نتایج جستجو برای: frequency noise
تعداد نتایج: 648515 فیلتر نتایج به سال:
In this paper, an ultra-low-noise amplifier with frequency band switching capability is designed, simulated and fabricated. The two frequency ranges of this amplifier consist of the 2.4 to 2.5 GHz and 3.1 GHz to 3.15 GHz frequency bands. The designed amplifier has a noise figure of less than 1dB, a minimum gain of 23 dB and a VSWR of less than 2 in the whole frequency band. The design process s...
This study has been carried out in two shoe-making factories in Tehran with the aim ofevaluating the cobined effects of noise and toluene on the workers' hearing. Sixty four workers were assigned to three groups according to their exposure to noise andtoluene. 33 were exposed to noise (group 0), 5 to toluene (group 1) and 26 to noise andtoluene (group 2).The concentration were measured in the ...
Background and aims Overexposure to industrial noise pollution induce hearing loss workers. Occupational hearing loss may cause interference whit oral communication, so it may increase the risk of occupational accidents in workplace as well as affects whit social activities. This study was conducted on Lavan Island, are of oil extracting regions in the south of Iran. The object of this s...
background: noise pollution is currently a major health risk factor for workers in industries. the aim of this study was to investigate noise pollution and implement a control intervention plan for blast furnace in a steel industry. methods: the measurement of sound pressure level (spl) along with frequency analysis was done with the sound-level-meter cell-450 . personal noise exposure was perf...
The output data from a structure is the building block for output-only modal analysis. The structure response in the output data, however, is usually contaminated with noise. Naturally, the success of output-only methods in determining the modal parameters of a structure depends on noise level. In this paper, the possibility and accuracy of identifying the modal parameters of a simply supported...
In addition to farm operations, power tillers in Iran are also engaged in load and passenger transportation. Inspite of their noise and adverse effects on power tiller drivers and bystanders, they have not been adequatly investigated. The initial survey in the present investigation on a 13-hp power tiller at 2200 rpm engine speed revealed that its noise was 92 dB(A), compared to the standard l...
This Letter presents a measurement of the spectral content of frequency shifted pulses generated by a lightwave synthesized frequency sweeper. We found that each pulse is shifted in frequency with very high accuracy. We also discovered that noise originating from light leaking through the acousto- optical modulators and forward propagating Brillouin scattering appear in the spectrum.
The aim of this paper is robust identification of smart foam, as an electroacoustic transducer, considering unmodeled dynamics due to nonlinearities in behaviour at low frequencies and measurement noise at high frequencies as existent uncertainties. Set membership estimation combined with model error modelling technique is used where the approach is based on worst case scenario with unknown but...
Introduction: Although noise characteristics such as intensity and frequency are the main cause of detrimental effects, it is important to pay attention to the personality traits of individuals as the host of adverse health effects. The aim of this study was to investigate the effect of personality traits on sensitivity, annoyance and loudness perception due to exposure to high frequency sound....
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