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133 results about "Reverberation room" patented technology
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A reverberation chamber or room is a room designed to create a diffuse or random incidence sound field (i.e. one with a uniform distribution of acoustic energy and random direction of sound incidence over a short time period). Reverberation chambers tend to be large rooms (the resulting sound field becomes more diffused with increased path length) and have very hard exposed surfaces. The change of impedance (compared to the air) these surfaces present to incident sound is so large that virtually all of the acoustic energy that hits a surface is reflected back into the room. Arranging the room surfaces (including the ceiling) to be non-parallel helps inhibit the formation of standing waves - additional acoustic diffusers are often used to create more reflecting surfaces and further encourage even distribution of any particular sound field.
Reverberating adaptive microwave-stirred exposure system
InactiveUS7105787B2Minimize any discrepancyResistance/reactance/impedenceDielectric heating circuitsFrequency spectrumConstant power
A method and apparatus for adaptively maintaining the power-frequency spectrum in a reverberation chamber. The invention is thus capable of maintaining a relatively constant power-frequency spectrum in the chamber even when a device under examination is placed into the chamber which exhibits selective frequency absorption and or directional frequency absorption. The object disposed within the chamber need not necessarily be a device under examination. Rather, the present invention can also adaptively maintain a relatively constant power-frequency spectrum when heating any material disposed within a electromagnetic wave chamber.
Owner:FIORE INDS
Reverberating adaptive microwave-stirred exposure system
ActiveUS20040134904A1Even magnitudeMinimize any discrepancyResistance/reactance/impedenceDielectric heating circuitsConstant powerFrequency spectrum
A method and apparatus for adaptively maintaining the power-frequency spectrum in a reverberation chamber. The invention is thus capable of maintaining a relatively constant power-frequency spectrum in the chamber even when a device under examination is placed into the chamber which exhibits selective frequency absorption and or directional frequency absorption. The object disposed within the chamber need not necessarily be a device under examination. Rather, the present invention can also adaptively maintain a relatively constant power-frequency spectrum when heating any material disposed within a electromagnetic wave chamber.
Owner:FIORE INDS
Method of using reverberation pool to carry out reciprocity calibration of underwater acoustic transducer
InactiveCN106501795ALower requirementWave based measurement systemsVibration measurement in fluidHydrophoneSound sources
The invention relates to a method of using a reverberation pool to carry out reciprocity calibration of an underwater acoustic transducer. The method of using a reverberation pool to carry out reciprocity calibration of an underwater acoustic transducer includes the steps: 1) according to the lowest frequency to be calibrated for an underwater acoustic transducer to be calibrated, selecting a reverberation pool with the corresponding size; 2) using any one nondirectional sound source and one hydrophone to form an emission / reception energy transducer pair, measuring the output voltage of an open circuit being 1m away from a sound source equivalent sound center in the reverberation pool and recording the emission / reception parameters of the apparatus; and 3) placing the emission / reception energy transducer pair in the reverberation pool, adjusting the same emission / reception parameters, and using a space averaging method to measure the output voltage of the open circuit of the hydrophone. If the method of using a reverberation pool to carry out reciprocity calibration of an underwater acoustic transducer is used to perform calibration of an underwater acoustic transducer, a plurality of hydrophones can be calibrated at the same time, so that the requirement for the experiment pool is reduced. Therefore, even in a reverberation pool with small size or a non anechoic pool, the method of using a reverberation pool to carry out reciprocity calibration of an underwater acoustic transducer can also be used for calibration only when the frequency range for calibration is satisfied.
Owner:HARBIN ENG UNIV
Methods and apparatuses for testing wireless communication to vehicles
InactiveUS20170012714A1Test is expensiveTransmitters monitoringReceivers monitoringAsphaltMulti path
An apparatus for measuring over-the-air (OTA) wireless communication performance in an automotive application of a device under test arranged on or in a vehicle is disclosed. The apparatus comprises a chamber and a platform for supporting the vehicle within the chamber. The platform is a rotatable platform that can rotate the vehicle, and the floor is inwardly reflective, and optionally covered with a top layer to resemble asphalt or other road covers. In one embodiment, the chamber is a reverberation chamber, simulating a multi-path environment, and preferably a rich isotropic multipath (RIMP) environment. In another embodiment, the chamber has inwardly absorbing walls, simulating a random-LOS environment.
Owner:RANLOS AB
Method of testing and evaluating sound insulation property of finished automobile based on reverberation room
InactiveCN103115666AReflects the level of sound insulation performanceSimple test methodVehicle testingSubsonic/sonic/ultrasonic wave measurementMean squareEngineering
The invention provides a method testing and evaluating sound insulation property of a finished automobile based on a reverberation room. Stimulating sound pressure sources are arranged at random multiple positions inside the reverberation room. Sound pressure testers are arranged at multiple positions inside the sealed finished automobile. A sound pressure mean square value outside an automobile body inside the reverberation room is calculated to obtain a stimulating sound pressure. A sound pressure mean square value inside the finished automobile is calculated to obtain a receiving sound pressure. A difference between the stimulating sound pressure and the receiving sound pressure is a sound decay. Thus the sound insulation property of the finished automobile is judged.
Owner:CHONGQING CHANGAN AUTOMOBILE CO LTD
Reverberation chamber
InactiveUS20090303141A1Increase varietyElectromagentic field characteristicsAntennasEngineeringIrradiation
To construct a reverberation chamber, a chamber provided with reflecting walls contains an antenna and a field stirrer which are placed opposite an object to be tested. By modifying an orientation of a main direction of irradiation from the antenna, a very large number of cavity modes are created inside the chamber, achieving the required variety of possible impingements on the object to be tested, such that the test carried out is as conclusive as possible and the least dependent possible on the dimensions and characteristics of the chamber.
Owner:EURON AERONAUTIC DEFENCE & SPACE
Reverberation room platform based method for testing electromagnetic environment effects of electronic system
ActiveCN104407248AAccurately reflect the electromagnetic environment effectEffectively guide the use of securityElectrical testingElectrical field strengthAudio power amplifier
The invention discloses a reverberation room platform based method for testing electromagnetic environment effects of an electronic system. The method is applicable to threshold testing of the electromagnetic environment effects of the electronic system on the basis of a reverberation room platform. The method includes the steps: 1, setting up a test platform; 2, keeping a reside position of a stirrer unchanged, setting a signal source transmitting frequency, increasing amplification factor of a power amplifier until electromagnetic environment effects occur in the electronic system, and recording the current forward input power; 3, changing the reside position of the stirrer, and repeating the step 2; 4, repeating the step 3 to obtain forward input powers corresponding to a plurality of reside positions of the stirrer; 5, taking the minimal forward input power obtained at the step 4 as the input power of a transmitting antenna, enabling the stirrer to rotate by one circle step by step to obtain corresponding electric field strength at each reside position, and taking the maximum value of the electric field strength as the threshold of the electromagnetic environment effects of the electronic system under the signal source transmitting frequency. The reverberation room platform based method has the advantages of procedure simplicity, easiness in implementation and high repeatability of test results.
Owner:PEOPLES LIBERATION ARMY ORDNANCE ENG COLLEGE
Electromagnetic shielding effectiveness testing system under live room condition and testing method thereof
ActiveCN103576028AEasy to calculateGood repeatabilityElectrical testingLiving roomElectromagnetic shielding
The invention discloses an electromagnetic shielding effectiveness testing system under a live room condition and a testing method thereof. The system comprises a movement mechanism in a shielding cavity to be tested and an internal field intensity meter arranged on the movement mechanism, wherein an external field intensity meter and a stepping motor are arranged between the shielding cavity to be tested and a live room, and a computer provided with a stepping motor control card controls the stepping motor through a stepping motor terminal board. The output end of the internal field intensity meter and the output end of the external field intensity meter are connected with the corresponding input ends of the computer through field intensity meter optical fibers respectively. The output end of the stepping motor control card is connected with the input end of the stepping motor terminal board through a dedicated control wire cable, and the output end of the stepping motor terminal board is connected with the stepping motor. Multi-point automatic measurement is adopted in the testing method. The electromagnetic shielding effectiveness testing system under the live room condition and the testing method thereof have the advantages that the repeatability of testing results is improved, measurement is allowed to be carried out on the resonance frequency points of the shielding cavity to be tested, a stirrer does not need to be arranged in the shielding cavity to be tested, and thus the problem that the stirrer cannot be arranged in small size shielding cavities is solved.
Owner:PEOPLES LIBERATION ARMY ORDNANCE ENG COLLEGE
Kneed tuning of antennae in echo chamber, transmitting technique and equipment in symmetry module
InactiveCN1661389AImprove uniformityMagnitude/direction of magnetic fieldsIt equipmentControl system
The present invention relates to a reverberation room antenna stirring tuning and symmetric mode transmitting technique and its equipment. Said equipment mainly is formed from shielding cabinet-shaped cavity body, transmitting system, receiving system, antenna control system and main control system, and the shielding cabinet-shaped cavity body mainly is composed of shielding door, ventilation waveguide window, filter and interface board. Besides, said invention also provides the antenna control system and concrete position and polarization direction arrangement of said transmitting antenna in the reverberation room. Said invented technique can greatly improve low-frequency electromagnetic field uniformity in the reverberation room.
Owner:BEIJING JIAOTONG UNIV
Inversion method utilizing single hydrophone to measure reverberation time of non-anechoic pool
ActiveCN104501939AEasy to measureEasy to operateReverberation timeVoltage amplitudeUltrasound attenuation
The invention relates to a reverberation time measurement method and particularly relates to an inversion method utilizing a single hydrophone to measure reverberation time of a non-anechoic pool. The method comprises steps that, a sound source level of a random non-directional sound source is measured in an anechoic pool by utilizing a calibrated hydrophone and is recorded and loaded to frequency and voltage amplitude on the sound source; the non-directional sound source and the hydrophone are put to a to-be-measured non-anechoic pool, frequency and voltage amplitude are recorded and are loaded to the non-directional sound source, the sound source and the hydrophone are simultaneously and slowly moved, and an average space sound pressure level is acquired by utilizing the hydrophone for measurement; the reverberation time of the non-anechoic pool can be acquired through inversion calculation according to the sound source level of the non-directional sound source in a free field and the measured average space sound pressure level of the sound source in the to-be-measured non-anechoic pool. The method has properties of high test efficiency and accurate result, and the average sound energy density attenuation time can be measured not on the basis of definition of the reverberation time.
Owner:HARBIN ENG UNIV
Test method for measuring sound absorption coefficient of sound absorption or sound insulation material by use of reverberation chamber
InactiveCN102426191AThe sound absorption effect is consistentReduce test areaAnalysing solids using sonic/ultrasonic/infrasonic wavesNoise controlTest efficiency
The invention relates to a test method for measuring the sound absorption coefficient of a sound absorption or sound insulation material by the use of a reverberation chamber and belongs to the technical field of noise control. All equipment is firstly placed in the reverberation chamber. Four microphones are installed inside the reverberation chamber and are respectively connected with four channels of a four-channel test system, which is connected with a power amplifier. The power amplifier is connected with a computer. Then, a signal-generator, the power amplifier and the computer which are positioned on the four-channel test system are turned on so as to enter a software test interface of the computer and calibrate each microphone. Finally, vacant auditoria and reverberation time after the material to be measured is put into the reverberation chamber are measured and recorded, and the sound absorption coefficient of the material to be measured can be obtained after software processing. The test method is simple and easy to operate. By the adoption of the test method, the measurement result consists with the sound absorption effect of the material in practical construction projects, the cost for making test samples is greatly saved, and simultaneously the test efficiency is raised.
Owner:WUXI GISSING AUTO ACOUSTIC PARTS TECH CO LTD
Prediction method for sound insulation performance of car front wall
InactiveCN106979977AReduce workloadAnalysing solids using sonic/ultrasonic/infrasonic wavesSound transmission classEngineering
A prediction method for sound insulation performance of a car front wall is as follows: different thickness of steel plates are installed on sound insulation walls of reverberation chambers and anechoic chambers, and sound transmission loss STL (steel plate) of the different thickness of steel plates is tested; different thickness of different front wall panel materials are attached to the steel plates, and sound transmission loss STL (panel) of the different thickness of different front wall panel materials is tested; and combined sound transmission loss STL (combination) is calculated according to the sound transmission loss STL (steel plate) of the steel plates and the sound transmission loss STL (panel) of the front wall panel materials. Equivalent sound transmission loss of a front wall system is predicted by pre measurement of the sound transmission loss STL (steel plate) of the steel plates and the sound transmission loss STL (panel) of the different thickness of different front wall panel materials, during prediction of sound transmission loss of different front wall systems, the sound transmission loss can be calculated by direct extraction of corresponding pre measured data without cutting of the car front wall, customization of tooling, sealing, and other operation, and the work loading of sound transmission loss testing of the front wall system is greatly reduced.
Owner:GUANGZHOU AUTOMOBILE GROUP CO LTD
Source stirring electromagnetic reverberation chamber and stirring method thereof
InactiveCN104133126AImprove space utilizationLarge test areaElectrical testingField uniformityElectromagnetic reverberation chamber
Disclosed are a source stirring electromagnetic reverberation chamber and a stirring method thereof. The reverberation chamber includes an electromagnetic shielding chamber, a source stirring device installed on the side wall of the electromagnetic shielding chamber, and the source stirring method used for describing installation, motion and control method of an transmitting antenna. Simultaneous change of the position and polarization direction of the transmitting antenna is realized through control of a rotating shaft to rotate. A drive device of the rotating shaft is installed at the outer side of the reverberation chamber and the rotating shaft which is installed on the inner wall of the reverberation chamber is driven to rotate through a changeover mechanism. The reverberation chamber realizes field uniformity in the reverberation chamber through rotation of a single antenna so that space utilization rate in the reverberation chamber is effectively improved and a source stirring reverberation chamber of the same volume can realize a larger test area; relative to an EUT of the same size, a source stirring reverberation chamber which is smaller in volume can be designed so that generation of high field intensity is better facilitated; and the reverberation chamber is also applicable to a condition in which a plurality of transmitting antennae are configured in a reverberation chamber to carry out source stirring.
Owner:陕西海泰电子有限责任公司
Method for automatically calibrating the field intensity distribution characteristics of electromagnetic reverberation chamber
ActiveCN104793163AImprove anti-interference abilityWide frequency rangeElectromagentic field characteristicsElectromagnetic reverberation chamberElectromagnetic field
The invention discloses a method for calibrating the field intensity distribution characteristics of an electromagnetic reverberation chamber. The field intensity of an electromagnetic reverberation chamber can be tested by eight field intensity probes at the same time to acquire the field intensity distribution characteristics. The precision is high, and the speed is high. Spatial field intensity sensors are used to sense spatial 100MHz-18GHz radio-frequency microwave electromagnetic field signals and convert the radio-frequency microwave signals into direct-current signals. The eight channels of signals are transmitted by optical fibers to a data receiving unit after data processing end encoding is carried out and the direct-current signals pass through an electro-optical converter. The field intensity distribution characteristics of the electromagnetic reverberation chamber are calculated and processed through a central processing unit. The method is disclosed to realize accurate measurement of the distribution characteristics of a spatial broadband electromagnetic field. The range of field intensity amplitude measurement is from 1V / m to 200V / m, and the inaccuracy of measurement is 1.5dB.
Owner:CHINA SHIP DEV & DESIGN CENT
Method and device for measuring random incidence sound-absorbing coefficient/sound-absorbing quantity of material
ActiveCN103675104AImprove efficiencyHigh precisionMaterial analysis using acoustic emission techniquesMeasurement deviceEngineering
The invention relates to a method and device for measuring random incidence sound-absorbing coefficient / sound-absorbing quantity of a material. The method comprises the following steps: 1) a signal transmitter module sends out a frequency sweeping sound signal into a reverberation room; 2) a signal acquisition module acquires sound pressure signals of the reverberation room before and after the placing of a test piece respectively; 3) a signal processing module calculates the impulse responses of the reverberation room before and after the placing of the test piece respectively, the sound pressure level attenuation and fitting data of each frequency band, and reverberation time, and calculates the sound-absorbing coefficient / sound-absorbing quantity of the frequency band of the test piece and the noise reduction index NRC; 4) a result display module displays the sound pressure level attenuation and the matched curve of the frequency band, a reverberation time list, and a sound-absorbing coefficient / sound-absorbing quantity list and curve; 5) a storage and statement generation module stores the impulse responses and the results, and generates a test report; 6) an off-line analysis module can perform in-depth signal analysis by invoking the stored impulse responses. The method and device have the advantages of high precision, high speed, integrated data processing and the like.
Owner:TONGJI UNIV +1
Mixing stirring device of mechanical stirring and source stirring of electromagnetic reverberation chamber and method
ActiveCN103558422AImprove performanceImprove field uniformityElectrical measurement instrument detailsElectrical testingField uniformityOrthogonal coordinates
The invention provides a mixing stirring device of mechanical stirring and source stirring of an electromagnetic reverberation chamber. The mixing stirring device comprises the electromagnetic reverberation chamber and further comprises a mechanical stirring assembly and a source stirring assembly, wherein the mechanical stirring assembly and the source stirring assembly are arranged on the side wall of the electromagnetic reverberation chamber. The mechanical stirring assembly comprises a first motor and a mechanical stirrer connected with the first motor; the source stirring assembly comprises a second motor, a rotary shaft connected with the second motor and a transmitting antenna disposed on the rotary shaft. By means of combination of a mechanical stirring device, a source stirring device and a method, change of electromagnetic field distribution in the reverberation chamber depends on more variable changes which include changes of the length, the width and the height of an equivalent reverberation chamber and changes of the position of an excitation current source or / and orthogonal coordinate components of current density, and therefore more choices are provided for further improving field uniformity of a testing area in the reverberation chamber so that performance of the reverberation chamber is more likely to be improved.
Owner:陕西海泰电子有限责任公司
Testing performance of a wireless device
InactiveUS8718122B2Improve abilitiesEfficient testingMultiple-port networksDelay line applicationsEngineeringFading
Improved performance testing of a wireless device is disclosed. The system is particularly suited to testing devices having multiple antennas. The device under test (DUT) is placed in a reverberation chamber with antennas for transmission of a test signal to the DUT. The number of antennas deployed in the reverberation chamber and placement of those antennas is selected such that no line-of-sight transmission component exists from test system antenna to DUT antenna, and the number of antennas deployed in the reverberation chamber is greater than the spatial rank of the signal. The antennas are driven by a programmable channel emulator capable of generating fading, correlation, delay, Doppler and other channel condition phenomena. Furthermore, the antennas are driven individually by a plurality of independent fading processes. The combination of the programmable channel emulator and reverberation chamber creates a multipath environment which simulates signals arriving from different locations, with different delays, as well as the simulation of device motion. The system also includes instruments to produce test signals and to measure the performance of the DUT.
Owner:AZIMUTH SYSTEMS
Background noise energy eliminating measurement method of reverberation time of factory building
The invention provides a background noise energy eliminating measurement method of a reverberation time of a factory building. The method comprises the following steps of arranging a microphone in the factory building, giving out pulse response excitation through a sound source, and collecting a reverberation sound signal by using the microphone; selecting octave center frequency; filtering a frequency range corresponding to the collected signal, so as to obtain a sound pressure signal under the center frequency; choosing one segment of long enough background noise signals at a later-period stable stage to carry out energy integration, so as to obtain a noise energy average value per a unit time; choosing a long enough signal at a reverberation decay-period stage, so as to obtain an attenuation-period sound energy value after background noise energy is eliminated; linearly fitting a sound pressure level decay curve, so as to obtain a fitted gradient, and calculating the reverberation time through the gradient. By using the method, the influence of background interference noise on the measurement of the reverberation time can be removed; the method is applied to a factory building in which the background interference noise exits; the reverberation time of the factory building is measured.
Owner:JIANGSU UNIV
Material electromagnetic pulse shielding effectiveness testing system based on nested reverberation chamber and testing method thereof
ActiveCN103884940AGood repeatabilitySmall coefficient of variationElectrical testingEngineeringElectromagnetic pulse
The invention discloses a material electromagnetic pulse shielding effectiveness testing system based on a nested reverberation chamber and a testing method thereof. The method includes the following steps that (1) testing preparation is performed; (2) when no tested electromagnetic protection materials exist on a window, a main stirrer and a small stirrer rotate according to rules so that data can be acquired; (3) all maximum numerical values in a tested data waveform are collected, a system mean value envelope line is established, and the peak value E0 is collected; (4) when the tested electromagnetic protection materials exist on the window, the step (2) and the step (3) are executed again, and the peak value ES and the field intensity numerical value for representing whether the tested electromagnetic protection materials exist or not through the ES and the E0 are obtained; (5) the electromagnetic pulse shielding effectiveness SEP of the tested electromagnetic protection materials is calculated. The material electromagnetic pulse shielding effectiveness testing system based on the nested reverberation chamber and the testing method thereof have the advantages of being good in repeatability of test results, capable of enabling the variable coefficient to be smaller than five percent, capable of solving the problems that result randomness is high and fluctuation is large in single-point single testing of a traditional shielding effectiveness testing method, suitable for persistent oscillation pulses, variable oscillation pulses and double-exponential pulses, and high in practicability.
Owner:PEOPLES LIBERATION ARMY ORDNANCE ENG COLLEGE
Arrangement And Method For Measuring The Performance Of Devices With Wireless Capability
ActiveUS20190391195A1Mitigate such drawbackHigh data rateTransmitters monitoringReceivers monitoringMeasuring instrumentEngineering
A new measurement arrangement and method for measuring the performance of a device under test, such as an antenna, a mobile phone and other wireless terminals, are disclosed. The chamber defines an internal cavity therein, adapted to enclose the device under test, and including walls of an inwardly reflective material, rendering the walls reflective to electromagnetic waves, thereby simulating a multi-path environment. Thus, the chamber is a reverberation chamber. Further, at least one first chamber antenna and at least one second chamber antenna, are arranged in the cavity, the first and second chamber antennas being configured to transmit and receive electromagnetic waves within a first predefined frequency range and within a second predefined frequency range, respectively. A measuring instrument is connected to the device under test and the chamber antennas, for measuring the transmission between them. Furthermore, a frequency selective absorber is arranged in the cavity, the frequency selective absorber being arranged to absorb electromagnetic waves having a frequency within the first predefined frequency range and reflect electromagnetic waves having a frequency within the second predefined frequency range. Hereby, a measurement arrangement capable of testing of devices having wireless capability according to coming mobile communication standards is presented.
Owner:BLUETEST
Temperature-humidity-electromagnetism integrated environment simulation device
ActiveCN106124911AImprove accuracyThe simulation effect is realWeather/light/corrosion resistanceMeasuring interference from external sourcesElectromagnetic reverberation chamberConnection - action
The present invention belongs to the detection equipment field of the electronic equipment, in particular relates to a temperature-humidity-electromagnetism integrated environment simulation device. The temperature-humidity-electromagnetism integrated environment simulation device comprises an environment test room in which an electromagnetic reverberation chamber is arranged, and a ventilation structure used for ventilating and capable of keeping the original shielding efficiency of the reverberation chamber is arranged on a wall of the electromagnetic reverberation chamber. An electromagnetic interference test environment is provided in the electromagnetic reverberation chamber with the ventilation structure, and the electromagnetic reverberation chamber is not interfered by an external electromagnetic environment. The environment test room is used to adjust the temperature and humidity of the own internal space, and also transmit the relevant temperature and humidity change to the internal space of the electromagnetic reverberation chamber via the connection action of the ventilation structure, thereby changing the temperature and humidity in the electromagnetic reverberation chamber. By the above structure, various tests can be carried out on a same device, various extreme environments of the electronic equipment can be simulated more really, at the same time, the test time is shortened, and the consumption of the manpower and material resources is reduced.
Owner:CHINA AERO POLYTECH ESTAB
Method for measuring transient sound source characteristics in reverberation pool
ActiveCN109238436ASuitable for quantitative acoustic evaluationEfficient measurementVibration measurement in fluidSound sourcesSelf correlation
The invention belongs to the field of acoustic measurement research, and particularly relates to a method for measuring the transient sound source characteristics in a reverberation pool. The method comprises the following steps: placing a standard sound source and a hydrophone array in the reverberation pool; placing a known standard sound source at a position having a distance with a pool wall greater than a minimal analysis frequency wavelength in the pool; placing hydrophones in a whole space in the pool, wherein the maximal distance is greater than a minimal half-wavelength, and line array placement and single placement via a bracket are adopted during the placement; causing the known standard sound source to emit a steady state broadband signal, and measuring a frequency domain soundfield correction amount of the reverberation pool; replacing the standard sound source with a transient sound source to be measured for emission, and collecting time domain sound pressure data; performing power spectrum calculation on the time domain data of all array elements to obtain a sound power level (the formula is described in the specification), and performing space average processing toobtain a spatial average sound power level (LW); and performing self-correlation processing on the time domain data fn(t) of all array elements. The invention provides a pool measurement method of transient sound characteristics, which is suitable for the quantitative acoustic evaluation of transient sound, and the method has the advantages of relatively good stability, easy implementation of measurement conditions, high measurement efficiency, etc.
Owner:HARBIN ENG UNIV
Reverberation chamber with improved electromagnetic field uniformity
InactiveUS20160131689A1Improve uniformityLow usable frequencyFault location by increasing destruction at faultElectromagentic field characteristicsEngineeringElectromagnetic field
The reverberation chamber comprises a shielded enclosure (10) made up of a floor (11), side walls (13 to 16), and a ceiling (12), together with an antenna (2) for emitting radiofrequency waves in order to generate radiation inside the enclosure (10) at a lowest usable frequency. The chamber also comprises, inside the enclosure (10), a set (5, 6) of passive and selective elements for absorbing radiofrequencies in a defined frequency band.
Owner:CENT NAT DE LA RECHERCHE SCI +2
Method and system for enhancing reverberation room internal field intensity and simulating compound field electromagnetic environment
ActiveCN108132390AHigh test spaceHigh field strength test spaceElectromagentic field characteristicsElectrical conductorSynthesis methods
The invention provides a method and a system for enhancing reverberation room internal field intensity and simulating compound field electromagnetic environment. According to the method, the multi-frequency high-field-intensity complex electromagnetic environment is simulated by using a reverberation room, and the high field intensity in the test area is acquired by using the space synthesis method of the same frequency microwave power in the reverberation room; the multi-frequency compound field of the test area is acquired by using a different frequency incoherent resonance method; and multiple movable light closed good conductor metal boxes are arranged in the reverberation room so that the ineffective space of the reverberation room at the high end of frequency can be reduced and the field intensity amplitude of the test area can be enhanced. The system comprises the reverberation room, multiple movable light closed good conductor metal boxes, a radio frequency signal source, a power distributor, power amplifiers, a directional coupler, a circulator, a power meter, a transmitting antenna, a receiving antenna, an optical fiber field intensity meter, a spectrum analyzer and a measurement and control and data acquisition computer. The internal field intensity amplitude of the reverberation room is enhanced by using multiple power amplifiers and adjusting the internal structureof the reverberation room so as to simulate the multi-frequency complex electromagnetic environment in the reverberation room.
Owner:CHINA SHIP DEV & DESIGN CENT
Sound insulation measurement system based on hand-held sound intensity probe suite
PendingCN109187759ASimple structureEasy to testAnalysing solids using sonic/ultrasonic/infrasonic wavesResponse signal detectionHand heldData acquisition
The invention discloses a sound insulation measurement system based on a hand-held sound intensity probe suite. The sound insulation measurement system based on the hand-held sound intensity probe suite comprises a complete elimination chamber and a reverberation room which are separated through a wall surface, the center of the wall surface is provided with a window which divides the complete elimination chamber and the reverberation room completely through sealing installation of a sample piece to be tested, and the reverberation room is internally and uniformly provided with a plurality oflow-frequency loudspeakers, high-frequency loudspeakers and microphones. The complete elimination chamber is provided with the hand-held sound intensity probe suite, a data acquisition system and hardware and a test computer. The data acquisition system and hardware is in circuit connection with the low-frequency loudspeakers and the high-frequency loudspeakers through an audio control unit to constitute an original signal output module. The hand-held sound intensity probe suite and the microphones are separately connected with the data acquisition system and hardware, and the data acquisitionsystem and hardware is connected with the test computer. According to the sound insulation measurement system based on the hand-held sound intensity probe suite, the structure is simple, the test process is easy to adjust, the sound insulation measurement system is convenient to move, meanwhile, sound insulation measurement results are reliable, and the cost is low.
Owner:SOUTH CHINA UNIV OF TECH
Device for measuring sound absorption and sound insulation coefficients of underwater acoustic material based on reverberation method
ActiveCN105973979AThe acoustic state does not changeEasy to implementAnalysing solids using sonic/ultrasonic/infrasonic wavesAcoustic waveEngineering
The invention belongs to the field of acoustic measurement, and in particular, relates to a device for measuring sound absorption and sound insulation coefficients of an underwater acoustic material based on a reverberation method. The device includes a first reverberation box, a second reverberation box and a third reverberation box; structures of the first reverberation box and the second reverberation box are the same, are each a cuboid structure, each have no top cover and are prepared by welding steel plates; the center of the side part of the first reverberation box and the center of the side part of the second reverberation box are welded with flanges; one side of the first flange is provided with a first organic glass plate, one side of the second flange is provided with a second organic glass plate, and the other sides of the flanges are connected with the third reverberation box; the bottom parts of the first reverberation box and the third reverberation box are provided with pin rollers. Acoustic states of the first reverberation box and the second reverberation box can be guaranteed to be not changed, the influence of an experimental error in the process of measurement is reduced, the ability of acoustic waves in the first reverberation box propagated from the third reverberation box to the second reverberation box is weakened, and the influence of boundary conditions in the process of measurement is reduced.
Owner:HARBIN ENG UNIV
Systems and methods to stir an electromagnetic (EM) field
InactiveUS8035370B2Resistance/reactance/impedenceDynamo-electric motor metersCharged particleQuantum mechanics
Systems and methods to stir an electromagnetic (EM) field of an EM reverberation chamber are disclosed. A particular system includes an EM reverberation chamber. The system also includes a transmit antenna and a receive antenna operable to generate an EM field within the EM reverberation chamber. The system further includes a variable charged particle source to stir the EM field by varying introduction of charged particles into the EM field.
Owner:THE BOEING CO
Method for testing shielding effectiveness of textile material under complex electromagnetic environment
ActiveCN103743985AThe test results are simple and clearTest results are stableElectrical testingElectrical field strengthWorking environment
The invention discloses a method for testing the shielding effectiveness of a textile material under a complex electromagnetic environment. The method comprises the following steps: (1) establishing a hollow metal cavity, wherein the hollow metal cavity is put in a reverberation room, and a window and a first waveguide hole are formed in the surface of the hollow metal cavity; a field intensity meter and a first stirrer are arranged in the hollow metal cavity; (2) constructing a reverberation room work environment; (3) enabling the to-be-tested textile material to closely cover the window, enabling the stirrer, recording electric field intensities acquired by the field intensity meter when the stirrer does step-by-step rotation each time, and computing an average electric field intensity value as E1; (4) removing the to-be-tested textile material on the window, keeping the field intensity meter in the step 1 unchanged in position, keeping all parameters in the step 3 constant, and computing an average electric field intensity value as E2; (5) computing the shielding effectiveness SE of the to-be-tested textile material by adopting a formula SE=20*log(E1 / E2) (1). The method disclosed by the invention has the advantages that the operation is simple and fast; a testing result is accurate and reliable, and not influenced by the size of the window.
Owner:PEOPLES LIBERATION ARMY ORDNANCE ENG COLLEGE
Method for testing textile material shielding effectiveness based on live room condition
ActiveCN103777099AAssessing Electromagnetic Shielding CapabilitiesAvoid influenceElectrical testingLiving roomElectromagnetic shielding
The invention discloses a method for testing the textile material shielding effectiveness based on a live room condition. The method comprises the steps that (1) a small-type mechanism stirring live room is made of a textile electromagnetic shielding material to be tested; (2) a nested live room is manufactured; (3) the frequency of a signal source is set, a large live room is radiated by electromagnetic waves through a transmitting antenna, and stirrers in the large live room and the small live room are started; (4) electric field average values Eout and Ein in a stirring period of the large live room and the small live room are measured; (5) the shielding effectiveness SE of the textile electromagnetic shielding material to be tested is calculated; (6) if it is judged that test frequency points in a required number are completed, a test is finished, and otherwise, the steps are repeated from the step (4). The method has the advantages that a test result is prevented from being affected by the hole and seam coupling effect of a test window, operation is simple and convenient, the method is more suitable for testing the capacity, for shielding the electromagnetic waves, of the textile electromagnetic shielding material to be tested which is stretched to different strengths and different shapes, the result is accurate, and the repeatability is good.
Owner:PEOPLES LIBERATION ARMY ORDNANCE ENG COLLEGE
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