261results about How to "Good signal to noise ratio" patented technology

An exemplary system and method for detecting at least one analyte in a sample comprises inter alia a source of radiation (300), a near-field aperture array (315), a chromatographic field (330), a detector (350), and a data processor (370). Disclosed features and specifications may be variously controlled, adapted or otherwise optionally modified to improve detection of any sub-diffraction-limited scale phenomena. Exemplary embodiments of the present invention representatively provide for improved S/N, increased sample throughput, refined spectral resolution and enhanced detection sensitivity.

The invention discloses a reflective all-optical fiber current sensor, which is characterized in that a sagnac interference system which consists of a polarization maintaining optical fiber coupler adopts two 1/4 wave plates and a Faraday rotator as the phase bias of light waves and adopts a single polarization maintaining optical cable as a transmission line and the reflective end surface of an optical fiber sensing ring to commonly form the reflective sensing system. An interference optical circuit further adopts a polarization multiplexer, one port thereof is welded by 90 degrees, and two polarizers are additionally added at the port of the polarization maintaining optical fiber coupler, thereby eliminating the polarization noise of a plurality of devices during the polarization transformation and the transmission. The reflective all-optical fiber current sensor with the optical circuit structure has stable light wave phase bias. Interference signals have very high signal-to-noise ratio. The circuit processed by electric signals is greatly simplified. Therefore, the phase delay generated by the circuit which is processed by the electric signals is very small. The angular difference of an actual electronic current transformer which is composed by the reflective all-optical fiber current sensor can achieve the national 0.1 level standard.

Radio frequency transmission systems often suffer from the problem of co-site interference, where the frequency band of a strong radio transmitter overlaps with the frequency band of a co-located and/or remote radio receiver, such that the transmitter interferes with the ability of the receiver to detect a weak signal of interest. There is a need for a device that can process both the transmitted radio signal and the received radio signal to eliminate such interference. Previous attempts to solve this problem have been unable to cancel in-band interference in excess of 20 to 40 dB stronger than the signal of interest over a broad bandwidth, with large dynamic range, and with a high degree of linearity. Disclosed is a robust system and method for cancelling broadband in-band RF interference that operates in a dynamically changing multipath environment.

The invention discloses a method for estimating the signal-to-noise ratio of time-frequency overlapped signals in cognitive radio. The method includes the following steps that: a normalized higher-order cumulant equation is constructed according to the normalized higher-order cumulant of received signals; all component signal modulation type combinations are traversed, the power of component signals is calculated through the normalized higher-order cumulant equation, and whether the modulation type combinations are correct is judged; and correct component signal modulation type combinations and power are obtained, the noise power of the time-frequency overlapped signals is calculated, so that the signal-to-noise ratio of the time-frequency overlapped signals in the underlay cognitive radio can be estimated. According to method, the normalized mean square error of the estimation of the signal-to-noise ratio is smaller than 0.2 under a high spectrum overlap rate when a signal-to-noise ratio is 0dB. The method has excellent performance in the estimation of the signal-to-noise ratio of the time-frequency overlapped signals in the underlay cognitive radio. With the method of the invention adopted, the measurement of interference temperature can be facilitated, primary users and secondary users can coexist under the interference temperature, and therefore, spectrum efficiency can be improved.

The invention is applicable to the terahertz optical field, and provides an electro-optic sampling device used for measuring terahertz optical pulse and a measuring method thereof. The device comprises a polarizer, an electro-optic sampling crystal, a beam splitter, a first phase compensator, a second phase compensator, a first analyzer, a second analyzer and a balanced detector. In the device, the detection light modulated by the terahertz optical pulse is divided into two paths, one of which passes through the first phase compensator and the first analyzer and is received by a first receiver, and the other one passes through the second phase compensator and the second analyzer and is received by a second receiver; therefore, the two beams of optical pulse introduced into the balanced detector have the similar noise characteristic, so as to be beneficial to eliminating background noise. Furthermore, the first phase compensator is regulated to lead one path of light to work at the position with the best optical modulation degree, and the second phase compensator is regulated to lead the static birefringence phase values of the two paths of light to be opposite numbers, so that the linear working range is not affected by static birefringence phase, and the signal to noise ratio can be optimized.

The invention relates to an integrated surface acoustic wave (SAW) wireless temperature sensor, comprising an interdigital transducer with an EWC/SPUDT structure and 11 reflectors with short-circuit gate structures, which are manufactured on a piezoelectric substrate, wherein, the EWC/SPUDT receives an electromagnetic wave signal transmitted from a wireless reading unit by a wireless antenna and transforms the signal into surface acoustic wave which is propagated along the reflectors on the surface of the piezoelectric substrate and is respectively reflected by the reflectors, the reflected acoustic wave is retransformed into the electromagnetic wave signal by an EWC/SPUDT2, the signal is returned to the wireless reading unit by the wireless antenna, and finally temperature detection is realized by evaluation on a phase change of time-domain response via a signal processing method. In the sensor, the 11 reflectors of a SAW reflection delay line are divided into two paths for reducing multiple reflection among the reflectors, wherein, 8 reflectors on one path are used for 8-bit electronic tags, and 3 reflectors on the other path are used for temperature detection; and a reflection peak of a time domain S11 with even response is obtained by adjusting electrode number of the reflectors.

The invention provides an image edge detecting method based on Bayer RGB, the method comprises the following steps: providing Bayer RGB images; taking target pixel points as centers, generating matrices of Bayer RGB pixel points in a 3*3 neighborhood, applying detection operators for the gradient operation for various pixel points in the matrices respectively and obtaining gradient amplitudes and gradient angles of various pixel points, and then whether edge points are determined or not through comparing determination of double-threshold values and the gradient of adjacent pixel points. The invention avoids calculating grayness of pixel points, which is suitable for direct edge detection for original images obtained by a CMOS image sensor. The detecting method has the characteristics of good signal to noise ratio, accurate edge positioning and good effect of restraining false edges.

The invention provides a device and a method for measuring a surface defect of a semiconductor material, and belongs to the field of semiconductor tests. The device comprises a sample table, an atomic force microscope conductive probe, a voltage source, a piezoelectric exciting ceramic, an optical microscope system, a monochrometer, a photoelectric detector and a phase lock amplifier, wherein the voltage source and the piezoelectric exciting ceramic are connected with the atomic force microscope conductive probe; and the monochrometer, the photoelectric detector and the phase lock amplifier are connected with one another sequentially. The method comprises the following steps of: putting a sample to be measured on the sample table; making the tip of the probe generate a periodic mechanical vibration; generating periodic light on the exposed surface of the sample to be measured; focusing the light emitted by the sample to be measured on the monochrometer for splitting the light; and measuring a luminous signal. According to the device and the method, the problem that electroluminescent spectra exist during measurement of the surface defect of a semiconductor in the prior art is solved; furthermore, the influence of stray light on a measurement result is avoided; and a high signal to noise ratio.

The invention discloses an intelligent steel cord conveyer belt defect identification method and an intelligent steel cord conveyer belt defect identification system. The identification method includes the following steps: (1) electromagnetic loading; (2) defect signal acquisition; (3) feature extraction; (4) training sample obtainment; (5) class priority determination; (6) multi-class model establishment; (7) multi-class model training; (8) real-time signal acquisition and synchronous class: electromagnetic detection units are adopted for real-time detection, detected signals are synchronously inputted into a data processor, features are extracted and then sent into established multi-class models, and the defect class of a detected conveyer belt is automatically outputted. The identification system comprises an electromagnetic loader, a plurality of electromagnetic detection units, the data processor and an upper computer, the data processor can automatically output the defect class of the detected conveyer belt, and the upper computer bidirectionally communicates with the data processor. The design of the invention is reasonable, the invention is easy to operate and convenient to put into practice, moreover, the using effect is good, the practical value is high, the reliability of conveyer belt defect detection is enhanced, and the efficiency of defect identification is increased.

The invention discloses a method for analyzing a non-conductor material by utilizing a glow discharge mass spectrum, comprising the following concrete steps of: (a), processing the non-conductor material to be analyzed into a strip sample; (b), cleaning and stoving the strip sample; (c), placing metal indium into a silica crucible and heating to a molten state; (d), cladding the surface of the strip sample with a layer of metal indium membrane; (e), cleaning and stoving the strip sample again; and (f), carrying out direct current glow discharge mass spectrum analysis. By utilizing the analysis method provided by the invention, sample grinding and polishing are not needed, the pretreatment is simple and the pollution is avoided; the operation is simple and convenient, the usage amount of the metal indium is greatly decreased and the analysis cost is reduced; the discharge of the sample is similar to that of a conductor sample and is easily stabilized, the stability of a signal is good, the SNR(Signal to Noise Ratio) is ideal, the analysis time is shortened and the analysis efficiency is increased; the method is suitable for the analysis of massive or crystalline materials, the universality is strong and the application range is wide; and the sample has very good discharge stability and analysis repeatability.

The invention discloses a concrete stress sensor by piezoelectric properties of a PVDF (polyvinylidene fluoride) film. The concrete stress sensor comprises an upper sensor shell, a lower sensor shell and the PVDF piezoelectric film, the upper sensor shell and the lower sensor shell are buckled together, the PVDF piezoelectric film is arranged between the upper sensor shell and the lower sensor shell, a nylon sleeve is sleeved on the periphery of the PVDF piezoelectric film, so that the PVDF piezoelectric film is positioned on a boss, insulating layers are respectively arranged on the upper end face and the lower end face of the PVDF piezoelectric film and closely contact with the upper sensor shell and the lower sensor shell, the nylon sleeve and the insulating layers form a sealed insulating space, so that a PVDF piezoelectric film and the sensor shells are separated in an insulating manner, and connection electrodes are respectively arranged on the upper surface and the lower surface of the PVDF piezoelectric film, so that piezoelectric signals are led to the outside of the sensor. The PVDF piezoelectric film is clamped between the two metal shells, a load is transmitted to the PVDF film by the aid of the sensor metal shells, the concrete stress sensor is sensitive in sensing, simple in structure, convenient to package and small in size, and can be embedded into concrete materials to finish an impact stress test.

The invention belongs to the wireless communication signal detection technical field and relates to a block compressive sensing non-orthogonal multiple-address system multiuser detection method. The invention provides a sparseness adaptive detection method which can recombine structured sparseness into block sparseness. According to the block compressive sensing non-orthogonal multiple-address system multiuser detection method of the invention, a block sparseness-adaptive sub-space tracking algorithm is adopted for recombined block sparseness signals; according to the algorithm, a noise power setting threshold is utilized to realize the adaptive evaluation of the sparseness of users, and SER (Symbol Error Rate) performance is improved greatly compared with that of the prior art under a condition that the a priori information of sparseness degree is not required; and a simulation result indicates that the performance of the algorithm can reach an optimal theoretical value after a signal-to-noise ratio is increased to a certain extent.

The invention discloses an ultrasonic flaw detection method of an austenitic stainless steel sheet weld joint. The ultrasonic flaw detection method comprises the following steps of: 1, selecting a phased array ultrasonic flaw detection device; 2, making a reference block by adopting the same material, and determining a material, a shape and a size of the reference block; 3, detecting and debugging the reference block by using the phased array ultrasonic flaw detection device, and screening artificial flaw detection echoes and noise waves; and 4, carrying out sector-scanning on a workpiece by using the phased array ultrasonic flaw detection device, accurately positioning and quantitatively screening doubtful echoes so as to confirm whether the doubtful echoes are flaw echoes. According to the ultrasonic flaw detection method of the austenitic stainless steel sheet weld joint, various flaws in the stainless steel sheet weld joint can be rapidly and effectively detected.

A method for tuning a nuclear magnetic resonance (NMR) tool having an operating frequency and equipped with an antenna, is disclosed comprising: (a) transmitting a rf magnetic field to a sample under investigation; (b) receiving an NMR signal from the sample within a detection window; (c) determining mistuning of said antenna relative to said operating frequency; (d) analyzing the received echo signal to determine mistuning of the received signal from the operating frequency. The mistuning of the received signals from the operating frequency may be determined by analyzing any changes in phase of the echo along the echo signal. The antenna tuning process may be automated by measuring calibrated signal amplitudes at more than one frequency and identifying a maximum amplitude. The system tuning may be maintained by repeating (a) through-(d) while operating the tool and implementing a feedback loop.

The invention relates to the field of molecular biology, and discloses a specific oligonucleotide probe for detection of SNP (single nucleotide polymorphism) sites of CYP2C9 (cytochrome P450 2C9) and (vitamin K epoxide reductase complex subunit 1) VKORC1, and the probe can hybridize with different genotypes of 430th and 1075th site of the CYP2C9 and -1639th site of the VKORC1. The present invention also discloses a specific primer pair for amplification of CYP2C9 and VKORC1 genes in the detection of the SNP (single nucleotide polymorphism) sites, and the primer pair can be used for specific amplification of target areas containing detection target sites in the CYP2C9 and VKORC1 genes. The specific primer pair and the specific probe can complete detection of three SNP site genotypes of the CYP2C9 and VKORC1 by one step, and provides information for people to right use warfarin.

The present invention relates to the technical field of optical fiber measurement and specifically relates to a noise suppression device and a noise suppression method for the distributed polarization crosstalk measurement of an optical polarizer. The noise suppression device for the distributed polarization crosstalk measurement of the optical polarizer comprises a broadband optical source, a polarizer, a first fiber-optic rotary connector, a second fiber-optic rotary connector, a to-be-detected optical fiber device, an optical path correlator, and a polarization crosstalk detecting and signal recording device. According to the technical scheme of the invention, the transmission light and the coupled light are thoroughly separated by means of a polarization beam splitter, so that the noise influence on the interference beat length can be avoided. On the basis of the thermal noise of a control circuit, the transmission light is attenuated by an attenuator, and the coupled light is enabled to be main detecting light. In this way, the shot noise becomes the main noise for limiting the signal noise ratio of the system. Based on the above method, the parameters of the device are adjusted to be appropriate. In this way, on the premise that the dynamic range of the system is kept unchanged, the signal noise ratio of the system is improved by 20 to 40 dB. Therefore, the measurement sensitivity is effectively increased.

The invention discloses a method for estimating the signal-to-noise ratios of component signals of a time-frequency overlap signal in cognitive radio. The method comprises the following steps of estimating the power of each component signal and the power sum of the component signals according to the second-order time-varying moment of a received signal and the second-order time-varying moment of a relevant function; estimating the total noise power in the time-frequency overlap signal according to the power of a received composite signal and the solved power of each component signal; calculating the in-band noise power of each component signal according to the bandwidth of each component signal, and estimating the signal-to-noise ratio of each component signal of the time-frequency overlap signal in an underlay spectrum sharing mode. In the condition of the low signal-to-noise ratios and a high spectrum overlap rate, the method has favorable estimation performance on the signal-to-noise ratios of the component signals of the time-frequency overlap signal. When the overlap rate of the signal is 50 percent and the signal-to-noise ratios are -20dB, the method for estimating the signal-to-noise ratios still has favorable performance.

The invention discloses an infrared optical fiber for detecting sulfur hexafluoride gas and a preparation method thereof. Monocrystalline Si is used as the substrate of the infrared optical filter; Ge is used as a high-index material; and ZnS is used as a low-index material. A main film system surface film and an interference cutoff film system surface film are respectively deposited on two surfaces of the substrate. A film plating process is characterized in that electron beam evaporation of Ge is performed, and the deposition rate is 8 angstroms/sec; porous molybdenum boat electrothermal evaporation of ZnS is performed, and the deposition rate is 20 angstroms/sec; and when evaporation is started, the vacuum degree is 1.0*10<3>Pa and the deposition temperature is 130 DEG C. According to the infrared optical filter for detecting the sulfur hexafluoride gas and a 10560nm bandpass infrared optical filter obtained through the preparation method, a peak transmittance can reach above 90%; a signal-to-noise ratio is greatly improved; an interference by other gases can be well inhibited; and detecting precision and detecting efficiency of an instrument are improved.

The invention relates to a deep ultraviolet APD detection diode based on Ir2O3/Ga2O3 and a manufacturing method thereof. The method comprises the following steps of selecting a beta-Ga2O3 substrate; growing a beta-Ga2O3 material on a beta-Ga2O3 substrate surface to form a homogeneous epitaxial layer; growing an Ir2O3 material on a homogeneous epitaxial layer surface so as to form a heterogeneous epitaxial layer; etching the heterogeneous epitaxial layer and the homogeneous epitaxial layer to form a trapezoidal structure; forming a top electrode on a heterogeneous epitaxial layer surface; and forming a bottom electrode on a lower surface of the beta-Ga2O3 substrate and finally forming an APD detector diode. In the invention, the beta-Ga2O3 material is used, a super high light penetration rate and transparency of the material in a deep ultraviolet area and a visible light area are performed, super high voltage withstanding performance of an APD detector and a high breakdown electric field are ensured; the diode is suitable for extreme environments of a high frequency, high radiation, high temperature and high voltage and the like; under the extreme environments, device reliability can be greatly increased and detection performance is better than that of an existing APD detector.

The invention relates to the microwave photon field, especially to a microwave frequency conversion method and apparatus. The apparatus is composed of a fiber laser, a polarizing beam splitter, an electro-optic modulator, a polarizing controller, a fiber coupler and a photoelectric detector. The fiber laser, the polarizing beam splitter, and the photoelectric detector are successively connected and then are coupled to one input terminal of the fiber coupler; the polarizing beam splitter and the polarizing controller are connected and then are coupled to the other input terminal of the fiber coupler; and the output terminal of the fiber coupler is connected with the photoelectric detector and the photoelectric detector outputs a converted frequency conversion signal. According to the invention, a microwave local oscillator signal source in the traditional frequency conversion way does not need to be provided and conversion from a broadband microwave signal to an intermediate frequency signal can be realized.

The invention provides a composite second-order fractional order signal processing-based edge detection method which belongs to the conventional problem in the mode recognition field. The method is a new algorithm for solving an edge by performing gradient operation on all target pixel points in an image by using fractional order signal processing, and comprises the following steps of: generating a gray level matrix for any image; performing the gradient operation on each pixel point in the matrix by using a detection operator to obtain the gradient amplitude of each pixel point respectively; determining an edge position through an obtained zero-crossing image; and if the gradient amplitude of the target pixel point is greater than a threshold value, determining that the target pixel point is an edge point. By the method, smoothing filter preprocessing of the image is saved and the gradient operation is performed by using a fractional order signal processing-based novel composite derivation algorithm; fractional integral in the algorithm suppresses the interference introduced by a fractional differentiation process; and the method has the characteristics of good signal-to-noise ratio, accurate edge positioning and excellent suppression of false edges. The algorithm can be applied to the fields such as automatic target recognition and the like.

The invention discloses a multi-mode laser-induced breakdown spectroscopy device. The multi-mode laser-induced breakdown spectroscopy device comprises three operating modes which are collineation, reheating and pre-ablation; in the collineation operating mode, an optical path climbing system is arranged on the optical path of a double pulse solid laser, and is used for raising the optical path of 1065nm/532nm coaxially output laser, so as to ensure that laser is focused to the surface of a sample from the part above a sample table to produce plasma; in the reheating and pre-ablation operating modes, first laser of the double pulse solid laser enters the optical path climbing system, and the optical path of the first laser is raised, so that the first laser is focused to the surface of the sample from the part above the sample table to produce plasma; a delay generator controls the triggering timing sequence of the first laser and second laser; the second laser of the double pulse solid laser is directly focused to the plasma; the multi-mode laser-induced breakdown spectroscopy device further comprises a signal gathering and processing system which displays distribution information of elements on the surface of the sample according to characteristic spectral lines emitted by the plasma when the plasma is cooled and space information of the first laser when the first laser beats the sample.

The invention discloses an encapsulation structure of a silicon crystal microphone, which comprises a substrate, an electronic component set, a cover body, an insulated filling body and a conducting layer. The substrate has an upper surface and a lower surface. The electronic component set comprises a silicon crystal microphone arranged on the upper surface of the substrate. The cover is arranged on the upper surface of the substrate and covers the silicon crystal microphone. The insulated filling body is combined on the upper surface of the substrate and the circumference side of the cover body, and provided with a hole communicating with the upper surface of the substrate. In addition, the conducting layer is formed out of the insulated filling body, and the hole of the insulated filling body is provided with a conducting part so as to electrically connect with the substrate.