104results about "Impedence" patented technology

An apparatus and method are provided for the in-situ measurement of the stiffness of a layer of soil or other surface of interest. The apparatus includes a contact foot for engaging the surface and a drive transducer coupled to the contact foot for applying a vibratory force to the contact foot in response to a drive signal. A motion sensor is coupled to the contact foot and in a preferred embodiment an additional sensor measures the force applied to the contact foot and hence to the surface. These sensors generate corresponding output signals. The output signals are used to generate a measurement signal that is representative of the surface stiffness.

A nondestructive method of and apparatus for detecting degradation of reinforcing members embedded within a structure is disclosed. Degradation can arise from many sources, such as corrosion, fracture, cracking, fatigue, chemical reaction, etc. The device includes an inducing instrument(210) to induce a vibration of the reinforcing members (110)and a measuring device (220) to detect the vibration of the reinforcing members. The measurement is analyzed to detect the presence of reinforcing member degradation or reinforcing member-to-concrete bonding. The device may include a controller (230) to enhance the detection. The device may also include an amplifier (240) to further increase the energy in the waves imparted to the structure and the acoustic waves detected by the measuring instrument.(220)

Disclosed is a technique for localizing a sound source. In the technique, a sound pressure signal measured by microphones is acquired using a spherical microphone array sensor where the microphones are fixedly arranged on a surface of a spherical body. A sound pressure distribution on the surface of the spherical body is obtained by a controller from a sound pressure calculation formula for calculating a sound pressure at a certain location of a spherical surface using the sound pressure signal measured by the microphones as an input value. A location of the sound source is estimated from the obtained sound pressure distribution.

Tools and methods are provided that determine the acoustic impedance of drilling fluid using reflections from a precise metal disk. Because the reverberation characteristics of an acoustic wave depend in part on the acoustic wave shape, the first reflection from the metal disk may be used to calibrate the measurement. A method for determining a borehole fluid property includes (i) generating an acoustic signal within a borehole fluid, (ii) receiving reflections of the acoustic signal from the fluid, and (iii) analyzing a reverberation portion of the acoustic signal to determine the property. The analyzing of the reverberation portion may include obtaining a theoretical reverberation signal and relating the measured reverberation signal with the theoretical reverberation signal to determine the borehole fluid property.

The transfer function of the communication channel in a mud pulse telemetry system is determined by sending a known signal through the channel and spectral analysis of the received signal. The known signal may be a chirp signal or a stepped frequency signal. Based on the determined transfer function, operating parameters of the pulser are adjusted.

The present invention provides a method of measuring an acoustic impedance of a respiratory system. The method comprises selecting a frequency range for an acoustic wave, directing the acoustic wave into the respiratory system and receiving an acoustic wave from the respiratory system. The method also comprises determining the acoustic impedance for a plurality of volumes or volume ranges of the respiratory system. Each volume, or the volumes within each volume range, is larger than RV or FRC and smaller than TLC whereby the determined acoustic impedances are specific for respective volumes or volume ranges. Further, the method includes determining a volume, or volume range, dependency of the acoustic impedance of the respiratory system and charaterising the respiratory system by analysing the dependency of the acoustic impedance on the volume or volume range.

The invention relates to a sensor (1) and a method for measuring pressure, variation in sound pressure, a magnetic field, acceleration, vibration, or the composition of a gas. The sensor (1) comprises an ultrasound transmitter (2), and a cavity (4) arranged in connection with it. According to the invention, the sensor (1) comprises a passive sensor element (3, 3') located at the opposite end of the cavity (4) to the ultrasound transmitter (2), the distance of which from the ultrasound transmitter (2) is selected in such a way that the resonance condition is met at the ultrasound frequency used, the ultrasound transmitter (2) comprises a light-construction diaphragm oscillator (9), which is thus well connected to the surrounding medium, and the sensor includes means for measuring the interaction between the ultrasound transmitter (2) and the cavity (4).

An acoustic sensor capable of improving the sensor S / N ratio, without impeding reduction in sensor size is provided. A back chamber (45) opens at the top and bottom to a silicon substrate (42). A thin-film diaphragm (43) which serves as a movable electrode plate is formed on the upper surface of the substrate (42) so as to cover the back chamber (45). Back plates (48) are fixed to the upper surface of the substrate (42) so as to cover the diaphragm (43) and fixed electrode plates (49) are disposed on the lower surface of the back plates (48). In addition, the diaphragm (43) is divided into a plurality of areas by a slit (47), and a plurality of capacitors (acoustic sensing sections) (60a, 60b) connected in parallel are configured by each of the plurality of divided diaphragms (43a, 43b) and the fixed electrode plates (49).

Systems and methods for detecting faults are provided. A method for determining a fault condition for a component of a drivetrain in a wind turbine can include receiving an acoustic signal from an acoustic signal measuring device. The method can further include receiving a vibration signal from a vibration signal measuring device. The method can further include analyzing the acoustic signal to determine an analyzed acoustic signal. The method can further include analyzing the vibration signal to determine an analyzed vibration signal. The method can further include determining a fault condition for the component based at least in part on the analyzed acoustic signal and analyzed vibration signal. The fault condition can further be determined based at least in part on an analyzed electrical signal.

The invention provides a soft measurement method and a soft measurement system of tool nose point displacement mobility of a machining center, and belongs to the technical field of vibration measurement. Experimentation testing is combined with finite element analysis to conduct the soft measurement of the tool nose point displacement mobility on tools which are arranged in the machining center and have different geometrical characteristics. According to the soft measurement method and the soft measurement system of the tool nose point displacement mobility of the machining center, direct testing of p2b2b and n2b2b is avoided, instead, the p2b2b and the n2b2b are solved through testing of H11 and H12, H11 and H12 are values which are easier to test, times of experimental tests are reduced, the tool nose point displacement mobility of all tools in a machining center tool magazine can be theoretically forecasted through a plurality of times of tests after the tools are installed, the test cost and test expenses are greatly reduced, no accurate modeling needs to be conducted on main shaft-tool handle, forecasted result incredibility caused by errors in a modeling process and errors in a parameter identification process is avoided, and maneuverability is strong when the soft measurement method and the soft measurement system of the tool nose point displacement mobility of the machining center are applied to engineering. According to the soft measurement method and the soft measurement system of the tool nose point displacement mobility of the machining center, a plurality of times of theoretical prediction can be conducted after one test, obtained tool nose point displacement mobility is the basis for forecasting flutter, and milling machining flutter forecasting can be conducted.

A method, device, system, program and recording medium for impulse response measurement which can improve a measurement accuracy without lowering the S / N ratio over the whole range, from lower frequencies to higher frequencies, of a measuring signal are provided. A signal generation unit (21) of a device for impulse response measurement (10-1) generates a W-TSP signal (x(t)) having characteristics of a TSP signal and a Log-TSP signal. A D / A conversion unit (22) converts the digital signal (x(t)) into an analog signal (x(t)) and outputs the converted signal to a headphone (2) or a speaker (5). An A / D conversion unit (23) inputs an analog signal (y(t)) received by a microphone (3) or a microphone (6) and converts the inputted signal into a digital signal (y(t)). An inverse signal generation unit (24) generates an inverse W-TSP signal (x(t)). A convolution unit (25) convolutes the signal (y(t)) and the inverse W-TSP signal (x−1(t)) thereby to calculate an impulse response (g(t)).

The invention relates to a method and an apparatus for detecting that a device is immersed in a liquid. The method comprises: receiving, by an electronic device, a first signal having a first frequency; identifying, by the electronic device, at least one of a strength of the first signal or a signal-to-noise ratio of the first signal; outputting, by the electronic device, a second signal having a second frequency that is different from the first frequency, the second signal being output based on at least one of the strength of the first signal or the signal-to-noise ratio of the first signal; receiving the second signal by the electronic device; and detecting whether the electronic device is at least partially immersed in a liquid based on the received second signal.

The invention relates to a measuring system for material normal direction incidence acoustical absorption coefficient and acoustic impedance. The measuring system comprises a signal transmitter module, an impedance tube, a signal acquisition module, a signal processing module, a signal display module and a report generation module, wherein the signal transmitter module, the impedance tube and the signal acquisition module are connected in sequence, the signal processing module is respectively connected with the signal acquisition module, the signal display module and the report generation module, the signal transmitter module sends out single frequency sinusoidal acoustical signals to the impedance tube, the signal acquisition module acquires the acoustic pressure signal in the impedance tube in real time, and transmits to the signal processing module, the signal processing module displays the received real time acoustic pressure signal through the signal display module, the material normal direction incidence acoustical absorption coefficient and acoustic impedance are calculated through the adoption of a standing wave ratio method, finally the calculated result is generated through the report generation module, and a testing report is stored. Compared with the prior art, the measuring system has the advantages that the measuring process is straightforward, and the measuring accuracy and efficiency are high.

A method of providing visualization information of a rear vehicle includes calculating a location of a sound source located behind a host vehicle, using a sound signal received by each of a plurality of microphones, matching information about the location with an object displayed on image information generated by a rear camera, and displaying a first icon indicating the object on the image information, where the first icon includes information about a probability that the object is present in an area indicated by the location information.

A probe located in an area to be measured has an acoustic stimulator, (e.g., a loudspeaker and a microphone). The stimulator sends acoustic signals to the microphone where the signals are transformed into electrical signals and transferred to an analysis unit. Using a defined stimulation followed by a two-port chain transfer matrix connected to an impedance as a model, the voltage ratio between the stimulation and the impedance is described as a dimensionless transfer function of a complex function of the stimulation frequency. A series of acoustic calibration signals are generated by known acoustic impedances covering different calibration scopes using the stimulation. The calibration signals are recorded and the electric values are merged with the respective voltage values of the stimulation for evaluation of the respective transfer functions which are merged together into an over-determined linear system of equations. The impedance is determined by evaluating the transfer functions.

The invention discloses an acoustic liner acoustic impedance measurement method under a condition of acoustic wave grazing incidence. The method includes the steps of installing an acoustic liner on a side wall of a sound transmitting tube having a rectangular cross section; obtaining wall sound pressure of the position where M measurement points are selected on an opposite side to the side wall where the acoustic liner is located; based on modal characteristics of sound propagation in a tube, enabling the wall sound pressure of the sound tube to be written in an exponential function superimposed form, so that the number of axial wave of sound propagation in the sound tube can be identified through a Prony method; then extracting acoustic impedance in two cases, an when the gas in the sound tube is uniform flow, obtaining the acoustic impedance simply by using a simple dispersion relation and an eigenvalue equation; and when the gas in the sound tube is shear flow, obtaining the acoustic impedance by using an impedance boundary condition after a Pridmore-Brown equation is numerically solved. The advantages of the invention lie in that compared with conventional extraction methods, the acoustic liner acoustic impedance measurement method greatly simplifies the extraction process, reduces the number of measurement points of the wall sound pressure, and is free from the influence of reflection from an outlet; and the invention provides a novel test method for the industry community.

The invention discloses a device and a method for testing the impedance characteristic and the expansion performance of a sound absorption material, and relates to the technical field of material performance detection. The device comprises a first cavity and a second cavity which are sealed cavities, a sound excitation source and two pickup sensors, wherein the first cavity is communicated with the second cavity through a narrow channel; the sounding surface of the sound excitation source is positioned in the first cavity; the two pickup sensors are respectively arranged in the first cavity and the second cavity and are respectively used for detecting sound pressures in the first cavity and the second cavity; materials for encircling the first cavity and the second cavity are sound isolation materials. According to device and the method, the technical problem that the sound absorption material is difficultly selected in the prior art is solved; performance test on the sound absorption material is realized; a technical index is provided for the selection of the sound absorption material; the production cost of an acoustic product is reduced, and higher economic benefits are created for the enterprise.

The invention discloses a method for measuring deicing jump damping coefficients of an iced power transmission line. The method comprises the following steps that a time-displacement curve under the deicing jump of the test power transmission line is measured; simulation power transmission lines identical with the test power transmission line in initial state and deicing condition are calculated according to a formula (please see the formula in the specification), and time-displacement curves under the different damping coefficients are calculated; in the time-displacement curves of the simulation power transmission lines under the different damping coefficients, the time-displacement curve of the certain simulation power transmission line close to the time-displacement curve of the test power transmission line is selected, and the damping coefficient corresponding to the time-displacement curve of the certain simulation power transmission line is used as the damping coefficient of the test power transmission line under the initial state. The method can obtain the accurate damping coefficients of the test power transmission line.

The invention discloses a sound field monitoring method and a monitoring system for a thermoacoustic engine. The method comprises the follow steps of: (1) measuring the sound pressure of the working fluid in a thermoacoustic system tube with at least two sound pressure sensors; (2) reconstructing the sound pressure distribution of the fluid in the tube with the sound pressure measured by any two sound pressure sensors; (3) reconstructing the local velocity distribution of the fluid in the tube; (4) reconstructing the acoustic impedance distribution inside the tube; (5) reconstructing the reflection factor distribution inside the tube; and (6) reconstructing the sound intensity distribution inside the tube. The monitoring system comprises at least two pressure measuring holes opened on the wall of a measured tube of the thermoacoustic engine, and at least two sound pressure sensors are sealed in the pressure measuring holes corresponding to the pressure measuring holes; the sound pressure sensor is connected with a corresponding signal conditioner, the output signal of the signal conditioner is transmitted to a signal processing device, and the processed result is output and displayed on an output display apparatus. The invention has the advantages of real-time diagnosis and monitoring, and high accuracy.

An acoustical wave measuring apparatus capable of achieving an acoustic match even when the shape of a holding member changes largely along a scanning direction of a probe, including a holding member which holds a test object, a probe which receives an acoustical wave, and a sealing member, and the acoustical wave is received by running the probe for scanning with respect to the holding member while an acoustic matching agent for performing acoustic impedance matching between the probe and the holding member is injected into between a receiving surface and the holding member. The sealing member includes a portion with elasticity arranged at the receiving surface of the probe and is biased in a direction which brings the sealing member into contact with the holding member such that the portion contacts the holding member to seal a space between the receiving surface and the holding member.

A sound focusing mechanism for generating a focused source of sound, which can be used to identify the transmission loss of an object or identify areas of acoustic leakage is disclosed. The sound focusing mechanism includes a housing having at least one wall formed from a material having high sound insulating properties. A sound generating device for generating a sound is located within a central cavity within the housing. An actuator assembly is operatively connected to the sound generating device for selectively operating the sound generating device. The wall is configured to limit the transmission of the sound there through such that a focused beam or pulse sound is emitted from the mechanism through the opening.

The invention belongs to the field of vibration testing technology, and particularly relates to a device and a method for testing the non-linear rigidity and damping of a hard coating composite structure. The device comprises a pulse excitation device, a vibrating table, a power amplifier, a data acquisition and analysis instrument, a laser vibration measurement instrument and an upper computer, wherein the hard coating composite structure is fixedly arranged on the top of the vibrating table; an output end of the pulse excitation device is connected with one input end of the data acquisition and analysis instrument, the other input end of the data acquisition and analysis instrument is connected with an output end of the laser vibration measurement instrument, one output end of the data acquisition and analysis instrument is connected with an input end of the power amplifier, an output end of the power amplifier is connected with the vibrating table, the other output end of the data acquisition and analysis instrument is connected with the upper computer. Through the method, testing on vibration parameters of a hard coating composite structure can be efficiently completed with target, and the method is used for quantitatively evaluating the vibration reduction effect of damping of a hard coating and objectively evaluating the non-linear rigidity and damping characteristics of a hard coating composite structure.

The invention discloses a ground surface sound impedence rate measuring device and a ground surface sound impedence rate measuring method. The device comprises a sound wave emission system, a device for detecting a sound pressure level of the ground surface to be tested, and a device for detecting a vibration speed of the ground surface to be tested, wherein the sound wave emission system comprises a signal generator, a sound console, a power amplifier, a loudspeaker, a sound level meter and a computer; the device for detecting the sound pressure level of the ground surface to be tested comprises a sound wave emission system, a sound level meter and a computer; and the device for detecting the vibration speed of the ground surface to be tested comprises a sound wave emission system, a seismic detector array, a multi-channel data acquisition unit and a computer. The sound wave emission system emits high-intensity low-frequency sound waves, the device for detecting the sound pressure level detects a sound pressure level of the ground surface to be tested, the device for detecting the vibration speed of the ground surface detects a vibration speed on the ground surface, and a ratio of the sound pressure level and the vibration speed on the ground surface is a ground surface sound impedence rate. By the ground surface sound impedence rate measuring device and the ground surface sound impedence rate measuring method, the ground surface sound impedence rate can be quickly measured at high accuracy.

A sound focusing mechanism for generating a focused source of sound, which can be used to identify the transmission loss of an object or identify areas of acoustic or thermal leakage is disclosed. The sound focusing mechanism includes a housing having at least one wall formed from a material having high sound insulating properties. A sound generating device for generating a sound is located with a central cavity within the housing. An actuator assembly is operatively connected to the sound generating device for selectively operating the sound generating device for selectively operating the sound generating device. The wall is configured to limit the transmission of the sound there through such that a focused beam or pulse sound is emitted from the mechanism through the opening.

According to embodiments of the invention, an ultrasound device is provided. The ultrasound device includes an ultrasonic transducer, and a resonance matching circuit electrically coupled to the ultrasonic transducer, wherein the resonance matching circuit is configured to cooperate with the ultrasonic transducer to generate, from an impedance of the ultrasonic transducer, an effective impedance at a resonance condition of the ultrasonic transducer to provide a gain to an electrical signal generated by the ultrasonic transducer and to reduce a noise figure of the ultrasound device at the resonance condition. According to further embodiments of the invention, a method for forming an ultrasound device and a method for controlling an ultrasound device are also provided.

The invention provides a method for testing mechanical impedance of a vibration isolator by considering the influence of a base. The flexible base with the limited mass and the limited rigidity can beused in a testing process; the influence of the characteristics of the base on the mechanical impedance of the vibration isolator can be considered; and the defect of a blocking method can be compensated, so that the obtained mechanical impedance can better conform to the mechanical impedance characteristics of the vibration isolator in an actual vibration isolation system. According to the method, a special impedance table no longer needs to be used for testing, so that the testing conditions are reduced and the testing cost is reduced; and the problem of a testing error caused by the fact that the impedance table does not meet the "blocking" requirement is not required to be considered.

The present invention provides a method of measuring an acoustic impedance of a respiratory system. The method comprises selecting a frequency range for an acoustic wave, directing the acoustic wave into the respiratory system and receiving an acoustic wave from the respiratory system. The method also comprises determining the acoustic impedance for a plurality of volumes or volume ranges of the respiratory system. Each volume, or the volumes within each volume range, is larger than RV or FRC and smaller than TLC whereby the determined acoustic impedances are specific for respective volumes or volume ranges. Further, the method includes determining a volume, or volume range, dependency of the acoustic impedance of the respiratory system and characterizing the respiratory system by analyzing the dependency of the acoustic impedance on the volume or volume range.

The invention provides an acoustic liner mounting device applied to a microphone array method acoustic impedance test system. The acoustic liner mounting device comprises an acoustic liner mounting groove and an acoustic liner which are connected with an acoustic liner experiment test section; ear plates are arranged at the two ends of the top surface of the acoustic liner mounting groove, and areembedded into the acoustic liner experiment test section; steps matched with the acoustic liner are arranged on the ear plates on the two sides, and the acoustic liner is installed in the acoustic liner mounting groove through the steps. the top surface of the acoustic liner mounting groove is flush with the acoustic liner experiment test section, and the airflow surface of the acoustic liner isflush with the airflow surface of the acoustic liner mounting groove. According to the acoustic liner mounting device applied to the microphone array method acoustic impedance test system, the problems of low assembly precision, poor sealing performance and low measurement precision of an existing acoustic liner mounting device are well solved.