46results about How to "Improve measurement signal-to-noise ratio" patented technology

The invention discloses a brain-computer interface system based on an atom magnetometer, and a use method thereof. The invention combines the work characteristics of the atom magnetometer to design abrain magnetic cap and a magnetic shielding device with practicality; a scheme of separating an atom magnetometer probe from a light source is adopted to improve a system integration level; system probability is intensified; a brain magnetic signal processing process capable of greatly improving operation speed and reducing processing process complexity; and for scenes which may be applied by thesystem, a feasible commutation and peripheral support system is given. By use of the brain-computer interface system provided by the invention, the control of a local and remote application system isfinished conveniently through the brain magnetic signal, and the system owns practicality and good expansion performance.

The invention relates to a silicon chip surface defect detector capable of classifying defects and a defect classifying method. The flat surface of the silicon chip to be detected on a highly reliablesilicon chip working platform is irradiated by a laser from an inclination direction. Circular narrow channel collection and annular narrow channel collection are carried out on scattered lights produced by the silicon chip surface defect by two paraboloidal mirrors with different calibers in a direction near the silicon chip face normal and parallel with silicon chip face. Two photoelectric detectors detect intensities of the collected electrooptical signals in two channels respectively and then take a ratio of two intensities, then compare the ratio with a given threshold value, and at lastthe silicon chip surface defects can be classified. The defect detector has the advantages of simple structure, high sensitivity, fast detecting speed, capability of classifying the defects on the silicon chip surface, etc.

The invention discloses a device and a method for detecting biological tissue of pressure modulation near infrared spectrum. Biological tissue physiological status judgment and volume difference spectrum measurement are achieved according to pressure and spectrum measuring results in the process of deformation of the biological tissue: changing of biological tissue diffuse reflection spectrum along with the pressure and action time is respectively measured, multiplicative scatter correction and second derivative processing are conducted to the measured spectrum, content change of free water and bound water is obtained, fitting processing is conducted to the content change of the free water and the bound water, the pressure and the action time, biological tissue status is judged according to a fitting curve trend; differential treatment is conducted to diffuse reflection spectrum obtained under different pressure values, the water content change in the tissue is taken as a reference, physiological background of the tissue is deducted, and spectrum net analyte signals of tissue elements are obtained. According to method for detecting the biological tissue of the pressure modulation near infrared spectrum, rapid detecting of physiological status of the biological tissue is achieved, and spectrum detection accuracy of the tissue elements is improved.

The invention discloses a calibration method of absolute response ratio of an infrared detector and a device thereof. By using the method of combining a blackbody origin and a narrow band pass filter, the absolute response ratio parameter of the detector under an appointed wavelength is acquired. According to the method, the blackbody origin is adopted as a calibration light source, so the stability of the uniformity of spatial output light spots is guaranteed; the placement positions of the detectors does not need to be precisely adjusted during calibration measurement, so the calibration efficiency and the precision of batch detectors are greatly improved; and meanwhile, power parameter of light irradiated onto the surfaces of the detectors is acquired through a theoretical calculation method, so errors in the power measurement of weak light signals are overcome. Through changing the wavelength parameter of the pass filter and the blackbody temperature, the method can be applied to parameter calibration of the detectors at various wavelengths, and the applicability is high.

The invention discloses a device and a method for measuring a molecular diffusion coefficient in a gas medium. The device comprises a mark laser, a display laser, an ICCD (Intensified Charge Coupled Device) camera and a delay generator, wherein output laser of the mark laser is shaped as a mark linear laser beam; an output laser beam of the display laser is shaped as a sheet-shaped display laser beam; the mark linear laser beam is arranged in a plane of the sheet-shaped display laser beam; the sheet-shaped display laser beam is positioned in the gas medium to be detected; the ICCD camera directly faces to the sheet-shaped display laser beam; three paths of delay output ends of the delay generator are respectively connected with the mark laser, the display laser and the ICCD camera. The invention establishes a new molecular diffusion observing method. The observation method is capable of accurately measuring the molecular diffusion process under the unstable condition; the observation method can be used for observing the diffusion process of part of the molecules which are not observed by the prior art, thereby measuring the diffusion coefficient of the gas molecule.

The invention discloses a system for testing antenna impedance. The system for testing the antenna impedance comprises a tested antenna, a high-voltage power source, an adjustable inductor L, an inductance and resistance testing module, a data processing module, a controller, a stepping driver, a gathering module, a potential-divider network, a light-operated switch module and a protection resistor. According to a working mechanism, oscillating starting initial high voltage is injected into a self-damping oscillation circuit with the frequency selectable so that self-damping oscillation can be generated; self-damping oscillation physical characteristics are commonly determined by parameters of elements so that the resistance value of the antenna to be tested can be obtained through sampling and calculation conducted on the oscillation voltage. According to the system for testing the antenna impedance, the testing signal-to-noise ratio can be effectively improved and under the actual emitting operating frequency of the antenna, accurate measurement of the antenna impedance is conducted.

The invention provides a method for simultaneously measuring broadband visible light and near-infrared radiation. According to the method, periodically poled crystals are used as nonlinear media, nondegenerate correlated photons (visible light and broadband infrared bands) are generated through the collinear phase matching, meanwhile, the temperature tuning technology of nonlinear crystals is utilized, correlated photon pairs of wide spectrums are generated, a Si single-photon detector and an InGaAs single-photon detector are utilized for realizing the simultaneous absolute measurement of the visible light and the near-infrared band optical radiation, and the measurement uncertainty is higher than 1 percent (k=2).

The invention discloses a sound pressure sensitivity calibration cavity and a testing method thereof. The calibration cavity consists of two rigid cavities which are a standard cavity and a measuringcavity; the standard cavity is a small volume cavity whose internal and external are in cylindrical shapes, and a transmitting transducer and a reciprocal transducer are installed in the standard cavity during measuring, so that the accurate measuring on standard cavity reciprocal constants and the transfer impedance of the transmitting transducer and the reciprocal transducer can be accomplished;and the internal of the measuring cavity is in a cylindrical shape, and the external of the measuring cavity is a triangular rigid cavity, and during measuring, the transmitting transducer, the reciprocal transducer and a measured hydrophone are respectively fixed on three faces of the triangular cavity, located on the central face of the cylindrical inner cavity and in symmetric distribution. The testing method is a four-transducer reciprocity method. The beneficial effects of the calibration cavity and testing method are that through the calibration by using the double coupled cavity and the four-transducer reciprocity method, the measuring precision of low frequency sound pressure sensitivity can be enhanced, and the measuring on the phase of the hydrophone in the coupled cavity can berealized.

The invention relates to a semiconductor laser distance measuring device based on switched capacitor array sampling. The distance measuring device comprises an emission end and a receiving end which are connected with a main control module. The emission end successively comprises an LD driving module, an LD module and an LD shape adjusting emission module. The receiving end successively comprises an echo receiving module, an APD amplifying module, an SCA sampling integration module and an ADC module. The SCA sampling integration module comprises N sampling units. Each of the sampling units comprises a sampling switch, an output switch and a sampling capacitor. Digital pulses are transmitted in order, so the sampling switches of the sampling units are successively closed. When the sampling switches are closed, input current signals will charge the sampling capacitors in the corresponding positions. Compared with the traditional AD sampling and storing method, requirements on power consumption of a system and operation speed of a processor are greatly reduced; and quite far acting distance and quite high distance measuring precision can be achieved via quite small size of the system and quite low power consumption.

An apparatus for optical body analysis is built with an illumination and detection head, and an optical coupler. The illumination and detection head comprises a light source for illuminating a body portion to analyze through the optical coupler and a detector for receiving light diffusely reflected by the body portion. The optical coupler is mechanically decoupled from the illumination and detection head and is adapted to be in contact with an outer surface of the body portion while the contact between the optical coupler and the body portion minimally affects physical properties of the body portion. The apparatus may further comprise a position unit adapted to adjust the position of the illumination and detection head relative to the optical coupler so that the detector receives through the optical coupler light generated by the light source and diffusely reflected by the body portion.

The invention discloses a micro-channel fast neutron flight time detector which comprises a neutron absorber and an electron collector arranged at one side of the neutron absorber, a plurality of channels are distributed in the neutron absorber in an array mode, secondary electron emission layers are arranged on the inner walls of the channels, and each channel penetrates through the thickness direction of the neutron absorber. The neutron absorber is provided with electrodes on the side surfaces corresponding to the two ends of the channel respectively, a time gating pulse high voltage is loaded between the two electrodes and used for forming an electric field in the channel, and the direction of the electric field faces the electron collector. The detector has the advantages that signalsof the neutron time-of-flight spectrum can be gated in the time domain, and the measurement signal-to-noise ratio of weak signals under strong interference is higher.

A multicarrier non-linear clipping distortion compressed sensing estimation method of relieving the observation interference, provided by the present invention, comprises the following steps of S1 before the target information is measured, pre-configuring a channel observation interference inhibition module; S2 before the target information is measured, using the channel observation interference inhibition module to pre-estimate an observation interference component, denoising a reception end original frequency domain symbol, and constructing an alternative observation vector; S3 during a target information measurement process, generating a corresponding row step measurement matrix according to the observation interference component estimation information, a measurement compression ratio and a measurement criterion, and acquiring data in a plurality of sub-channels as the final observation vector information. The method of the present invention still shows a strong communication performance on the conditions of the low measurement compression ratio and the depth clipping, and enables the system robustness to be improved.

The invention discloses a mobile multifunctional grounding device testing system, which includes a control module and a voltage regulating module connected to the control module, a DC module and an AC module; in the working state, the system can be injected into the grounding network according to the needs of the test work. Power frequency current signal or DC current signal, strong anti-interference ability, high measurement accuracy, and high current test, can realize complex geological structure areas such as uniform and uneven soil resistivity, grounding resistance, surface potential gradient, contact potential difference, Accurate testing of grounding parameters such as step voltage difference. The advantages of the present invention are: the generated large power frequency current has a higher measurement signal-to-noise ratio, and the current-carrying depth of the ground surface is deeper, which is closer to the actual system short-circuit current flowing into the ground network; it can generate hundreds of amperes DC large current, has a high measurement signal-to-noise ratio for stray current in the ground.