorptivity function is fitted by using an odd number of harmonic signals of an X axis and a Y axis output by a phase-locked amplifier based on the wavelength modulation spectroscopy, normalization processing is carried out on the harmonic signals of the X axis and the Y axis by using first harmonic background signals so as to eliminate the influence of factors, such as background signal, laser intensity and modulation factor, and then, the temperature, concentration, pressure and spectroscopic constant of gas are directly measured by using the gas absorptivity function. The gas parameter online measurement method based on the wavelength modulation spectroscopy has the advantages that the problem that the wavelength modulation spectroscopy needs to calibrate experimental measuring temperature and concentration and cannot measure the pressure and spectroscopic constant of gas nowadays is solved, and the application range of the wavelength modulation spectroscopy is widened.
Owner:TSINGHUA UNIV
Apparatus and method of remote gas trace detection
InactiveUS6664533B1Radiation pyrometryInvestigating moving fluids/granular solidsWavelength modulation spectroscopyFrequency modulation spectroscopy
This specification discloses a method and apparatus for the mobile and remote detection of a gas, such as methane, in the atmosphere. The apparatus includes a TDL based Light Detection and Ranging (LIDAR) driven at carrier frequency lying within the absorption line of the gas. The apparatus also drives the TDL with a modulation frequency to generate upper and lower sidebands in the output of the TDL and with a low ramp frequency to sweep the output of the TDL across twice the width of the pressure-broadened absorption line of the gas, preferably the first overtone absorption line in the case of methane detection. The apparatus include reference and calibration cells or chambers, and includes a light collector and detectors to detect the quantity and modulation of the light that passes the reference or calibration cells and that is received by the apparatus after reflection back toward the apparatus from an uncooperative target. The apparatus further includes a signal processor that applies a derivative spectroscopy technique, such as frequency modulation spectroscopy or wavelength modulation spectroscopy, to determine the presence of the gas in the atmosphere.
Owner:GAS TECH INST
Gas temperature and concentration online measuring method based on first harmonic signal
ActiveCN102680428ASuppress background noiseHigh measurement accuracyColor/spectral properties measurementsWavelength modulation spectroscopyHarmonic
The invention relates to a gas temperature and concentration online measuring method based on a first harmonic signal, which belongs to the technical field of tunable diode laser absorption spectrum (TDLAS). Online measurement of the gas temperature and concentration is realized through the relation between a first harmonic X-axis signal and a first harmonic Y-axis signal and a gas absorption rate functional integral value. The advantages of a direct absorption method in the TDLAS technology are combined with the wavelength modulation method, so that not only is the difficulty that the direct absorption method cannot be applied in a worse environment and a weak absorption condition solved, but also the difficulty that the gas temperature and the gas concentration are determined through a calibration experiment in the measurement of the wavelength modulation method can be solved. Due to the adoption of the method, the measurement precision of the TDLAS technology in the industrial field can be effectively improved, and the application range can be enlarged.
Owner:北京新叶科技有限公司
Wavelength modulation spectroscopy method and system
ActiveUS7116422B2Effectively compensate such transmission variationsRadiation pyrometrySpectrum investigationWavelength modulation spectroscopyHarmonic
In a wavelength modulation spectroscopy method and system the light of a tunable light source is modulated with a frequency f0, while the wavelength is swept over an interaction feature of a sample to be measured. The light of the light source is passed to a sample for interacting and thereafter detected and demodulated at a higher harmonic Nf0.To suppress effects of fluctuations of the optical transmission of the system on the measurement, originating from varying dust loads, high temperature, gas turbulence etc. in the measurement path (3), a burst signal in form of an envelope modulated pilot tone is added to the modulation of the light (1) of the light source (2) synchronously with the wavelength sweeps at a wavelength outside the interaction feature of the sample. The injected burst signal is at the detection frequency Nf0, where N≧2, and is detected together with the measured spectrum from the sample and act as absorption normal, which the spectrum can be calibrated against.
Owner:SIEMENS AG
Wavelength-modulation spectroscopy method and apparatus
In one embodiment of the spectroscopy method, the method comprises the steps of modulating the wavelength of a monochromatic radiation at a modulation amplitude and a modulation frequency; determining a first variable representative of an absorbance of an analyte in a sample; and demodulating by phase-sensitive detection the first variable at a harmonic of the modulation frequency to produce a harmonic spectrum of the analyte. In one embodiment of the spectroscopy apparatus, the apparatus comprises a laser diode integrated with a first photodetector configured to detect an intensity of a backward emission from the laser diode and act as a reference detector; a second photodetector configured to detect an intensity of laser radiation exiting a sample; and electronic circuitry coupled to the laser diode and the photodetectors, configured to acquire and process spectra of the sample. In another embodiment, the spectroscopy apparatus comprises a beam splitter configured to split the laser radiation into a first radiation portion and a second radiation portion and a first photodetector configured to detect the intensity of the first radiation portion.
Owner:GE INFRASTRUCTURE SENSING
Method for measuring gas absorption spectrum line width and line-type coefficient based on wavelength modulation
ActiveCN103323115AEliminate the effects of uncertaintyEliminate the effects ofRadiation pyrometryColor/spectral properties measurementsWavelength modulation spectroscopyHarmonic
The invention discloses a method for measuring the gas absorption spectrum line width and the line-type coefficient based on wavelength modulation. According to the method for measuring the gas absorption spectrum line width and the line-type coefficient based on the wavelength modulation, the specific value between a two-time harmonic and a four-time harmonic in the wavelength modulation spectrum technology are adopted to measure the line width and the line-type coefficient of the spectral line absorbed by the gas. During measurement, the line width and the line-type of the gas absorption spectrum line to be measured are calculated by means of analysis of the specific value between the two-time harmonic and the four-time harmonic. The method for measuring the absorption gas spectrum line width and the line-type coefficient based on the wavelength modulation has the advantages of being easy to operate, high in measuring precision, and capable of eliminating influence of factors such as background signals, laser intensity fluctuation and the photoelectricity amplification coefficient, solving the problem that an existing WMS technology can not accurately measure the line-type parameters absorbed by the gas and broadening the application range of the WMS technology and the like. Due to the fact that the specific value between the two-time harmonic and the four-time harmonic are adopted to calculate the gas absorption line-type parameters, the method for measuring the gas absorption spectrum line width and the line-type coefficient based on the wavelength modulation can be called the R24 method.
Owner:北京新叶科技有限公司
Device, method and system for determining the road surface condition
InactiveUS20060050270A1Radiation pyrometrySpectrum investigationWavelength modulation spectroscopyReflectance properties
The invention relates to a device, a method and a system for determining a road surface condition, where the surface condition is one of dry, wet or icy. The device comprises a reflectance spectrometer which senses the reflectance properties of the road at one or several wavelengths and uses these reflectance properties to determine the surface condition. The reflectance spectrometer is a wavelength modulation spectrometer, preferably for the near infrared region. The system determines the surface condition and indicates it to a user of the system.
Owner:ELMAN ULF
Wavelength modulation spectroscopy for simultaneous measurement of two or more gas ingredients
InactiveUS20100242572A1Reduce measurement errorEasy CalibrationMaterial analysis using wave/particle radiationMaterial analysis using microwave meansGas compositionConcentration ratio
Methods and systems to measure simultaneously concentrations or concentration ratio(s) of two or more gas ingredients in a sample area comprising: a wavelength modulated light source; an acoustic detector or a photodetector; and means to analyze the signal from the acoustic detector or the photodetector and calculate the concentrations or concentration ratio(s). The light from the light source is transmitted through the sample area. Part of the light will be absorbed in the sample area by the gas ingredients and generates photoacoustic signal. The acoustic detector is used to sample the photoacoustic signal. Alternatively, a photodetector is used to sample the light intensity after the light is transmitted through the sample area.
Owner:YU JAMES
Apparatus and method for noninvasive human component measurement with optional optical length
ActiveUS20080171925A1Increase the areaIncrease light intensityPhase-affecting property measurementsDiagnostic recording/measuringHuman bodyPhase sensitive
This specification discloses a method and apparatus for noninvasive measurement of human body component, such as glucose, in vivo. The apparatus includes near infrared spectroscopy based laser sources driven at carrier frequency lying within the absorption line of the component. The apparatus also drive the laser diodes with a modulation frequency to generate frequency difference between the measuring light and reference beam, and the interference of the two beam results in a beat signal, which frequency is proportional to optical path difference between the measuring light and reference beam. We can detect the spectrum of the scattering light, which propagate at specifically single optical path, by select the frequency using a phase sensitive detector (PSD) circuit. The apparatus include several laser sources and its controllers which modulate the laser's radiation, and includes an optical fiber coupler and splitter to split the laser into measuring and reference beam, and includes PSD circuit to detect the signal by the frequency. The apparatus further includes a signal processor that applies a derivative spectroscopy technique, such as wavelength modulation spectroscopy, to determine the concentration of the component in the body.
Owner:TIANJIN SUNRISE TECH DEV
Wavelength modulation spectrum technology-based denitrified ammonia escape rate measurement device and method
ActiveCN104215606AConsistent temperatureAvoid interferenceColor/spectral properties measurementsAir preheaterHigh concentration
The invention relates to a wavelength modulation spectrum technology-based denitrified ammonia escape rate measurement device and method, belonging to the technical field of tunable diode laser absorption spectroscopy. The method is characterized in that laser is split through an optical beam splitter on the basis of quadruple sub-harmonic in the wavelength modulation spectrum technology, a part of laser permeates a high-concentration reference cell to be used for locking a central wavelength and monitoring the zero point of an instrument constantly, and the other part of laser permeates a smoke measurement cavity to be used for obtaining the concentration of an ammonia gas. In an in-situ sampling mode, a sampling rod and the measurement cavity are both arranged in a flue of a denitrified air preheater. The method has the characteristics that with adoption of a low-pressure measurement method, the pressure of the measurement cavity is kept at 0.1atm, a strong absorption spectrum line can be selected and the interference from other gas spectrum lines can be avoided, the sensitivity of the instrument can be improved, and the lower limit of measurement can be lowered. Through the method, a series of problems, caused during application of an existing ammonia escape rate instrument, such as the incapability of laser to permeate dust with high concentration, the deflection of laser resulted from mechanical deformation of a flue wall, the incapability of marking, and blocking of a filtering permeation probe, can be solved.
Owner:TSINGHUA UNIV
Method for simultaneous measurement of high-temperature gas two-dimensional transient temperature field and concentration field
ActiveCN105548072AFast scanningAccurate detectionThermometers using physical/chemical changesColor/spectral properties measurementsLaser arrayWavelength modulation
The invention discloses a method combining hyper-spectrum and wavelength modulation for simultaneous measurement of high-temperature gas two-dimensional transient temperature field and concentration field. The method includes: arranging a laser array in a to-be-measured high-temperature area, and conducting hyperspectral scanning on the to-be-measured area to obtain water vapor absorption spectral line information, and carrying out demodulation with a digital phase lock technology to obtain each harmonic signal, then conducting background deduction first harmonic normalization processing, extracting the maximum amplitude value of the signal to measure regional temperature field and water vapor concentration field, and during measuring, conducting grid discretization treatment on the to-be-measured area, arranging laser beam at each row and each column of the grid to conduct broad spectrum scanning on the characteristic spectral line of the to-be-measured gas under a wavelength modulation mode, and using intelligent optimization algorithm to realize inversion of the temperature field and gas concentration field. The measurement method provided by the invention combines hyper-spectrum and wavelength modulation spectroscopy technologies, and is especially suitable for monitoring of high-temperature gas two-dimensional temperature field and concentration field on harsh industrial sites.
Owner:SOUTHEAST UNIV
Device, method and system for determining the road surface condition
InactiveUS7224453B2Radiation pyrometrySpectrum investigationWavelength modulation spectroscopyReflectance spectroscopy
The invention relates to a device, a method and a system for determining a road surface condition, where the surface condition is one of dry, wet or icy. The device comprises a reflectance spectrometer which senses the reflectance properties of the road at one or several wavelengths and uses these reflectance properties to determine the surface condition. The reflectance spectrometer is a wavelength modulation spectrometer, preferably for the near infrared region. The system determines the surface condition and indicates it to a user of the system.
Owner:ELMAN ULF
Method for Calibration-Free Scanned-Wavelength Modulation Spectroscopy for Gas Sensing
A method of calibration-free scanned-wavelength modulation spectroscopy (WMS) absorption sensing is provided by obtaining absorption lineshape measurements of a gas sample on a sensor using 1 / -normalized WMS-2 / j where an injection current to an injection current-tunable diode laser (TDL) is modulated at a frequency ̂ where a wavelength modulation and an intensity modulation of the TDL are simultaneously generated, extracting using a numerical lock-in program and a low-pass filter appropriate band-width WMS-<< / (n=1, 2, . . . ) signals, where the WMS-<< / signals are harmonics of the f, determining a physical property of the gas sample according to ratios of the WMS-<< / signals, determining the zero-absorption background using scanned-wavelength WMS, and determining non-absorption losses using at least two the harmonics, where a need for a non-absorption baseline measurement is removed from measurements in environments where collision broadening has blended transition linewidths, where calibration free WMS measurements without knowledge of the transition linewidth is enabled.
Owner:THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIOR UNIV
Device and method for measuring gas pressure intensity and component concentration by using wavelength modulation spectrum
ActiveCN107063553AEasy to implementReduce bandwidth requirementsColor/spectral properties measurementsFluid pressure measurement by optical meansWavelength modulation spectroscopyHarmonic
The invention discloses a device for measuring the gas pressure intensity and component concentration by using a wavelength modulation spectrum, and further discloses a method for measuring the gas pressure intensity and component concentration by using the wavelength modulation spectrum. According to the method disclosed by the invention, transmission light intensity signals are processed by using digital phase locking and low-pass filtering based on a wavelength modulation absorption spectrum technology so as to acquire a background deducted secondary harmonic signal and a primary harmonic normalized secondary harmonic signal, a relation between a simulation signal secondary harmonic peak feature and the pressure intensity is established, a relation between a simulation signal primary harmonic normalized secondary harmonic peak value and the concentration is established at the same time, and pressure intensity and component concentration information of a gas to be measured is calculated by adopting an interpolation method. The measuring method disclosed by the invention has the characteristics of non-invasion, high response speed, high sensitivity and the like, and is applicable to measuring the gas pressure intensity and component concentration simultaneously at the industrial field.
Owner:SOUTHEAST UNIV
Method of calibrating a wavelength-modulation spectroscopy apparatus
ActiveUS20100089117A1Radiation pyrometrySpectrum investigationWavelength modulation spectroscopyAnalyte
Several methods of calibrating a wavelength-modulation spectroscopy apparatus configured to measure a concentration of an analyte in a sample gas are disclosed. Each of the methods allows for calibration and recalibration using a relatively safe gas regardless of whether the sample gas for which the concentration of the analyte can be determined is a hazardous gas. In one embodiment of the invention, calibration that is sample-gas specific is accomplished by determining a first slope coefficient and calibration function for the sample gas, after which a scaling factor can be determined based on the first slope coefficient and a second slope coefficient for the same or a different sample gas and used in a subsequent calibration (or recalibration) to scale the calibration function. In other embodiments of the invention, calibration that is not sample-gas specific is accomplished to allow for the determination of the analyte concentration in variable gas compositions and constant gas compositions.
Owner:GE INFRASTRUCTURE SENSING
Flue gas content laser on-line detection method and system
ActiveCN102353633AAccurate measurementAvoid influenceColor/spectral properties measurementsWavelength modulation spectroscopyElectricity
The invention relates to a flue gas content laser on-line detection method and a system. The system provided by the invention comprises a photic driving unit, a light emitting unit, an optical signal detection unit, an electric signal transmission unit, a central control cabinet and an industrial control computer. The method provided by the invention comprises the following steps of: allowing double-frequency modulated laser to pass through a background gas and then pass through a spectroscope, directly receiving the reflected laser by a photo-detector, allowing the laser which passes throughthe spectroscope to travel through flue gas and to be received by another photo-detector; and processing electric signals outputted from the two photo-detectors to obtain the detection signal. By theadoption of the sensing structure of two light beams, the wavelength modulation spectrum technology and the phase lock amplification technology, the technical issue of measurement accuracy by presentoptical gas sensors is improved.
Owner:XIAN YIDA INFORMATION SYST
Calibration-free wavelength modulation spectroscopy gas detection method based on S[2f] method
ActiveCN105372205AAccurate measurementFitting results are accurateColor/spectral properties measurementsWavelength modulation spectroscopyPhase shifted
The invention belongs to the technical field of laser spectroscopy, and mainly relates to a calibration-free wavelength modulation spectroscopy gas detection method based on an S[2f] method. Corresponding scientific analysis shows that A, i[1], i[2], concentration and phase difference psi[1] and psi[2] have little influence on S[2f] / S[2f]<c> signals, and only WMRF has obvious influence on the S[2f] / S[2f]<c> signals. Therefore, under conditions of uncertain concentration and phase shift, WMRF is obtained by inverting the S[2f] / S[2f]<c> signals, and because fitting parameters are greatly reduced, the method can be guaranteed to be simple, rapid and accurate. On the basis, the concentration of to-be-measured gas is fitted, and a measurement value with higher accuracy degree is obtained. The new method is simple, rapid and accurate, and is suitable for wide promotion in the field of gas detection.
![Calibration-free wavelength modulation spectroscopy gas detection method based on S[2f] method](https://images-eureka.patsnap.com/patent_img/d3215de2-2d2d-4de8-98ef-228cd0e97f16/151125160322.png "Calibration-free wavelength modulation spectroscopy gas detection method based on S[2f] method")
![Calibration-free wavelength modulation spectroscopy gas detection method based on S[2f] method](https://images-eureka.patsnap.com/patent_img/d3215de2-2d2d-4de8-98ef-228cd0e97f16/151125160326.png "Calibration-free wavelength modulation spectroscopy gas detection method based on S[2f] method")
![Calibration-free wavelength modulation spectroscopy gas detection method based on S[2f] method](https://images-eureka.patsnap.com/patent_img/d3215de2-2d2d-4de8-98ef-228cd0e97f16/151125160329.png "Calibration-free wavelength modulation spectroscopy gas detection method based on S[2f] method")
Owner:山西博思通电子科技有限公司
Wavelength modulation spectroscopy for simultaneous measurement of two or more gas ingredients
InactiveCN101617192AColor/spectral properties measurementsUsing optical meansPhotodetectorAdditive ingredient
Methods and systems to measure simultaneously concentrations or concentration ratio(s) of two or more gas ingredients in a sample area comprising: a wavelength modulated light source; an acoustic detector or a photodetector; and means to analyze the signal from the acoustic detector or the photodetector and calculate the concentrations or concentration ratio(s). The light from the light source is transmitted through the sample area. Part of the light will be absorbed in the sample area by the gas ingredients and generates photoacoustic signal. The acoustic detector is used to sample the photoacoustic signal. Alternatively, a photodetector is used to sample the light intensity after the light is transmitted through the sample area.
Owner:詹姆斯·於
Gas absorptivity online measurement method based on fast Fourier transform
ActiveCN109696415AReduce distractionsAutomate processingColor/spectral properties measurementsParticulatesFrequency spectrum
The invention discloses a gas absorptivity online measurement method based on fast Fourier transform, and belongs to the technical field of tunable diode laser absorption spectroscopy (TDLAS). According to the method, a sine wave is adopted to modulate the output wavelength of a tunable semiconductor laser, a characteristic frequency spectrum containing absorption information is extracted throughfast Fourier transform on the transmission light intensity, the transmission light intensity is reconstructed, and other frequency noise signal interferences such as particulate matter and light intensity fluctuation can be effectively eliminated; a relationship between the laser light intensity and the wavelength is established based on an intermediate variable eta, and the transmission light intensity obtained by reconstruction is fitted with eta as an independent variable to realize synchronous online measurement of the incident light intensity and the gas absorptivity. The method is simpleand convenient to operate and wide in application range; the problems that a direct absorption method is large in base line fitting uncertainty and a wavelength modulation method cannot accurately measure the absorptivity are solved, and the gas absorptivity measurement precision is effectively improved.
Owner:TSINGHUA UNIV
Method for measuring concentration of a gas component in a measurement gas
ActiveUS20140185035A1Improve accuracyImprove reliabilityRadiation pyrometryScattering properties measurementsWavelength modulation spectroscopySmall amplitude
A method in which the wavelength of the light of a tunable light source is varied periodically over an absorption line of interest for the gas component to measure the concentration of a gas component in a measurement gas based on one of two measurement methods of direct absorption spectroscopy and wavelength modulation spectroscopy and, where in the case of wavelength modulation spectroscopy, the wavelength of the light is additionally sinusoidally modulated at a high frequency and with a small amplitude, where the intensity of the light is detected after transradiation of the measurement gas and processed to yield a measurement result, and where in order to increase the accuracy and reliability of the measurement, the two measurement methods are applied simultaneously during each period, or alternately in consecutive periods, and their results are combined by averaging to form the measurement result.
Owner:SIEMENS AG
Gas Concentration Measurement by 2F Signal Trough Distance
ActiveUS20190195789A1Radiation pyrometryColor/spectral properties measurementsWavelength modulation spectroscopyCalibration gas
A computer-implemented method for measuring gas concentration from a 2f signal in wavelength modulation spectroscopy is presented. The computer-implemented method includes emitting a beam of light from a laser to pass through a gas sample, calculating a gas measurement value from the gas sample via a trough distance calculator using a trough distance of a gas absorption line's 2f signal, calibrating the gas measurement value via a multi-point calibration process, and outputting the gas measurement value to a user interface of a computing device.
Owner:NEC CORP
WMRF new model-based calibration-free wavelength modulation spectrum gas detection method
InactiveCN105388120AImprove Absorption Measurement AccuracyFitting results are accurateColor/spectral properties measurementsSpectroscopyMaterial resources
The invention belongs to the technical field of laser spectroscopy, in particular relates to a WMRF new model-based calibration-free wavelength modulation spectrum gas detection method, and solves the technical problem of low precision of a calibration-free wavelength modulation spectrum technology currently used for gas concentration detection. An etalon of a 0.02 cm<-1> free spectral range is used to analyze wavelength change WMRF caused by signal modulation, a first harmonic component with the amplitude linearly changed and a second harmonic component with an amplitude as a constant are observed, and a new model for describing WMRF is described. By using the new model, a system can acquire a more accurate fitting result; compared with a conventional system, hardware module addition and manual operation are not needed, only program improvement is needed, and development and application are facilitated. The method is simple in technical scheme and convenient in operation, consumption of lots of manpower and material resources is not needed, and the cost and convenience degree in use are easily accepted by most application departments.
Owner:山西镭谱光电科技有限公司
Harmonic wavelet analysis method for modulating spectral signals
The invention discloses a harmonic wavelet analysis method for modulating spectral signals. The harmonic wavelet analysis method is based on the wavelength of a TDLAS, and includes the implementation steps of (1) building a harmonic wavelet equation of the modulated spectral signals of the TDLAS, (2) computing the harmonic wavelet expansion coefficients of the signals with a decomposition algorithm, (3) determining decomposition layer numbers required by signal analysis according to the corresponding relation between wavelet decomposition layer numbers and analysis frequency bands, (4) retaining the harmonic wavelet coefficients of the required frequency bands, and obtaining the signals of the frequency bands through Fourier transformation, (5) constructing an envelope function of the frequency bands, and (6) carrying out an envelope taking process on the signals of the frequency bands to obtain frequency doubling signals of the modulated signals of the TDLAS.
Owner:PLA PEOPLES LIBERATION ARMY OF CHINA STRATEGIC SUPPORT FORCE AEROSPACE ENG UNIV
Method and device for enhancing gas flow rate measurement precision
ActiveCN108008146AHigh resolutionHigh precisionFluid speed measurementWavelength modulationSignal-to-quantization-noise ratio
The invention belongs to the technical field of high speed gas concentration and flow rate measurement, and discloses a method and a device for enhancing gas flow rate measurement precision. Accordingto the method, two even harmonic signals (nf and mf, n,m=2,4,6... and n>m) are simultaneously demodulated by using a phase-locked amplifier through the wavelength modulation spectrum (WMS) technology, nf (WMS-nf / mf) is normalized by mf and narrow and sharp peak signals of high signal-to-noise ratio are obtained, and the gas flow rate is calculated through Doppler frequency shift of narrow peak sothat the measurement resolution and precision can be enhanced. The device is composed of a tunable laser, a photoelectric detector and the phase-locked amplifier. The working steps of the device arethat two beams of laser and gas flow are obliquely incident to the gas flow field with the directions crossed at a certain angle, the emergent laser is received by two detectors and converted into electric signals, the electric signals are demodulated by the phase-locked amplifier and the WMS-nf / mf signals are obtained, and the flow rate of the gas is calculated through Doppler frequency shift ofthe two signals.
Owner:TIANJIN POLYTECHNIC UNIV
Apparatus for measurement of gas concentrations in breath
ActiveCN102264292BQuick checkImprove accuracyRespiratorsMedical devicesFrequency spectrumTemporal resolution
A device for measuring oxygen uptake and carbon dioxide production by a respiring subject based on the use of absorption spectroscopy. An absorption spectrometer using cavity enhanced absorption spectroscopy at 763 nm to measure oxygen concentration and direct absorption or wavelength modulation spectroscopy at 2.0035 μm for carbon dioxide concentration is incorporated into a breathing tube in proximity to the respiring subject. This provides measurements of oxygen and carbon dioxide concentration with a good temporal resolution which can be combined with measurements of flow rate as a function of time to obtain oxygen uptake and carbon dioxide production on a breath-by-breath basis. The device can also measure the concentration of water vapor and of anaesthetic gases in exhaled breath.
Owner:OXFORD UNIV INNOVATION LTD
Device and method for multiple-parameter measurement of combustion state of coal-fired boiler
InactiveCN102654456AReduce total usageSimple structureColor/spectral properties measurementsReference sampleEngineering
The invention discloses a device and a method for multiple-parameter measurement of a combustion state of a coal-fired boiler. The device comprises a central processing module, a light emitting module and a light receiving module, wherein a signal generator, a current controller and a temperature controller in the central processing module can be used for together modulating and driving a diode laser to emit a laser; the laser is transmitted to the light emitting module so as to be expanded in beam and collimated; then, the laser is contacted with gas to be tested in the flue of the coal-fired boiler and then is received and detected by the light receiving module; in addition, the optimal signal is converted into an electric signal which is transmitted to the lock-in amplifier I and the lock-in amplifier II in the central processing module respectively for demodulation; the demodulated signal is sent to a signal processor for analyzing and processing; and finally, an obtained value is displayed on a display screen. According to the device and the method provided by the invention, the system calibration is realized by a laser absorption spectroscopy and by utilizing the ratio of a secondary harmonic signal to a primary harmonic signal, wherein the primary harmonic signal and the secondary harmonic signal are demodulated by wavelength modulation spectroscopy technology; as a result, the use of a reference sample pool is avoided, the system structure is simplified and the system volume is reduced; the system accuracy is less than or equal to plus or minus 1%; and the device is high in accuracy, low in price, long in service life and free from maintenance.
Owner:ANHUI WAYEE SCI & TECH CO LTD
Method for achieving nonuniform combustion field gas parameter quantitative measurement based on modulated spectrum
ActiveCN107036983ASolving Quantitative Measurement ProblemsRealize quantitative measurementColor/spectral properties measurementsLine widthLine strength
The invention provides a method for achieving nonuniform combustion field gas parameter quantitative measurement based on the modulated spectrum technology. The method comprises a wavelength modulated spectrum measurement step, a wavelength modulated spectrum fitting step and a step of calculating gas parameters in a nonuniform flow field. According to the specific content of the method, an absorption spectral line with the line strength linearly changing along with temperature within the measured temperature range is selected; transmission light intensity signals are measured through tests, and harmonic signals measured through the tests are obtained; the integral optical density, Gaussion line width and Lorentz line width are adopted as free variables, and the harmonic signals of the spectral line are fit based on the least square method; the gas parameters in the nonuniform combustion field are calculated.
Owner:PLA PEOPLES LIBERATION ARMY OF CHINA STRATEGIC SUPPORT FORCE AEROSPACE ENG UNIV
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