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The main purpose of this paper is to perform a vibro-acoustic analysis in order to predict acoustic response by Computer-Aided Engineering (CAE) models related to a single phase permanent split capacitor motor noise. The radial magnetic force between stator and rotor is a main excitation source to create deformations of the stator housing, causing vibrations and acoustic noise. These forces are determined...
Partial discharge (PD) can be used to predict insulation failures in power transformers. Accurate detection of particular PD types has a significant role in anticipating forthcoming outages. However, the noise encountered with PD measurements negatively affects the detection accuracy. In this paper, we propose a robust PD detection technique that is immune to noise through efficient frequency domain-based...
This article presents two different methods revealing noise sources at turbo-generators. The first method is based upon an identification of amplitudes in a noise spectrum. The second presented method is based upon ISO standards, but was extended by MATLAB application displaying 3D graphs of recorded values.
A noise analysis is conducted on a DC powered dual diaphragm air pump. Using a sound level meter, data acquisition chassis and a LabVIEW based fast Fourier Transform tool, the acoustic spectrum of the pump operating under nominal conditions is obtained. The majority of the acoustic energy propagating from the pump is within the 20 to 2000 Hertz range, classifying the pump acoustics as low pitched...
Hospital is a place that should be free of acoustic problems. According to previous researches, these acoustic problems are responsible for 20.9% – 26.2% of the ICU patient's recovery process. A research based on soundscape of a hospital was done through objective, subjective and simulation methods. The result has shown that the most perceived loud sound is from the ventilator at 4000 Hz with loudness...
The article describes and compares various digital methods for measurement of short delay between fast analogue signals. A brief characterization of measured signals is given in the first chapter. In the second chapter, there are described various measurement methods. In the third chapter, there are compared various versions of each method and in the last chapter, there are the methods compared one...
The performance of the conventional bearings-only tracking (BOT) from a single passive sensor largely depends on the sensor platform maneuvers. This paper presents a new BOT approach based on fusion from two heterogenous bearings-only sensors residing on the same moving or stationary platform. The two sensors are an ESM/EO with negligible propagation delay and an acoustic sensor with significant propagation...
Vehicle brake will produce several noise during braking process, it will influence the life of automotive components. Meanwhile, the sharp brake noise (screaming) will seriously interfere with people's normal life. Thus, the work of brake noise abnormal sound governance is very important. In this paper, the generation mechanism, features and influencing factors of brake are summarized. The theory...
In active noise control (ANC) system, the injection of white Gaussian noise (WGN) for online feedback path modeling and neutralization (FBPMN) degrades the noise-reduction-performance (NRP). In this paper: (1) a tuning free gain scheduling of WGN is used to improve the NRP of ANC system, and (2) a variable step-size is used to compensate for the decrease in the convergence of FBPMN filter due to gain...
This paper deals with active noise control (ANC) for impulsive noise sources for which the filtered-x least mean square (FxLMS) algorithm becomes unstable. By minimizing the fractional lower order moment, the resulting filtered-x least mean p-power (FxLMP) algorithm has an update vector being computed using sign operator and fractional power of the residual error signal. This results in improved robustness...
This paper presents the method and a special approach to signal processing in acoustic passive radar for retrieving aircraft motion parameters. The algorithm of aircraft position determination based on its acoustic noise measurement is developed. This algorithm makes processing of multiple input signals, which are received from several acoustic aerials with definite number of microphones in each of...
Dysphonia is a qualitative and quantitative alteration of the voice due to a structural or functional modification of one or more organs involved in voice production. Voice disorders are prevalent in certain working categories, particularly those of teachers, singers and actors. It is possible to evaluate the state of health of a voice through the acoustic analysis of the speech signal. This provides...
Local traditional arts people and the city's traditional music preservation society have strongly wanted a technology to accurately score traditional music, especially Tsugaru Shamisen. This music will be preserved as scores, which avoids relying solely on the oral transmission of this music to the young performers. At this time, we have experimentally produced an “Electric Shamisen” equipped with...
It is observed that the difference between a measurable value and a threshold does not involve a straightforward comparison of values, given that such measurement, which can only be an estimation, is expressed as an interval. Consequently, the value has to be considered to possess a clear degree of uncertainty. Such matters are highly relevant to the area of the measurement of relative levels of environmental...
Many techniques, such as parameter extraction techniques are used in ultrasonic signal processing. In this paper, the matching pursuit decomposition (MP) and differential evolution (DE) have been tested for parameters estimation, denoising and compression of ultrasonic echoes. The method is based on the MP algorithm who does the decomposition of the ultrasonic signal into elementary functions (atoms)...
This paper describes the design and implementation of a fully integrated Tx/Rx front-end interface for Doppler Imaging with Piezoelectric Micromachined Ultrasonic Transducer (pMUT). The 4-Level Time Gain Compensation (QL-TGC) readout channel with an integrated biasing bank reduces Rx power with satisfactory noise performance (NF=17) and minimal area. The 65nm CMOS chip occupies 200 × 300 μm and has...
The paper presents the first results of a research aimed at the use of a combined opto-acoustic approach, allowing a large band communication network in a harsh environment like the underwater. The realisation of a special modem, optimised for the highly dense swarm is also presented together with a first realization of an optical transducer suitable for a wireless 3D networking operation.
This paper discusses the problem of passive detection of divers in a shallow water environment. The sound produced due to breathing of the open-circuit divers is prominent in the high frequency range of the data. We formulate a detector to detect the waveforms of a diver's breaths, which occur as periodic bursts of sound. This detector is robust to the presence of other interfering sources. Since...
In this paper, we consider data muling over a network of fixed sensors by employing a mobile Autonomous Underwater Vehicle (AUV). We approach the problem using both acoustic and optical communications together in a multi-modal hybrid network: the most appropriate physical layer is chosen according to the quality of the transmissions that take place over time. We consider three distinct cases of water...
Underwater acoustic vector sensor (AVS) is a passive sensor which can provide bearing information of the acoustic sources at a single point in space. This is achieved by combining three dimensional acceleration or particle velocity with scalar pressure measurement. In this work, we study the problem of bearing tracking of two targets using the measurements of a single AVS. For this problem, we propose...
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