نتایج جستجو برای: acoustic noise measurement
تعداد نتایج: 694467 فیلتر نتایج به سال:
Switched Reluctance (SR) Motor Drive is of great topical interest. It has the potential lo emerge as a viable option for variable speed applications. Though simple in construction, the motor is quite rugged, and has many attractive /eatures like high torque-to-inertia ratio, fault tolerance, and high eficiency. A number of converter topologies are prescribed for driving the motor. However, its ...
To solve the problem of tracking an acoustic source in noise and reverberation environment, a new method is proposed in pursuit of higher accuracy. First, this paper improves the unscented particle filter, which can add the latest measurement information to optimize the proposal distribution. Then, the likelihood function is constructed by calculating the microphone arrays’ output energy in the...
High intensity acoustic radiation occurs when turbulence convects past airframe trailing edges. A mathematical model is developed to predict this acoustic radiation. The model is dependent on the local flow and turbulent statistics above the trailing edge of the flight vehicle airframe. These quantities are dependent on the jet and flight vehicle Mach numbers and jet temperature. A term in the ...
Background and aims: In the steel industry, air blowers used to supply compressed air are considered as sources of annoying noise . This study aims to design an acoustic room chamber in order to control the noise level of the air blower. Methods: Measuring of the noise level along with frequency analysis was performed by using sound level meter, model ofCASELLA-Cell.450 . Dosimetery was per...
As a new approach of blind source separation (BSS), independent component analysis (ICA) has attracted extensive attention of researchers in the field of information processing. In this paper, the basic theory and algorithm of ICA are briefly introduced, and then ICA is used for the preprocessing of engine acoustic signals to identify the engine noise sources. The ICA decomposes the signals int...
To investigate the radiation noise characteristics of a centrifugal pump under various working conditions, a noise measurement system is established; afterwards, the distribution of different points and intervals, as well as the overall level of noise, are studied. The total sound pressure level distribution for different points manifests the dipole and asymmetric directivity characteristics. A...
Competitive audio consumer products require not only cheap signal processing hardware but also low-cost analog equipment and sound transducers. The nonlinear distortions produced by these electro-acoustic transmission systems cannot be described and analyzed by standard methods based on linear systems theory alone. In order to take the nonlinear properties into account, we present a measurement...
Development of the next generation of space flight vehicles has prompted a renewed focus on sound source characterization and near-field propagation modeling. Without advancements in these areas, large uncertainties in vibroacoustic loading estimates on space vehicles and payloads may result in structural designs that are either insufficient or excessive. Improved measurements in an extreme env...
Communication in noisy situations may be extremely stressful for the person located at the near-end side. Since the background noise originates from a natural environment, it cannot be reduced for the listener. Thus, the only possibility to improve this scenario with support of digital signal processing is the insertion of speech enhancement algorithms in the downlink direction of terminals. So...
Results on annealed nickel show that the total number of counts of both magnetic and acoustic Barkhausen signals vary inversely with grain size. In decarburized steels the total number of counts and the amplitude of both Barkhausen signals increase in proportion to grain size. The paper addresses these results in context of grain size, grain‐boundary segregation, and precipitate effect.
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