應用小波變換檢測噪聲中的信號畢業(yè)論文(更新版)
【正文】 變換分類號 Application of Wavelet Transform to the Detection of Signals in NoiseWang Shiqing Zhu Feng Sheng Kemin(Inst. of Electromag. Field and Microwave Tech., Southwest Jiaotong University, Chengdu 610031, China)Abstract Signal detection based on wavelet transform is studied, and a concept of multiresolution likelihood ratio is put forward. It is shown that there exist some particular spaces in time domain, in which most of the signal energy is conserved while the noise energy is attenuated sharply. Therefore, based on wavelet transform, and by analyzing the likelihood ratio of the particular spaces in time domain, it can be easily determined that whether or not there are some signals mixed in noise Key words signal analysis。1 傅里葉變換與小波變換 有限能量的信號及其頻譜構(gòu)成一傅里葉變換對其中：代表的傅里葉變換；R=(∞,+∞)?！ 弥?，主要考慮二進小波變換［9］(5)其中ψ∈L1(R)∩L2(R)且滿足：。s(t)為待檢測的確定信號。難以判斷在上面三個區(qū)間信號存在的情況。此外，對應的小波系數(shù)在t=127附近與只有噪聲時也有顯著差異，有一極大值，說明信號在此處存在奇異，于是，可以重構(gòu)信號。 19
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