63results about How to "Large dynamic measuring range" patented technology

The invention discloses a rubidium atomic magnetometer and a magnetic field measuring method. Based on the principle of nonlinear magneto-optic rotation, and through combination of timing control and tracking type frequency locking control, the atomic magnetometer achieves a large dynamic measurement range, high magnetic field sampling rate and high sensitivity. A DSP timing control module controls on-off of an acousto-optic modulator and a radio-frequency signal source in the physical part of the rubidium atomic magnetometer according to timing combination to adjust the magnetic field sampling rate N. The DSP timing control module further controls acquisition triggering of a data acquisition card. A calculation unit gets the Larmor precession frequency (f) through fast Fourier transform with use of a received rubidium atom Larmor precession free relaxation signal, and further calculates the value of an external magnetic field. The calculation unit selects a high magnetic field sampling rate module or a low magnetic field sampling rate module before measurement according to the pre-judged dynamic range of a to-be-measured magnetic field, and sets whether a tracking type frequency locking work mode is used when the low magnetic field sampling rate module is selected. In the working process, data is acquired and processed, and the value of the magnetic field is output.

The invention discloses a signal conversion device for an accelerometer in a strapdown inertial navigation system. An analog current signal output by the accelerometer is converted into an analog voltage signal; the analog voltage signal is subjected to integration by a voltage-to-frequency (V / F) conversion module; one path of analog voltage subjected to integration is output to a pre-amplification circuit, and the other path of analog voltage subjected to integration is converted into a pulse signal and the pulse signal is output to a field programmable gate array (FPGA) processing module; the pre-amplification circuit matches a range of the input analog voltage with an input voltage range of an analog-to-digital (A / D) conversion module; the A / D conversion module converts the analog voltage into a digital value signal and outputs the digital value signal to the FPGA processing module; the FPGA processing module acquires number of pulses output by the V / F conversion module in unit time, the number of the pulses is used as an integer part for calculating the number of pulses, the acquired number of pulses and the digital value signal input by the A / D conversion module are stored in fixed time, and a decimal value of the number of pulses in an acquisition period corresponding to the digital value signal is calculated; and a digital value corresponding to the analog current signal output by the accelerometer is determined according to the integer part and the decimal value of the number of pulses, so that the signal of the accelerometer is converted.

The invention relates to a large-dynamic-range omnibearing sample BRDF (bidirectional reflectance distribution function) measuring device. Two semi-circular arc rails are in coaxial symmetrical installation; a sample is arranged in the center of the semi-circular arc rails; rotating shafts arranged at the two ends of the semicircular arcs are positioned on the same connecting line; the connecting line is positioned in the sample plane and passes through the center of the sample; the center of each semicircular arc is rotationally connected with a linear pull rod, and the other end of each linear pull rod is connected with a slide block; each slide block is arranged on the corresponding linear guide rail, and can move along the corresponding linear guide rail for driving the corresponding semi-circular rail to rotate; the two linear guide rails are symmetrically arranged in the sample plane; the center line of the linear guide rails is vertical to the rotating shafts of the semi-circular arcs; a detector module comprises a photodiode and a photomuitplier dual detector; the photosensitive surface connecting line is vertical to the rotating shafts of the semi-circular arc; the system uses a semiconductor laser; the circular arc rails and the linear guide rails are provided with scales; the sample can realize two-dimensional transverse moving and 360-degree rotation when being put on a three-dimensional moving platform; the light source and detector full-space angle accurate metering scanning can be performed; the high-reliability full-automatic measurement of the sample BRDF can be realized.

The invention relates to an optical fiber current sensor and a manufacturing method thereof. The optical fiber current sensor comprises a first quarter wave plate, a second quarter wave plate, a sensing optical fiber and a coil frame, wherein the first quarter wave plate and the second quarter wave plate are communicated through the sensing optical fiber; the sensing optical fiber is coupled with a half-wave plate; and double wires of the sensing optical fiber double wire are wound on the coil frame in the same direction. The invention provides an optical fiber current sensor which has the advantages of high precision, small volume, light weight and no sensitivity to vibration or rotation due to no Sagnac effect and a manufacturing method thereof.

The invention discloses a device and method for detecting acceleration on the basis of back scattered light of nano particle detection. The device comprises a reflective mirror, a light reducing plate, a beam splitter, a light filer, a first focusing lens, first nano particles, second nano particles, grinding taper optical fibers, a rigid connecting rod, a second focusing lens, pinholes, a separating light detector, a laser, a collimating lens, a light intensity modulator, a DSP processor and a micro circulation channel. The device and method for detecting the acceleration on the basis of the back scattered light of the nano particle detection are based on highly sensitive nanoscale displacement measurement, the structure can obtain extremely high measurement resolution of the acceleration and is only restricted by the absolute value of restoring force of light pressure, and meanwhile, a loop-locked control circuit can extend a dynamic measurement range greatly. According to the device and method for detecting the acceleration on the basis of the back scattered light of the nano particle detection, the acceleration of nanoscale displacement is measured without physical contact, the device is not sensitive to other kinds of acting force not in the acceleration direction, and the device and method for detecting the acceleration on the basis of the back scattered light of the nano particle detection have the advantages of being low in noise, high in sensitivity and capable of carrying out high precision identification and analysis, and having feedback functions.

The invention discloses a nonzero-digit interference system based on a point source array. The nonzero-digit interference system comprises a Twyman-Green interference system, a gradient compensating module, a free-form surface to be tested, an collimating lens, a diaphragm, an imaging lens and a CCD (Charge Coupled Device), wherein the optical parameter of the point source array is determined according to the parameter of the free-form surface to be tested; mathematical relationships between the optical and structural parameters of a lens array, an collimating lens group and a spherical compensating lens group are determined according to each obtained parameter of the point source array; three optimal solution evaluation standards are given, and an optimal optical parameter and an optimal structural parameter of the gradient compensating module are determined in combination with the parameters. Different zero-digit compensators do not need to be designed according to different testing surfaces, and the nonzero-digit interference system is a general free-form surface shape measuring system which ensures high efficiency and high speed while realizing high-precision measurement; meanwhile, a self-collimating light path satisfying zerodigit compensation is not needed, and the advantage is more remarkable specific to surface shape measurement with great gradient change.

The invention discloses a method and a device for detecting laser wavelength based on Rayleigh Brillouin scattering. The Rayleigh Brillouin scattering spectrum in a certain scattering direction is obtained by measuring a Rayleigh Brillouin scattering signal produced by the interaction between laser of which the wavelength is to be detected and high-pressure gas, and the wavelength of the laser tobe detected is obtained according to the frequency shift of the Brillouin peak. Wavelength detection of laser from ultraviolet to infrared can be realized by using one set of device. Moreover, the device can control the temperature and pressure of gas in a scattering pool according to whether the wavelength to be detected is in the ultraviolet, visible light or infrared band to optimize the measurement of spectral Brillouin frequency shift and signal intensity. The signal intensity and spectral resolution can be improved, and it can be ensured that the detection result is highly accurate. . The invention mainly describes a device for realizing laser wavelength detection by using spontaneous Rayleigh Brillouin scattering.

The invention relates to a passive electronic voltage transformer, and belongs to the technical field of electronic voltage transformers. The passive electronic voltage transformer comprises a capacitive voltage divider, an all-fiber current transformer and a data processing unit, and the all-fiber current transformer is used to the leakage current of the capacitive voltage divider and indirectly detect the voltage. The passive electronic voltage transformer can effectively overcome defects of a present electronic voltage transformer, power supply is not needed in the high-tension side, the problem of magnetic saturation does not exist, and the passive electronic voltage transformer also has the advantages including low cost, high response speed, high measuring linearity, wide measuring dynamic range, high measuring precision, high transient performance, high reliability and high stability.

The invention is an optical fiber Fourier transform white light interference relative measurement method, relates to optical fiber sensor technology, and belongs to the field of optoelectronics. In this method, two Fabry-Perot interferometric (FPI) sensors are selected, one of which is used for sensing and the other is used as a reference; the output white light spectrum of FPI is respectively detected and Fourier transformed, and the Fourier spectrum is carried by the frequency determined by the length of the FPI cavity. Frequency, separated into two groups of symmetrical carrier frequency components in the frequency space; one group of components is filtered out for inverse Fourier transform, the two groups of results are conjugated and multiplied to take the complex logarithm, and the phase difference information of the two FPIs is used as the signal The imaginary part of is separated from the background formed by the spectral profile of the light source and the contrast of the interference fringes, enabling the measurement. Compared with the white light spectrum peak measurement method and the Fourier transform peak frequency measurement method, the measurement accuracy of the method of the invention is greatly improved.

Disclosed is a precision defocus detection device and method. The method comprises the steps of constructing a defocus detection light path, implementing a defocus detection algorithm, detecting and compensating for the defocus amount, recording data and the like. According to the requirement for dynamic range and precision of a system, different light paths are designed, different micro-objectives and cylindrical mirrors are selected, and the different precisions and dynamic ranges can be obtained by changing the distance among the micro-objectives, the two cylindrical mirrors and a four-quadrant detector. When a sample is defocused, light spot patterns reflected on the detector change, formed defocused error signals change, and the precise defocusing amount is obtained through the relation between the defocusing amount and the defocusing error signals. The method is widely applied to defocusing detection in the fields of laser direct writing lithography and large-area microscope confocal scanning imaging, the focusing amount in the system running process can be precisely detected and compensated for in real time. The method is easy, practical and convenient to implement and has the high application value.

This invention is related to an apparatus which incorporates a microfabricated silicon mass flow sensor to measure city gas flow rate in a medium pressure range for utility industry which is dominated by conventional mechanical meters such as turbine and rotary meters. The microfabricated mass flow sensor is so called micro-electromechanical systems (a.k.a. MEMS) device. Due to the small feature size of micro scale for MEMS mass flow sensor, the invented apparatus includes many advantages such as low power consumption, compact package, high reliability and extended dynamic measurement range. This apparatus is also provided with a stable flow conditioning to achieve a desired dynamic range capability. Furthermore, because of the high accuracy characteristic, the apparatus in this invention could be applied tot custody transfer or tariff in utility industry as well.

The chip applied in system is finished by very high speed IC hard ware description and is realized based on programmable gate array. The designed software of the chip comprises five parts of system control module, input module, acoustic pressure level spectrum analysing module, total acoustic pressure level calculating module and output module. The present invention not only can fulfil real time processing for noise signal but also can fulfil real time analysing at the same time for the acoustic pressure level spectrum and the total acoustic pressure level of one route noise signal, so it can be used in fabrication of semiconductor.

Provided are a method and device for comprehensively controlling parameters of a high-adaptability optical fiber vibration sensing system. The device comprises a light source module and a comprehensive parameter control module, an output interface of the light source module is connected with an optical fiber path, an output interface of the optical fiber path is connected with an optical receiver, an output interface of the optical receiver is connected with a gain-controllable amplifier, an output interface of the gain-controllable amplifier is connected with a target event filtering module, an output interface of the target event filtering module is connected with an analog-digital conversion module, an output interface of the analog-digital conversion is connected with the comprehensive parameter control module, a circuit control digital voltage output interface of the comprehensive parameter control module is connected with a circuit parameter adjusting module, a light source control digital voltage output interface is connected with a light source parameter adjusting module, an output interface of the circuit parameter adjusting module is connected with the gain-controllable amplifier, an output interface of the light source parameter adjusting module is connected with the light source module, two closed loops are formed by the whole device, and closed loop parameter control is achieved.

The invention discloses an acoustic-electric imaging logging instrument. The acoustic-electric imaging logging instrument comprises a resistivity imager for logging and a sound wave imager, wherein the resistivity imager and the sound wave imager are positioned on one instrument, the resistivity imager is positioned at the upper part of the sound wave imager, and an upper centralizer, a direction short joint, a universal joint and a lower centralizer are sequentially connected between the resistivity imager and the sound wave imager. The acoustic-electric imaging logging instrument has the advantages that the problem of the resistivity imager and the sound wave imager not in the same instrument in the prior art is solved, the two logging maps of resistivity imaging and sound wave imaging can be completed by one tool through one-time logging, the construction period is shortened, the cost is reduced, and the risk of engineering accidents is decreased.

A spectrophotometer comprises a light source module, a reference light module, a resonant cavity module, a sample module and a photoelectric detection module. The spectrophotometer has the advantages of large dynamic measuring range, high detection precision and high repeatability precision, and wide application prospect is achieved.

The invention discloses a pulse width double-moment-adding acceleration sensor circuit which comprises a meter head and a closed-loop feedback control circuit. The closed-loop feedback control circuit comprises a differential capacitance detection circuit, a digital control circuit and a pulse width double-moment-adding feedback loop. The differential capacitance detection circuit is connected to a differential capacitance sensor of the meter head. The digital control circuit receives voltage quantity outputted by the differential capacitance detection circuit, converts the voltage quantity into a digital quantity, thus generates a control quantity, and then converts the control quantity into a double-path PWM wave. The pulse width double-moment-adding feedback loop receives the double-path PWM wave and generates corresponding pulse current. The pulse current is loaded to a moment device of the meter head. The moment device generates corresponding feedback force to balance a detection mass block of the meter head. According to the circuit, the pulse width double-moment-adding feedback loop is used, a disadvantage that the dynamic measurement range of a pulse moment adding feedback loop is insufficient is overcome, and the improvement of the measurement resolution of the pulse width moment-adding acceleration sensor is facilitated.

The invention provides a short-pulse laser coherent combining system which comprises an error detection unit, a signal processing unit and an error compensation unit. The error detection unit is used for detecting cross-correlation signals and interference light intensity information of short-pulse laser in real time, and the signal processing unit is used for processing the cross-correlation signals and the interference light intensity information to obtain control signals required by compensating errors; the error compensation unit is used for generating the corresponding action under the action of control signals and compensating the errors between the short-pulse laser in real time so that the co-phase output of the short-pulse laser is realized. The short-pulse laser coherent combining system provided by the invention can be used for the coherent combination of the short-pulse laser, obtaining the laser with ultra-high power density, and creating conditions for substance characteristic studies under extreme conditions and high-field physics experiments.

The invention discloses an optical fiber temperature sensing device, which comprises a photoelectric modulation unit, a beam splitting unit, a first branch, a second branch and a beam combining unit, and is characterized in that the photoelectric modulation unit, the beam splitting unit, the first branch and the beam combining unit form a first oscillation circuit, the first oscillation circuit is used for realizing oscillation of a first microwave signal, the photoelectric modulation unit, the beam splitting unit, the second branch and the beam combining unit form a second oscillation circuit, the second oscillation circuit is used for realizing oscillation of a second microwave signal, a resonant wave is acquired through performing superposition processing on the first microwave signal and the second microwave signal, the oscillation peak of the resonant wave shifts when a temperature signal is loaded to a sensing region in a second optical fiber, and demodulation for the temperature signal can be realized through acquiring intensity variations of the resonant wave at a fixed frequency. The optical fiber temperature sensing device provided by the invention is high in sensitivity, high in anti-interference ability, low in phase noise, wide in measurement range and simple in demodulation, and can be applied to optical fiber communication.

The invention discloses a double-ring parallel resonant gyro system and a double-closed-loop digital demodulation method thereof. The system comprises a tunable laser, outgoing light of the tunable laser is split into clockwise light and anticlockwise light through a signal beam splitter, the clockwise light and the anticlockwise light sequentially enter an acousto-optic frequency shifter, an electro-optic modulator, an optical fiber coupler, a hollow photonic band gap optical fiber resonant cavity, a photoelectric detector and a digital lock-in amplifier respectively, and frequency closed-loop feedback is formed through the tunable laser and the acousto-optic frequency shifter respectively. According to the double-ring hollow photonic band gap optical fiber structure, clockwise and anticlockwise light waves are respectively propagated in the independent resonant cavities without mutual influence, so that the temperature stability is improved, and nonreciprocal effect noises such as anoptical Kerr effect, Rayleigh backscattering and the like are effectively inhibited. According to the double-closed-loop digital demodulation method, optical frequencies in a clockwise optical path and an anticlockwise optical path are locked at respective transmission resonant frequencies, so that the system works in a linear region, and the linear range of angular velocity detection of the system and the linearity of a scale factor are effectively improved.

The invention provides a power measuring circuit which comprises a differential amplification circuit, a filter circuit, a peak value retaining circuit, an analog-digital conversion circuit and a micro-control component. The differential amplification circuit differentially outputs electric heating signals at two ends of a pyroelectric detector, the filter circuit extracts effective signals from the signals output by the differential amplification circuit and restrains the noise overlaid on the signals of the differential amplification circuit to increase signal to noise ratio, the peak value retaining circuit extracts the amplitude information of the effective signals, the analog-digital conversion circuit converts the amplitude information of the effective signals into digital signals and transmits the digital singles to the micro-control component, and the micro-control component controls the analog-digital conversion circuit and adjusts the amplification times of the differential amplification circuit. The power measuring circuit has the advantages that strong signals can be detected while measuring accuracy of weak signals is guaranteed, and the dynamic measuring range of the system is increased.

The invention provides a Shack-Hartmann wavefront detection method based on region detection and reconstruction. The Shack-Hartmann wavefront detection method comprises the following steps: dividing amicrolens array into a plurality of detection regions, wherein each detection region comprises a plurality of detection sub-apertures; overlapping at least one row or one column of detection sub-apertures among different detection areas, so that complete coverage of the detection regions on the whole wavefront is ensured; selecting one detection sub-aperture in each detection region to serve as areference sub-aperture, enabling different detection areas to carry out correlation operation and inclination extraction on sub-aperture images in the areas based on different reference sub-apertures, and enlarging the dynamic measurement range of Shack-Hartmann on the premise that it is ensured that a correlation algorithm is effective; performing correlation operation and inclination amount extraction on other sub-aperture images in the detection regions and the reference sub-aperture image to obtain inclination of the detection wavefront; and solving the wavefront aberration according to the obtained inclination of the detection wavefront. The scheme can be applied to the field of extended target detection, and can effectively improve the dynamic measurement range of Shack-Hartmann.

The invention discloses a signal conversion device for an accelerometer in a strapdown inertial navigation system. An analog current signal output by the accelerometer is converted into an analog voltage signal; the analog voltage signal is subjected to integration by a voltage-to-frequency (V / F) conversion module; one path of analog voltage subjected to integration is output to a pre-amplification circuit, and the other path of analog voltage subjected to integration is converted into a pulse signal and the pulse signal is output to a field programmable gate array (FPGA) processing module; the pre-amplification circuit matches a range of the input analog voltage with an input voltage range of an analog-to-digital (A / D) conversion module; the A / D conversion module converts the analog voltage into a digital value signal and outputs the digital value signal to the FPGA processing module; the FPGA processing module acquires number of pulses output by the V / F conversion module in unit time, the number of the pulses is used as an integer part for calculating the number of pulses, the acquired number of pulses and the digital value signal input by the A / D conversion module are stored in fixed time, and a decimal value of the number of pulses in an acquisition period corresponding to the digital value signal is calculated; and a digital value corresponding to the analog current signal output by the accelerometer is determined according to the integer part and the decimal value of the number of pulses, so that the signal of the accelerometer is converted.

The invention discloses a common-light-path type multiple inclined wave surface compensation nonzero-digit interference measurement device which comprises a Fizeau interferometer, a standard optical flat, a free-form surface gradient compensation module and a free-form surface to be measured. A primary optical axis of the free-form surface gradient compensation module coincides with a primary optical axis of the interference measurement device, a parallel light beam emitted by the Fizeau interferometer passes through the standard optical flat and is divided into two light beams, one light beam is reflected by the surface of the standard optical flat back to the Fizeau interferometer to be used as reference light, the other light beam enters in the free-form surface gradient compensation module and is emitted out of the free-form surface gradient compensation module, and testing light beams with different inclined angles are formed to irradiate the free-form surface to be measured in an incident mode, are reflected by the free-form surface to be measured back to the free-form surface gradient compensation module, finally are emitted out of the free-form surface gradient compensation module and return to the Fizeau interferometer to form test light. According to the test, high-precision measurement on the optical free-form surface large in local gradient and transportability modularization on the measurement device are achieved simultaneously.

The invention discloses a variable diameter microfiber ring based optical micromechanical acceleration sensor and method thereof, which uses diameter variable ring produced by a microfiber with a diameter of 1~25 micron drawed in a standard single-mode fiber by laser heating taper-drawing technique after removing the coated layer of fiber. The microfiber connected with the standard single-mode fiber through a graded taper transition area is disposed as a diameter variable ring, and the two microfiber of microfiber ring crossing are kept axially parallel, one of which is mounted on the movable mass block of sensing acceleration, while another is mounted on the silicon substrate. The input end of the standard single-mode fiber is connected with wide-spectrum light source, the output end is connected with the fiber spectrometer, and the sensing to acceleration is realized by using diameter variable microfiber ring as high-sensitivity sensing member. The invention is capable of improving measurement precision and stability of optical micromechanical acceleration sensor and increasing dynamic measurement range.

The invention relates to a multi-field sun photometer which comprises an industrial personal computer, a base box and an optical tracking platform. The industrial personal computer is internally equipped with an image acquisition card, a motion control card, an I / O control card and a signal acquisition card. The base box is internally equipped with modular power supplies, a motor driver, an I / O port driver circuit, a constant temperature controller and a signal gain control circuit. The optical tracking platform comprises a CCD detector, a stepper motor, a photoelectric detector, a constant temperature room, and tracking and signal light tubes. The image acquisition card and the CCD detector are connected through the modular power supplies. The motion control card is connected with the stepper motor through the motor driver. The I / O control card is connected with the photoelectric detector through the I / O port driver circuit, and the I / O control card is connected with the constant temperature room through the constant temperature controller. The signal acquisition card is connected with the tracking and signal light tubes through the signal gain control circuit. The double-tube multi-field sun photometer is of high measurement precision, and the intensity ratio of different fields can reflect the change in cloud condition.

The invention relates to a liquid refractive index sensing method and a liquid refractive index sensing device. The method comprises the following steps: enabling broadband probe light to pass through a hollow Bragg fiber filled with a liquid, wherein the hollow Bragg fiber comprises a hollow fiber core, a cladding and a protective layer, the cladding is of a plurality of periodic structures, the periodic structures contain a plurality of normal periodic structures formed by a first dielectric layer and a second dielectric layer and a defected periodic structure formed by a first dielectric layer and a defect layer, the refractive index of the defect layer is greater than or equal to that of the first dielectric layer, and the refractive index of the first dielectric layer is greater than that of the second dielectric layer; obtaining the transmission spectrum of the broadband probe light passing through the hollow Bragg fiber, and then obtaining a resonant wavelength generated by mutual coupling of a defect mode and a fiber mode in the hollow Bragg fiber; using the resonant wavelength as a characteristic wavelength, and realizing the refractive index sensing of liquid to be detected based on a linear relation of the characteristic wavelength and the refractive index of the liquid to be detected. High sensitivity can be maintained, and meanwhile a relatively large liquid refractive index dynamic measurement range is obtained.

The invention discloses a metering type optical current and voltage combined transformer harmonic analysis device and method, and relates to the technical field of power quality harmonic analysis. Thedevice comprises a passive optical current transformer, a passive optical voltage transformer, a merging unit and a secondary side harmonic analyzer; the input end of the merging unit is a digital interface of the passive optical current transformer and the passive optical voltage transformer, the output end of the merging unit is a digital interface of the secondary side harmonic analyzer, and the merging unit is used for merging and outputting digital quantity of three-phase voltage and three-phase current signals. According to the device and method, the characteristics that the side lobe peak attenuation speed of the Nuttall window is high and the main lobe of the Hanning window is narrow are utilized, and the advantages are further improved after self-convolution. Double spectral lineinterpolation and numerical fitting correction are carried out, so that the harmonic analysis precision is greatly improved, and hardware programming realization is facilitated. The method is suitable for the technical field of harmonic analysis.