93results about How to "Wide frequency response" patented technology

The invention relates to the technical field of radar, in particular to a millimeter-wave quasi-optical integrated dielectric lens antenna and an array thereof. The array consists of a microstrip integrated antenna, a dielectric lens, an objective lens, an array base, a reflecting mirror, a protective cover and a beam transfer switch; one end face of the dielectric lens is a hemisphere or an ellipsoid, while the other end face is a cylindrical section; the microstrip integrated antenna is generated by an dielectric substrate, the front surface of the dielectric substrate is closely adhered tothe cylindrical section of the dielectric lens and serves as a feed source, and the back surface is grounded; the hemispherical or ellipsoidal end face of the dielectric lens is an antenna radiating surface; the length of the cylindrical part of the dielectric lens can be changed; the antenna array is arranged into a linear array or an area array; the array base and the reflecting mirror have conical quasi-optical reflecting mirror surfaces; the focus of the objective lens of the linear array or the area array aligns with the central line of the dielectric lens; the protective cover is arranged outside; and the antenna array is controlled by the beam transfer switch. The antenna structure has strong shock resistance and dust prevention, and is suitable for millimeter-wave radars for planes, automobiles and ships, and receiving / emitting sensing of communication equipment.

The invention relates to the technical field of radar, in particular to a millimeter-wave quasi-optical integrated dielectric lens antenna and an array thereof. The array consists of a microstrip integrated antenna, a dielectric lens, an objective lens, an array base, a reflecting mirror, a protective cover and a beam transfer switch; one end face of the dielectric lens is a hemisphere or an ellipsoid, while the other end face is a cylindrical section; the microstrip integrated antenna is generated by an dielectric substrate, the front surface of the dielectric substrate is closely adhered tothe cylindrical section of the dielectric lens and serves as a feed source, and the back surface is grounded; the hemispherical or ellipsoidal end face of the dielectric lens is an antenna radiating surface; the length of the cylindrical part of the dielectric lens can be changed; the antenna array is arranged into a linear array or an area array; the array base and the reflecting mirror have conical quasi-optical reflecting mirror surfaces; the focus of the objective lens of the linear array or the area array aligns with the central line of the dielectric lens; the protective cover is arranged outside; and the antenna array is controlled by the beam transfer switch. The antenna structure has strong shock resistance and dust prevention, and is suitable for millimeter-wave radars for planes, automobiles and ships, and receiving / emitting sensing of communication equipment.

An apparatus and method of detecting COPD and in particular, emphysema utilizes a change in acoustic transmission characteristics of a lung due to e.g. the appearance of fenestrae (perforations) in the alveoli of the lung. The use of acoustic signals may provide good sensitivity to the existence of alveolar fenestrae, even for microscopic emphysema, and the appearance and increase in fenestrae may be determined by monitoring acoustic transmission characteristics such as, for example, an increase in acoustic signal velocity and velocity dispersion, and / or a change in attenuation. A transmitter may be located in e.g. the supra-clavicular space and receivers may be mounted on the chest. Measurements may be correlated between pairs of receivers to determine acoustic transmission profiles.

The invention features a miniature, second-order, microcrystalline silicon microphone diaphragm formed using silicon microfabrication techniques. The diaphragm is composed of two or more rigid diaphragm elements hinged to one another providing second- or higher-order response depending on the number of diaphragm elements used. The response of the differential diaphragm has a response that is highly dependent on the direction of the incident sound. The diaphragms are useful for constructing highly innovative microphones that have far greater directionality, better sensitivity, wider frequency response, and lower noise than is achievable with current technology.

A voltage sensor is described that consists of a plurality of identical series-connected sections, where each section is comprised of an arrangement of impedance elements. The sensor is optimized to provide an output ratio that is substantially immune to changes in voltage, temperature variations or aging. The voltage sensor can be scaled to various voltage levels by varying the number of series-connected sections.

The invention provides a production method of a high-power precision alloy SMD (surface mount device) resistor. The production method comprises the steps: respectively combining two oxygen-free copper strips with two sides of a resistor alloy strip to form an integrated strip-shaped resistor strip, and wrapping a high-heat-conductivity substrate with the integrated strip-shaped resistor strip; etching a basic resistor structure on a wrapping body; precisely adjusting the resistance value of the basic resistance structure; coating, terminal electroplating and printing a resistor body to form a high-power precision alloy SMD resistor. The material with high heat radiation capability and high heat conductivity such as a metal substrate, a high-heat-conductivity ceramic substrate is used as the substrate, so that the actual load capacity of the resistor is greatly increased; the oxygen-free copper strip is partially arranged on the side surface and below the substrate and used as an electrode lead, so that the contact area is increased, and the heat conductivity of the resistor body is also increased on the other hand.

Methods and systems utilizing seismic sensors configured or designed for use in seismic signal detection. An electrical current is applied to a seismic sensor such that the moving coil is located at a neutral position relative to the magnetic field in the seismic sensor to compensate for gravitational acceleration.

The invention relates to a giant magnetoresistive effect current sensor using an amorphous alloy magnetic ring structure, and belongs to the technical field of power system measurement. In the current sensor, a wire to be measured passes through an amorphous alloy magnetic ring; and a direct current magnetic biasing coil is wound on the amorphous alloy magnetic ring and is powered by a direct current constant current source. A plurality of layers of giant magnetoresistive effect chips are arranged in an air gap of the amorphous alloy magnetic ring. Positive output ends and negative output ends of the chips are connected with the in-phase input end and the inverted input end of an instrument amplifier respectively; and an output end of the instrument amplifier is connected with an in-phase input end of an operational amplifier. A voltage following resistor is connected in parallel between an inverted input end and an output end of the operational amplifier; the output end of the operational amplifier is connected with an input end of an analog / digital converter; and an output end of the analog / digital converter is connected with a nixie tube display. The current sensor has the advantages of small size, low cost, low energy consumption, wide frequency response, high sensitivity, stabile characteristic and the like, and meets the requirements of environmental friendliness, energy conservation and large-scale distributed monitoring in a novel intelligent power grid.

The invention discloses a surface electromyographic electrode comprising a signal acquisition unit and having an amplifying function. After the acquisition unit acquires an electromyographic signal, the electromyographic signal is processed by a signal filter unit and a signal amplifying unit in turn, and an expected electromyographic signal is output from a signal output unit; the acquisition unit comprises a signal electrode, a grounding electrode and a reference electrode; the signal filter unit comprises a high-pass filter circuit; and the signal amplifying unit comprises an instrument amplifier. The electromyographic electrode has good anti-jamming capability, can accurately acquire the electromyographic signal, and can well meet the requirements of research and application on the aspect of clinical medicine.

The invention relates to an optic fiber type voltage measuring method used in an electric-power grid system for measuring various transient voltages, and a device thereof. The measurement method comprises the steps: a metal induction polar plate is placed on the surface of a measured high-voltage conductor; capacitances formed by the induction polar plate respectively with the measured high-voltage conductor and the ground are utilized for forming a capacitive voltage divider; after the voltage dividing ratio of the capacitive voltage divider and the voltage value on the capacitance between the induction polar plate and the measured high-voltage conductor are measured, the voltage value to ground of the measured high-voltage conductor is acquired by conversion. The measuring device consists of a front end processor externally provided with the metal induction polar plate, an optic fiber, a photoelectric converting module and a computer part, wherein, the induction polar plate and a shielding case of the front end processor form a capacitance type voltage sensor. Compared with the prior art, the invention adopts the method that the capacitance type voltage sensor directly measures the field strength of an electrified body surface to measure the voltage, thus having the advantages of good measurement property, simple structure and convenient use.

An acoustic device comprising a diaphragm (10) having an area and having an operating frequency range and the diaphragm (10) being such that it has resonant modes in the operating frequency range, an electromechanical transducer having a drive part coupled to the diaphragm (10) and adapted to exchange energy with the diaphragm, and at least one mechanical impedance means (20,22,24) coupled to or integral with the diaphragm, the positioning and mass of the drive part (26) of the transducer and of the at least one mechanical impedance means (20,22,24) being such that the net transverse modal velocity over the area of the diaphragm (10) tends to zero.A method of making an acoustic device having a diaphragm having an area and having an operating frequency range which includes the piston-to-modal transition, comprising choosing the diaphragm parameters such that it has resonant modes in the operating frequency range, coupling a drive part of an electro-mechanical transducer to the diaphragm to exchange energy with the diaphragm, adding at least one mechanical impedance means to the diaphragm, and selecting the positioning and mass of the drive part of the transducer and the positioning and parameters of the at least one mechanical impedance means so that the net transverse modal velocity over the area tends to zero.

The invention discloses an eddy probe array for detecting pipeline deformation, and belongs to the technical field of pipeline non-destructive testing. An eddy distance measurement principle is applied to detection on large deformation of pipelines such as pipeline expansion and concaveness. A whole eddy distance measurement probe sensor comprises functional modules of an excitation circuit, a coil, a signal receiving and regulating module and a data acquisition and storage module. A detector with the array type eddy distance measurement probe is adopted to scan inside an oil-gas pipeline, the influence of an alternating magnetic field sensed by the probe on a pipeline wall to equivalent impedance of the excitation coil is converted into variation of voltage and current signals, by virtue of the variation of the electric signals, the variation of the vertical distance D of the eddy probe from the pipeline is measured, and thus geometrical parameters of pipeline expansion and concaves can be obtained. By adopting the eddy probe array, non-contact type continuous measurement on damage such as pipeline expansion and concaveness can be achieved, circumferential full-coverage detection of the probe can be achieved, and the eddy probe array has the characteristics that relatively large expansion can be measured, the sensitivity is high, the frequency response is wide, detection omission can be prevented to the maximum extent, and the like.

A new type of circuit for driving an electromagnetic acoustic transducer (EMAT) which does not employ push-pull technology using a transformer but instant uses a novel circuit employing a series of Mosfet switches to correct all the disadvantages of using a transformer.

Electronic circuitry for high-power, high-frequency excitation of electromagnetic acoustic transducers (EMAT) without the use of a matching transformer is described. This circuit contains a least 4 switching devices such as power Mosfet transistors, arranged in an H-Bridge configuration that are designed to drive various EMATs over a wide range of frequencies. The switching devices can be connected in parallel with respect to the H-Bridge and switched in sequence for greater power output and variety of wave forms. This circuit configuration can provide a many excitation waveforms including, Churp, Hemming window tone burst, rectangular tone burst and Barker Code wave forms.An improved electronic pulser circuit based on the H-bridge topology is designed for driving the sensor coils of an electromagnetic acoustic transducer (EMAT) to correct the disadvantages of conventional H-bridge pulsers and pulsers that require the use of an output transformer. A plurality of switching devices, primarily power Mosfets, are connected in parallel and augmented with support circuitry to provide improved performance in terms of increased power output, stability, reduced noise and complex output wave forms. This improved design provides for the application of modulated pulses such as multi-pulse, multi-frequency tone bursts of peak power outputs in excess of 20 thousand watts and frequencies in excess of 10 thousand Hertz.

An acoustic device comprising a diaphragm (10) having an area and having an operating frequency range and the diaphragm (10) being such that it has resonant modes in the operating frequency range, an electromechanical transducer having a drive part coupled to the diaphragm (10) and adapted to exchange energy with the diaphragm, and at least one mechanical impedance means (20,22,24) coupled to or integral with the diaphragm, the positioning and mass of the drive part (26) of the transducer and of the at least one mechanical impedance means (20,22,24) being such that the net transverse modal velocity over the area of the diaphragm (10) tends to zero. A method of making an acoustic device having a diaphragm having an area and having an operating frequency range which includes the piston-to-modal transition, comprising choosing the diaphragm parameters such that it has resonant modes in the operating frequency range, coupling a drive part of an electro-mechanical transducer to the diaphragm to exchange energy with the diaphragm, adding at least one mechanical impedance means to the diaphragm, and selecting the positioning and mass of the drive part of the transducer and the positioning and parameters of the at least one mechanical impedance means so that the net transverse modal velocity over the area tends to zero.

An MR system features an intracavity probe and associated interface device. The probe includes a shaft, a balloon at one end thereof, and a coil loop within the balloon. The loop has two drive capacitors and a tuning capacitor, all of which in series. A junction node between the drive capacitors serves as a ground for electrically balancing the loop. Diametrically opposite the node, the tuning capacitor enables the loop to resonate at the operating frequency of the MR system. The interface allows the MR system to couple the loop to a port of the MR system during a receive cycle thereof and decouple it from the port during a transmit cycle thereof. With its balloon inserted and inflated within a cavity of a patient, the probe allows the MR system to generate images and / or spectra of the region of interest using the MR signals received by the loop.

A high fidelity, low-profile loudspeaker assembly includes an enclosure having a rear panel which is highly thermally conductive. At least one speaker driver is mounted in the enclosure, the driver including a forwardly facing diaphragm driven by a voice coil former carrying a voice coil, and a rearwardly extending motor structure. An aperture is provided in the rear panel to receiving the driver's motor structure, and a thermally conductive gasket seals the rear panel aperture around cup to provide a thermal path from the driver motor to the rear panel for cooling the driver. On one driver embodiment, a generally dome-shaped annular spider surrounds and supports the voice coil former, the spider being connected at its inner periphery to the approximate vertical midpoint of the voice coil former.

A transmission system of expandable electronic device includes a first electronic device and a second electronic device. The first electronic device includes a first socket unit and a first processor, and the first socket includes a hall sensing circuit. The second electronic device includes a first plug unit and a second processor, and the first plug unit includes a first magnetic unit. The first processor couples to the first hall sensing circuit, the second processor couples to the first plug unit. By the plug unit inserts the first socket unit, the second electronic device couples to the first electronic device. When the first plug unit inserts the first socket unit, the first hall sensing circuit senses the first magnetic unit to generate a magnetic field sensing signal, and the first processor executes a first processing procedure according to magnetic field sensing signal.

The invention discloses an optical current sensor based on the Faraday magneto-optic effect. The optical current sensor comprises a laser generator which is used to generate polarized laser of a set wavelength, an integrated probe which comprises a magneto-optical medium, a photodetector which is used to convert an optical signal into an electrical signal, and a data analyzing and processing device which filters out noise through the combination of hardware filtering and software filtering to acquire a good response effect. A polarizer and an analyzer are arranged on two ends of the magneto-optical medium respectively, and are insulatedly packaged on both ends of the magneto-optical medium respectively. The laser generator and the polarizer are connected through an optical fiber path, andthe photodetector and the analyzer are connected through an optical fiber path. The invention further discloses a current measurement method of the optical current sensor based on the Faraday magneto-optic effect.

A voltage sensor is described that consists of a plurality of identical series-connected sections, where each section is comprised of an arrangement of impedance elements. The sensor is optimized to provide an output ratio that is substantially immune to changes in voltage, temperature variations or aging. The voltage sensor can be scaled to various voltage levels by varying the number of series-connected sections.

A high fidelity, low-profile loudspeaker assembly includes an enclosure having a rear panel which is highly thermally conductive. At least one speaker driver is mounted in the enclosure, the driver including a forwardly facing diaphragm driven by a voice coil former carrying a voice coil, and a rearwardly extending motor structure. An aperture is provided in the rear panel to receiving the driver's motor structure, and a thermally conductive gasket seals the rear panel aperture around cup to provide a thermal path from the driver motor to the rear panel for cooling the driver. On one driver embodiment, a generally dome-shaped annular spider surrounds and supports the voice coil former, the spider being connected at its inner periphery to the approximate vertical midpoint of the voice coil former.

An acoustic device comprising a diaphragm (10) having an area and having an operating frequency range and the diaphragm (10) being such that it has resonant modes in the operating frequency range, an electro-mechanical transducer having a drive part coupled to the diaphragm (10) and adapted to exchange energy with the diaphragm, and at least one mechanical impedance means (20,22,24) coupled to or integral with the diaphragm, the positioning and mass of the drive part (26) of the transducer and of the at least one mechanical impedance means (20,22,24) being such that the net transverse modal velocity over the area of the diaphragm (10) tends to zero.A method of making an acoustic device having a diaphragm having an area and having an operating frequency range which includes the piston-to-modal transition, comprising choosing the diaphragm parameters such that it has resonant modes in the operating frequency range, coupling a drive part of an electro-mechanical transducer to the diaphragm to exchange energy with the diaphragm, adding at least one mechanical impedance means to the diaphragm, and selecting the positioning and mass of the drive part of the transducer and the positioning and parameters of the at least one mechanical impedance means so that the net transverse modal velocity over the area tends to zero.

The invention discloses a method and a device for testing the parameters of a metal pipe fitting with electric eddy under the eccentric state of a probe; and the device mainly comprises a signal generator, a power amplifier, an electric eddy probe, a signal conditioning circuit, an acquisition card and a computer data processing system. The device outputs sine wave with the signal generator, and the sine wave is amplified by the power amplifier and drives the electric eddy probe. A signal output by the electric eddy probe enters the computer data processing system after being conditioned by the signal conditioning circuit and acquired by the acquisition card. The computer data processing system preprocesses the acquired signal and sets an initial parameter value to be tested; the simulation result of a probe impedance theory model is compared with an experimental result; an estimated metal pipe fitting parameter is optimized again and again according to the deviation of the simulation result and the experimental result, until the deviation meets relevant requirements; and a final estimated parameter value is output and displayed as a test result. According to the method and the device, no coupler or precise centering device is needed, and a plurality of parameters of the metal pipe fitting can be precisely measured on line under the eccentric state of the probe.

The invention discloses a shear stress sensor based on 1-3 type cement-based piezoelectric composites and a preparation method thereof. The shear stress sensor comprises a 1-3 type cement-based piezoelectric composite component; and a packaging layer and a shielding layer with which the 1-3 type cement-based piezoelectric composite component is wrapped in sequence. Positive and negative electrodesof the 1-3 type cement-based piezoelectric composite component are led out of the shielding layer through a wire to be connected with a shielding wire. The shielding wire is connected with the shielding layer. The component comprises a cement-based piezoelectric composite body and an electrode. The cement-based piezoelectric composite body is composed of a piezoelectric ceramic column array formed by piezoelectric ceramic columns and a cement base material filled among the piezoelectric ceramic columns. The piezoelectric ceramic column array is obtained by cutting a polarized piezoelectric ceramic block with the cutting direction perpendicular to the polarization direction of the piezoelectric ceramic block. The sensor of the invention has the advantages of high sensitivity, wide frequency response, good anti-interference effect and good compatibility with a concrete structure, and can be used for the health monitoring of the concrete structure.

The invention relates to a non-contact phase-difference type torque sensor which comprises an input sleeve, an output sleeve, a Hall sensor, a first involute gear and a second involute gear, wherein the input sleeve is connected with the output sleeve through a torsion bar, a hub bore of the first involute gear is in interference fit with the output sleeve, a hub bore of the second involute gear is in interference fit with the input sleeve, third sections of shaft segments of the input sleeve and the output sleeve are respectively matched with an inner ring of a corresponding bearing, an outer ring of the bearing is respectively matched with two groups of sensor shells which are arranged at two sides of the torsion bar, a magnetic circuit support is respectively fixed on the inner surface of each sensor shell, a magnetic circuit assembly and a circuit board are fixed on each magnetic circuit support, the Hall sensor is welded on the circuit board, and a detection surface of the Hall sensor is arranged in an air gap where the end surface of magnetic-conducting soft iron a just faces to a top addendum circle of the involute gear. The invention has the advantages of simple structure, accurate test, good stability, comparatively lower cost, and the like.

Methods and systems utilizing seismic sensors configured or designed for use in seismic signal detection. An electrical current is applied to a seismic sensor such that the moving coil is located at a neutral position relative to the magnetic field in the seismic sensor to compensate for gravitational acceleration.

The invention provides non-contact measurement equipment and method of contact net voltage. The equipment comprises a non-contact electric field coupling sensor and a data acquisition and analysis device, wherein the non-contact electric field coupling sensor comprises vehicle top high voltage equipment and which is arranged on electrical locomotive high voltage equipment or a contact net detection vehicle and an electric field distribution uniform area which is arranged around a contact net line, and the non-contact electric field coupling sensor is used for conducting coupling sensing on anelectric field strength signal in the electric field distribution uniform area; the data acquisition and analysis device is connected with the non-contact electric field coupling sensor and is used for receiving the electric field strength signal subjected to coupling sensing by the non-contact electrical field coupling sensor, and determining the contact net voltage according to the electric field strength signal and the relation of the electric field strength signal and voltage. By means of the non-contact measurement equipment and method of the contact net voltage, the efficiency, safety and convenience of detection and maintenance of the contact net voltage are improved.