62results 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 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.

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 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.