Agilent 35670內部窗函數對噪聲波形分析的影響

黃勇軍 徐卓華 易文勝
杭州應用聲學研究所,杭州310012
摘　要:頻譜分析設備多具有FFT分析和譜密度分析功能,噪聲測量中發現使用不同窗函數進行FFT分析時,通過頻帶電壓級換算出來的噪聲譜密度與直接測量結果有差異。利用35670動態信號分析儀,對不同窗函數情況下的FFT頻帶電壓級和噪聲譜密度級測量結果進行比較,實驗表明：35670譜密度級測量結果能真實反映輸入信號的能量分布,FFT頻帶電壓級的測量結果則需要進行修正。[著者文摘]

Effect on noise analysis due to windowing function of Agilent 35670Huang Yongjun, Xu Zhuohua, Yi Wensheng Hangzhou Applied Acoustics Research Institute, HangZhou 310012Abstract:Usually, spectral analysis equipments have the functions of FFT analysis and spectral density analysis. When different window functions are applied to FFT analysis in noise measurement, differences are shown that the direct measurement results of the noise spectral density are not same with the one derived from band voltage level. With the 35670- dynamic signal analyzer, the FFT band voltage level is compared with the measurement results of noise spectral density level for different window functions. The experiment shows that the spectral density level results of 35670-analyzer are more accurate to express the energy distribution of input signals and modifications are required when the measurement re- sults of FFT band voltage level are used.[著者文摘]

Key words:windowing function; noise measurement;FFT analysis; spectral density