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626 results about "Single measurement" patented technology

Method and apparatus to achieve a process, temperature and divider modulus independent PLL loop bandwidth and damping factor using open-loop calibration techniques

Several open-loop calibration techniques for phase-locked-loop circuits (PLL) that provide a process, temperature and divider modulus independence for the loop bandwidth and damping factor are disclosed. Two categories of open-loop techniques are presented. The first method uses only a single measurement of the output frequency from the oscillator and adjusts a single PLL loop element that performs a simultaneous calibration of both the loop bandwidth and damping factor. The output frequency is measured for a given value of the oscillator control signal and the charge-pump current is adjusted such that it cancels the process variation of the oscillator gain. The second method uses two separate and orthogonal calibration steps, both of them based on the measurement of the output frequency from the oscillator when a known excitation is applied to the open loop signal path. In the first step the loop bandwidth is calibrated by adjusting the charge-pump current based on the measurement of the forward path gain when applying a constant phase shift between the two clocks that go to the phase frequency detector, while the integral path is hold to a constant value. During the second step the damping factor is calibrated by adjusting the value of the integral loop filter capacitor based on the measurement of the oscillator output frequency when excited with a voltage proportional with the integral capacitor value, while the proportional control component is zeroed-out.
Owner:SILICON LAB INC

LED optical parameter comprehensive testing device

The invention discloses an LED optical parameter comprehensive testing device, belonging to the technical field of optical parameter measurement. The LED optical parameter comprehensive testing device is technically characterized in that one end of a horizontal base provided with a one-dimensional mobile platform is fixedly provided with an arc-shaped clamp provided with a fiber-optic probe and astandard luminosity probe, the other end of the horizontal base is fixedly provided with an arc-shaped light collector consisting of an arc fiber-optic array and a linear array CCD (Charge Coupled Device), and a rotary clamping table for holding an LED to be tested is arranged on the one-dimensional mobile platform; light information acquired by the fiber-optic probe is converted into a spectrum band by a spectrograph and then is sent into a computer, outputs of the standard luminosity probe and the linear array CCD are sent to the computer through the data acquisition unit, the computer performs corresponding processing and operation on measurement data through measurement software to finally obtain the luminescence characteristics of the LED to be tested. According to the invention, theproblem on comprehensively measuring the LED on a single measurement instrument is solved; and the LED optical parameter comprehensive testing device has the characteristics of simplicity for operation, compact structure, fastness for measurement, easiness for realization and the like.
Owner:CHINA NORTH IND NO 205 RES INST

Piezoelectric sensor for measuring pressure fluctuations

The invention relates to a piezoelectric sensor for the improved measurement of mechanical variables such as force, pressure or measurement variables which are derived there from, particularly a PVDF film sensor having an improved sensitivity and temperature stability of the measurement signal for pressure measurements that vary in time and/or space, and for the one- and two-dimensional determination of the position and propagation velocity of pressure fluctuations and pressure waves with a single measurement sensor at a measurement location. A preferred field of application of the invention is the non-invasive, low strain and continuous measurement of the pulse rate and the systolic and diastolic blood pressure of humans and animals by determining the velocity and the signal form of the pulse waves. The object of the invention is to allow the measurements of the blood pressure and the pulse rate, for example even in the case of emergency patients having only a very low blood pressure and patients having circulatory disorders in the extremities, for example patients which have developed diabetes or the “smoker's leg”, by using only one sensor at a measurement location due to the improved measurement sensitivity of the piezoelectric sensor, with the result that the continuous application of a pressurized jacket for continuously measuring and monitoring the blood pressure is not necessary. The present invention solves this problem in that a plurality of parallel strips of a piezoelectric material (1) are associated as a measurement membrane in the pressure sensor according to the invention with a sensor base body (4) in such a manner that the parallel strips are tension preloaded in a one-dimensional and elastic manner in the direction of the piezo dipole orientation and that an empty cavity (5) is provided between the tension preloaded piezoelectric sensor material (1) in the measurement portion and the sensor base body (4), formed by a recess/cutout.
Owner:SECTORCON ING FUR SYST UND SOFTWARETECHN MBH

Large-component three-dimensional measurement method based on line structured light and industrial robot

The invention discloses a large-component three-dimensional measurement method based on line structured light and an industrial robot, and the method consists of two parts: three-dimensional data acquisition of single measurement and three-dimensional data splicing between multiple measurements. According to the invention, the line structured light three-dimensional measurement technology and therobot hand-eye calibration technology are combined, the line structured light three-dimensional measurement system is used for obtaining three-dimensional data of single measurement, and robot hand-eye calibration realizes three-dimensional data splicing among multiple measurements. According to the method for calibrating the monocular line structured light plane under the assistance of the binocular camera, the line calibration process is simplified, and the line reconstruction precision is improved; a spatial circle fitting method is adopted to fit the sphere center coordinates of the standard sphere, so that the light plane can be any plane equation, the application range of the standard sphere hand-eye calibration method is expanded, and the measurement method can accurately reconstruct a target three-dimensional point cloud model.
Owner:NANJING UNIV OF SCI & TECH

Sound field separating method based on single-surface measurement and local acoustical holography method

The invention relates to the field of noise, in particular to a sound field separation and reconstruction method applicable to sound field separation and reconstruction of large sound sources. The sound field separation and reconstruction method comprises the following steps of: acquiring sound pressure and normal particle vibration velocity on a measuring surface; performing zero filling extension on the measuring surface positioned between two sound sources; acquiring transfer matrixes between the extended measuring surface and surfaces of the two sound sources, namely sound source faces; building a transitive relation between the sound pressure and the normal particle vibration velocity on the measuring surface; and acquiring the sound pressure and the normal particle vibration velocity of the first sound source face and the sound pressure and the normal particle vibration velocity of the second sound source face. A sound field is separated and reconstructed by using the single-measurement-surface and local near-field acoustical holography method. The sound field separation and reconstruction method has the characteristics of simplicity, short calculation time and high calculation efficiency, and can be widely applied to the measurement of near-field acoustical holography, the measurement of material reflecting coefficients, the separation of scattering sound fields and the like of large-size sound-source sound fields.
Owner:三亚哈尔滨工程大学南海创新发展基地

A soil profile moisture measuring device and its measuring method

The invention discloses a soil profile moisture measuring device and a measuring method thereof. The device includes a host computer (1), a sensor node (2), an insulating sleeve (6), a sealed top cover (5) and a waterproof plug (7); the host computer (1) passes through a data acquisition and processing module (3 ) is connected to the sensor node (2); the insulating sleeve (6) is installed outside the sensor node (2), and the lower end of the insulating sleeve (6) is connected to the waterproof plug (7), the The upper end of the insulating sleeve (6) is connected to the sealing top cover (5) through the connecting body (8); the sensor node (2) includes two metal sheets (15), and the two metal sheets (15) are radially connected to each other The intervals are fixed on the surface of the insulating cylinder (12), and the two metal sheets (15) are respectively connected with the sensor circuit board (16). The method can adjust the number and spacing of the sensor nodes (2), set the address codes of each sensor node (2) of the device through the host computer (1), measure and store and display the results. The device has simple structure, easy layout, convenient use, and can be disassembled and assembled freely to realize the measurement of single-point or multi-point dynamic water content of the soil profile; the method is flexible and convenient, and realizes the dynamic measurement of soil at different depths.
Owner:JIANGSU UNIV

Method for nondestructive evaluation of residual stress levels in aluminum alloy forged piece through ultrasonic waves

The invention belongs to the field of nondestructive detection and relates to a method for nondestructive evaluation of residual stress levels in an aluminum alloy forged piece through ultrasonic waves. According to the method, the phenomenon that the propagation speed of the ultrasonic waves in materials can be affected by stress in the materials to a certain extent is used, and the difference of residual stress levels among different positions in the large size aluminum alloy forged piece is reflected through changes of sound speeds. The method has the advantages of being high in detection speed, large in measuring depth, good in economy and the like. The residual stress in the large size aluminum alloy forged piece is measured through the sound elastic effect of the ultrasonic waves in the method, and the method has the advantages of being high in measuring speed, convenient to use, flexible in measuring range, good in economy and the like. The single-time measuring time of the method is about five minutes and is shorter that the single-time measuring time of a neutron diffraction residual stress measuring method, the detection speed is high, the maximum measuring depth of the method can reach 400 mm, is larger that the measuring depth of the neutron diffraction method, and is much larger that the measuring depth of an X-ray method or a Barkhausen noise method.
Owner:AVIC BEIJING INST OF AERONAUTICAL MATERIALS
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