163 results about "Sound level meter" patented technology

The invention provides intelligent environmental noise and vibration monitoring device and method. The device and method are characterized in that equivalent traffic flow and vehicle speed and other parameters of the road traffic in the monitoring period can be converted by a recommending device or system while the environmental noise and the road traffic noise indexes can be measured through the general sound level meter or a statistic analyzing device and a plurality of index values of the noise are measured; therefore, the field investigation of the road traffic noise can be performed conveniently; meanwhile, an FPGA (Field Programmable Gate Array) embedded system can be used for continuously expanding other synchronous detection functions of the environmental noise, so as to realize an intelligent system.

The invention relates to a device for nondestructive testing of defects of hoxiu pears and a use method, which belong to the technical field of agricultural engineering. The device for the nondestructive testing of internal and external defects of the hoxiu pears is characterized in that the device comprises an illumination system, a transfer system, a detection system and an analytical judgment system; a camera and an image acquisition card acquire a fruit body image, and each sample is knocked by a knocking stick with a force of 15N for two times at both ends of the equator of a fruit body; and an audio signal and an image signal of the sample recorded by a sound level meter are converted and enter an industrial computer for image and acoustic analysis treatment after the fast Fourier transform to obtain a classification result of the sample. The device optimally utilizes computer vision information and vibration spectrum information to perform system identification and detection on the internal and external defects of the hoxiu pears, and has the advantages of quickness, accuracy, stability, broad identification range and the like. The device can be used for aspects of the hoxiu pears such as separation, control of processing process and the like, and is favorable for improving the sales added value of the hoxiu pears.

The invention provides an equal-loudness contour-based loudness compensation method, which comprises the following steps of: regulating a volume of an input signal, measuring sound pressure levels corresponding to all available volume values, and in each sound pressure level, filtering an input signal by using a preset frequency filter, and multiplying by a weighting coefficient of the preset frequency filter to obtain a signal; and superposing the input signal in each sound pressure level in a plurality of sound pressure levels corresponding to all the available volume values and the signal obtained through filtering and weighting. The method overcomes the defect that when the conventional audio signal is small in volume, the loudness of partial frequency band is too low, and ears of a human body cannot feel the loudness, so that the heard sound is dry and tedious; by the method, the loudness of input signals of partial frequency band is compensated, the sound is loud and full and meets the requirement of people on acoustic comfort; moreover, a sound level meter and the filter and simple computation are only required to realize the loudness compensation of the audio signal, so that the structure is simple and the cost is low.

A drainpipe noise detection chamber is composed of a chamber body, a catchment pool, a water supply and drainage system and a test equipment. The chamber body adopts a steel frame structure and has an upper layer and a lower layer; the floor, the wall structure body as well as the windows and doors are made of insulation materials; the catchment pool is arranged under the first layer; the water supply and drainage system is arranged in the chamber; during detection, a computer, a sound level meter and a transducer are arranged at each test point based on requirements so as to accurately detect the noise in the pipes and fittings. After the detection chamber is established, the background noise is lower than 25dB(A); the detection chamber can complete drainage noise test for 4 standpipes at the same time, and can achieve unmanned operation in the chamber during noise detection so as to avoid man-made disturbance in the noise test. The establishment of the detection chamber provides a test environment for the noise contrast of various pipe fittings; and the noise detection method is simple and practical, providing a platform for the development of low-noise tube drainage pipes.

Provided is an envelope demodulation frequency band determination method based on harmonic-to-noise ratio. The method comprises: adhering a vibration acceleration sensor on the bearing pedestal of a tested antifriction bearing or installing a sound level meter on the position close to the upper part of the bearing pedestal, so as to acquire signals; establishing a tree filter bank to perform band-pass filtering on original signals; through Hilbert transformation, obtaining envelope of signals, using logarithm spectrum estimation to estimate envelope signal harmonic-to-noise ratio, and using the harmonic-to-noise ratio value as an index of whether frequency band fault features are significant; and finally, using the frequency band whose harmonic-to-noise ratio is the maximum as an optimal envelope demodulation frequency band, and analyzing the optimal envelope demodulation frequency band to determine occurrence and the type of the fault. The method makes full use of periodicity of impact caused by the fault, and uses the envelope harmonic-to-noise ratio as the index to measure the fault, thereby overcoming defects of a conventional kurtosis index. The method has robustness, and can adaptively extract the optimal filtering frequency band, and is beneficial for realizing antifriction bearing fault feature adaptive extraction and automation of diagnosis and monitoring.

The invention relates to a high-speed train gearbox no-load running-in test bench, which is composed of a driving device, axle end transition bearing positioning clamping devices, a large-span mobile wheel set axle positioning supporting device, a gearbox input end pressing vertical column device and a noise testing device, wherein the driving device is arranged at the left end of a test bench base (1); a fixing-end and a mobile-end transition bearing positioning clamping devices are arranged at the left side and the right side of the test bench base (1) respectively; the large-span mobile wheel set axle positioning supporting device is composed of two sets of large-span mobile wheel set axle positioning supporting devices with the same structure; the gearbox input end pressing vertical column device is arranged on the test bench base (1); and the noise testing device comprises noise testing sound level meters and supporting tube assemblies arranged at the input end and the output end of the gearbox respectively. A series of technical problems that the existing gearbox no-load running-in test bench is complicated to assemble and disassemble, an axle journal is damaged, a high rotation speed can not be met and the like can be solved.

The invention discloses an experimental method for intelligent detection of poisonous and harmful gas alarm equipment and a device thereof. Different raw material gases enter a mixer after passing through a high-pressure valve, a pressure gauge, a pressure-reducing valve and a mass flow controller respectively; a gas output from the mixer enters a detected instrument through a flow meter. The mass flow controller is controlled through a computer program to blend needed gases with different concentrations; and sound and image output signals of the detected instrument are input into a computer through an image acquisition and recognition device and a sound level meter, analyzed and calculated by a program and printed and output. Fully automatic detection and report generation of the poisonous and harmful gas alarm equipment are realized by applying computer technology, so the working efficiency of detection is improved. More importantly, the method can greatly enhance the reliability and correctness of detection work, reduce personal error and lower the possibility of contacting poisonous and harmful gases by workers. A metering detection regulation can also be completed according to a detection means.

The invention provides a noise tester of an engine belt tightener. The noise tester comprises a sound-proof housing, a base, a sound level meter, a microphone, a stepping motor and an engine gear system, wherein a tightener to be detected is arranged in the engine gear system; the engine gear system and the microphone are arranged in the sound-proof housing; the microphone is close to the end surface of a belt pulley of the tightener to be detected; a data line of the microphone is connected to the sound level meter outside the sound-proof housing; a driving wheel of the engine gear system is connected with the stepping motor outside the sound-proof housing through a transmitting shaft; and the stepping motor and the sound-proof housing are arranged on the base. The noise tester is used for measuring the magnitude of noise generated when the tightener operates, therefore the installation difficulty when the tightener is tested can be reduced, and the test efficiency is improved; meanwhile the interference from other noises can be reduced, and the noise test result of the tightener is improved.

The invention relates to the technical field of glass performance testing, especially simultaneous testing of sound insulation of sound-insulating glass and non-sound-insulating glass, and particularly discloses a glass sound insulation comparing device. The glass sound insulation comparing device comprises a signal generator, a loudspeaker and two sound level meters with spectrum analyzing functions, and further comprises a sound insulation testing box, a first sound-insulating plate and a second sound-insulating plate, wherein the first sound-insulating plate partitions the sound insulationtesting box into a reverberation zone and a testing zone; the second sound-insulating plate partitions the testing zone into a first testing zone and a second testing zone; the loudspeaker is fixed into the reverberation zone; a first window and a second window are formed in the first sound-insulating plate; the two sound level meters with the spectrum analyzing functions are mounted inside the first testing zone and the second testing zone respectively. The glass sound insulation comparing device can simultaneously test the sound insulation of the sound-insulating glass and the non-sound-insulating glass, so that more intuitive sound insulation comparison is achieved and the sound insulation testing efficiency is improved; the glass sound insulation comparing device can reduce interference of the external environment on a testing process and a testing result, so that the testing result is more accurate.

The invention discloses a micro-surfacing mixture noise indoor-test method which relates to a micro-surfacing mixture noise test method, aiming at solving the problems in the prior art that micro-surfacing road noise is difficulty tested, evaluated and estimated with effectiveness before the construction, and the selection of micro-surfacing mixture gradation is not benefited. The test method mainly comprises the following steps of: 1, selecting a lab; 2, preparing a micro-surfacing mixture test piece; 3, mounting the test piece; 4, selecting and mounting a sound level meter; 5, pretreating the test piece, checking a wear tube before test, replacing the wear tube and then starting the test if the wear tube is severely worn, starting a wet wheel abrader in order to avoid instability in operation when the instrument is started, so that the wear head rotates for 10 seconds and stops, and slightly brushing worn floating particles which float on the surface of the test piece; 6, performing data acquisition, and testing an equivalent sound level value of the average noise level; and 6, checking the data validity. The method is used for testing and evaluating the micro-surfacing mixture noise.

The invention relates to an urban traffic noise monitoring system of intelligent terminal monitoring. The urban traffic noise monitoring system comprises a noise monitoring device, a wireless gateway,a noise data storage server, a noise data processing server, a cloud server and a user client, wherein on a wireless noise measuring node, the noise monitoring device is used for measuring the noisedata of the node, the noise monitoring device is a noise monitor with a WiFi function integrating a frequency spectrum analyzer and a sound level meter and an intelligent terminal and is arranged on ageographic position of the wireless noise measuring node, and a specific position in a map is marked by virtue of a coordinate.

A control module, at least a portion of which is adapted to illuminate upon excitation by an energy source, wherein the control module comprises an input port adapted to receive portable audio device signals, an energy source signal, control circuitry configured to measure a first parameter from the audio input. Such a system may be a stand alone module or incorporated with headphones utilizing electroluminescent (EL) display technology, connectable to standard portable audio devices. The assembly may or may not include a display that illuminates using EL capability. Methods of operation are also described.

A sound level monitor device has a microphone. A sound level measurement circuit is coupled to the microphone. The sound level measurement circuit takes sound signals monitored by the microphone and converts the sound signals to digital signals. A display is coupled to the sound level measurement circuit. The display will show the different measurement signal values. A single control button is coupled to the sound level measurement circuit. Pressing the control button a first time activates the sound level measurement circuit so a current measurement signal value is shown on the display. Pressing the single control button a second time causes a highest recorded measurement signal value, since the sound level measuring device has been presently activated, to be shown on the display. The highest recorded measurement signal value remains on the display until a higher recorded measurement signal is monitored. Pressing and holding the single control button for a predetermined time frame deactivates the sound level monitor device.

The invention discloses a digitized acoustic detection system, which comprises a microphone, a front end circuit, an analog-to-digital (A/D) converter, a signal processor, a touch screen and a keyboard. After the microphone converts an acoustic signal into an electric signal, the signal is input into the front end circuit. After the front end circuit amplifies the signal, the electric signal is input into the A/D converter for analog-to-digital conversion. The converted signal is input into the signal processor for signal processing. The touch screen and the keyboard are connected with the signal processor. A calibration module, a sound level measuring module, a spectrum analysis module and a fast Fourier transform (FFT) analysis module are arranged in the signal processor, wherein the calibration module is used for channel calibration and microphone calibration; the sound level measuring module supports A, C and Z frequency weighting; the spectrum analysis module is used for conducting real-time measurement by using 1/1 and 1/3 octave frequency bands within an allowable wide frequency range; and the FFT analysis module is used for measuring the transient sound level, the maximum sound level and the minimum sound level of the selected frequency range. The digitized acoustic detection system has the advantages that the basic detection of various sound levels and sound intensity calculation can be realized, the real-time spectrum and statistical analysis can be conducted to sound vibration signals, the sound vibration signals can be automatically monitored, the data redundancy of low-frequency parts is reduced and the spectrum leakage is reduced through windowing.

The invention discloses a landmine multi-modal vibration mode measurement device and method. The landmine multi-modal vibration mode measurement device comprises a signal generator, a sound emission unit, a sound level meter, a laser Doppler vibrometer, a multi-channel data acquisition card, a computer and a caisson, wherein the signal generator is connected with the sound emission unit through a data line; the sound level meter and the laser Doppler vibrometer are sequentially connected with the multi-channel data acquisition card and the computer through data lines; high-intensity and low-frequency sound waves with continuous sweep frequency are emitted out through the signal generator and the sound emission unit, the sound level meter and the laser Doppler vibrometer detect the sound pressure level of the upper end face of a landmine and an amplitude-frequency characteristic curve of the vibration speed respectively, and the multi-order inherent frequency of the landmine is measured out; the signal generator and the sound emission unit emit high-intensity sound wave signals with the inherent frequency of the landmine as the output frequency, and the laser Doppler vibrometer, the multi-channel data acquisition card and the computer detect, display and record a multi-modal vibration mode of the landmine. The landmine multi-modal vibration mode measurement device and method achieve non-contact type rapid and accurate measurement of the multi-modal vibration mode of the landmine.

The invention relates to a method for evaluating the sound insulation performance of a vehicle body side cavity block. The method comprises the following steps: 1) setting up a reverberation chamber and a full anechoic chamber, separated by a sound-absorbing cotton wall and creating a connection channel on the sound-absorbing cotton wall; 2) arranging inside the connection channel a square projection shaped cavity channel; 3) arranging a sound-absorbing baffle plate on the end face at one side of the connection channel near the reverberation chamber; embedding a to-be-tested block into the boss arranged in the cavity channel; 4) setting up a first measurement point inside the reverberation chamber and a second measurement point inside the cavity channel; and arranging sound-level meters at the first measuring point and the second measuring point respectively; 5) obtaining the SPL1 inside the reverberation chamber and the SPL2 of the connection channel after the connection channel passes the block through the sound level meters at the power measurement positions; and 6) utilizing the difference between the SPL1 inside the reverberation chamber and the SPL2 of the connection channel after the connection channel passes the block as the sound insulation performance grade evaluation value for the to-be-tested block. Compared with the prior art, the method of the invention can measure individually and is suitable for different shapes.

The invention discloses a detection device for the ripeness degree of watermelons and pesticide residue. The detection device comprises a conveyor belt, a base plate, a spring, an elastic baffle plate, a connecting plate, a motor, universal wheels, an operation platform, a first detection box, a far infrared light source, a metal ball, an electromagnet, a temperature sensor, a sound level meter, an optical fiber detector, a computer, a single chip microcomputer, a voice signal acquisition card, a spectrograph, a second detection box, a detection needle, an enzyme electrode sensor, a first hydraulic retractable rod, a hydraulic cylinder, a pneumatic sliding rail, a sliding block, a second hydraulic retractable rod, a third hydraulic retractable rod, a fixed claw and an air cylinder. According to the detection device disclosed by the invention, indexes including the sugar content, acidity, solid-state dissolved matters and the like of the watermelons are detected by adopting a far infrared manner, so that the ripeness degree of the watermelons is determined; in a detection process, the elastic baffle plate is used for fixing and is suitable for fixing the watermelons with different sizes; meanwhile, the metal ball is used for carrying out dual detection in a knocking manner and the accuracy and reliability of the ripeness degree of the detected watermelons are ensured.

The invention relates to a wireless monitoring urban traffic noise inquiring system. The wireless monitoring urban traffic noise inquiring system comprises a noise monitoring device, a wireless gateway, a noise data storage server, a noise data processing server, a cloud server and a user client, wherein at a wireless noise measuring node, the noise monitoring device is used for measuring the noise data at the node, the noise monitoring device is a noise monitor with a WiFi function integrating a frequency spectrum analyzer and a sound level meter, and is arranged on a geographical position ofthe wireless noise measuring node, and a specific position of the noise monitoring device is marked in a map by virtue of a coordinate.

An on - line noise test method of product includes setting semi - soundproof room on product conveying belt and setting sound level meter in the semi - soundproof room, then applying equivalent test relation listed in national standard to judge whether noise project is qualified or not. The method is suitable to be used on production line of electromechanical products in small size.

A method and apparatus for examining a subject for a particular physiological condition according to a technique which utilizes sounds generated by the subject and sensed at a predefined distance from the site of sound generation of the subject, by locating a first sound sensor, e.g., a sound level meter which measures the sound levels in decibels, on a particular region of the subject's body to produce an output corresponding to the sound level sensed thereby; modifying the output of the first sound level meter by a pre-calculated Transfer Function equating its output to that of a second sound level meter located at a predefined distance from the site of sound generation of the subject's body; and utilizing the modified output of the first sound level meter in determining the existence of the particular physiological condition.

The invention discloses a method for while-drilling detection of the roadway roof rock Protodyakonov coefficient based on a sound level meter. In order to solve the problem of while-drilling detection of the Protodyakonov coefficient, namely an important rock mechanical index influencing a coal mine roadway roof anchorage supporting scheme, a roadway roof is drilled to form drill holes with the diameter being 32-42 mm; a bearing type while-drilling device loaded with a sound lever meter probe is installed on the rear portion of a drill bit; through combination with reading of a scale drill stem, the volume decibel values of the drill holes with different depths are tested in the drilling process; and based on the rock Protodyakonov coefficient (namely from 0.3 to 20) standard library established in a laboratory, the rock Protodyakonov coefficient in the roadway roof drilling range is obtained quickly by comparing the volume values with roadway in-situ rock drilling volume decibel values, harmful noise in the drilling process is converted into a favorable sound source, and the technology of while-drilling detection is achieved. The method is suitable for while-drilling detection of the Protodyakonov coefficients of typical sedimentary beds, including sandstone, shale and mudstone, of coal measure strata. The method has the advantages of being conveniently applied in site, being easy to implement and low in labor intensity, and not influencing normal production.

Single-frequency tone acoustic signals are main types in environmental noise. The invention discloses a single-frequency tone acoustic signal automatic monitoring method for environmental noise, and high-accuracy fitting is realized between physical characterization and human auditory characteristics. According to the invention, the real-time acquisition, mathematical description and physical characterization of single-frequency tone acoustic signals are gathered in the method. According to the invention, the A-weighted sound level core algorithm in environmental noise monitoring is improved, a polynomial single-frequency noise correction factor mathematical description relationship in which a logarithmic function is added with a trigonometric function is provided, undetermined coefficient and initial phase angle parameter optimization in the mathematical description relationship can be realized, and through the high-accuracy fitting experimental tests on 40phon equal loudness curves, the fitting absolute error is less than 0.15dB, and a same change rule is found for different- loudness equal loudness curves. The measuring error of a precision sound level meter is about +/-1dB, and the measuring error of an ordinary sound level meter is about +/-3dB. The measuring error of the method adopted in the invention is less than 0.15dB, and the accuracy fully meets the requirements. At present, similar technologies has not yet found.

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.