133 results about "Reverberation room" patented technology

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.