Spectrum Detection of the Sound from a Fan within a Noisy Environment
碩士 === 國立中央大學 === 機械工程學系 === 102 === The purpose of this research is to establish the measuring equipment, used within an environment with its level similar to an office, which can determine if a fan is in good condition. The company provided the measurement data, in an anechoic chamber, for five...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2014
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| Online Access: | http://ndltd.ncl.edu.tw/handle/72tteh |
| Summary: | 碩士 === 國立中央大學 === 機械工程學系 === 102 === The purpose of this research is to establish the measuring equipment, used within an environment with its level similar to an office, which can determine if a fan is in good condition. The company provided the measurement data, in an anechoic chamber, for five different models of fans. Based on the frequency domain data, one can choose several discrimination indices for examining the Fans. The corresponding critical values of the indices can also be determined.
The goal of designing the equipment is to measure the fan noise in a quiet room and make the decision between fair or foul in a short period. Two microphones were used. One measures the sound from a fan and the other one measures the background noise. The time domain signals then were processed by a LabVIEW program for signal processing. Based on the technique proposed in this research, the processed signal can remove the background noise. Meanwhile, the fan experimental results of the shortened time of measurement would be discussed. All signal processing formulation and the fan discrimination indices were written in a LabVIEW program which shows lights to indicate whether the fans pass the examination. The entire processing time takes about 2-3 seconds plus the measurement time. This equipment can improve the quality of quality control since it distinguishes the sound humans’ ears cannot tell.
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