| Now the noise pollution has been one big environment problem that is concerned popularly. The analysis and control on noise relates to the environment protection, the quality of life and health of body and mind, the competition ability of industry products, the quality, life, reliability and precision of military products, and even to the explore of the human psychology, physiology secrets. That's why all the countries around the world devote huge manpower, material resources and financial to do the research.As we know, the base of solving noise and vibration lies in the research on sound resource. So the key is to research the sounding mechanism while machines are running, to find out the main and easy to solve sound resources of the equipments, then to control them. Now many people are doing the research on noise. And till now many progress have been made. But most of these researches aim to depress decibel of noise. This only reflects the damnification to human hearing and the effect to normal hearing, can't exactly reflect to which degree the effect of noise on human psychology and physiology goes. Now people care quality of life much more than before. Higher demands on sound quality are put forward. In many situations, sound quality is more important than sound intensity. This forces us to find out the called subjective evaluation index and system, which is based on the auditory characteristic of human ear, to evaluate the quality of sound. Then to provide more concrete criterion for the sound quality control. This research is supported by stress scientific research item "the research on the viewable measurement and analysis system of acoustical holography" from China Ministry of Education, by science and technology item "The research of new detect and control method on the harmony of the noise of gear box" from Chongqing Education bureau. Large amounts of theory researches and corresponding experiments have been made. The research object is the noise of gear wheel. The research route is: characteristic of gear noise and its generating mechanism→Fault Diagnosis(identify main noise resource)→depress noise→characteristic of human auditory→model of the sound quality evaluated. The main research content of this paper is shown in the following:(1)To prepare for the following Fault Diagnosis and subjective evaluation, analysis on the generating mechanism and the special modulating characteristic of noise of gear are done. (2) Based on the analysis of the localization of the demodulation methods now popularly used, corresponding solving or optimizing methods are put forward.(3)Base on the analysis of the localization of the demodulation methods, a new optimizing arithmetic model, the energy operator optimizing arithmetic, is put forward first. This new arithmetic is compared with the classic arithmetic, Hilbert demodulating method, from the precision, sensitivity, anti-jamming, complexion and some other fields by experiments.(4)Based on the analysis of the mechanism of the harmonious of music, that is the more simple the integer ration between the frequency of two voice is the more harmonious they are, the creationary viewpoint that to be more harmonious the transmission ratio of multilevel gear wheel transmission must be assigned averagely is put forward for the first time. At the same time, the viewpoint that during gear wheel transmission to be harmonious the gear wheel axes' frequency should avoid to be 4 HZ is put forward. This provides instructional reference point for the gear wheel transmission chain design.(5)Based on the research of the translating mechanism and feeling mechanism of human ear on sound from physiological acoustics and Psychological Acoustics,the subjective evaluation model based on the auditory characteristic of human ear of sound quality: Sharpness index ——method of center of gravity for energy Based on 1/3 octave is put forward for the first time. And the model is validated through subjective evaluation experiment ——"paired compa...
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