expanded noise 中文意思是什麼
expanded noise
解釋
「偽展」噪聲-
Turbo codes represent the new code structures, which consist of pccc ( parallel serially convolutional code ) and sccc ( serially concatenated convolutional code ). in this paper, the background of turbo codes are firstly introduced, which includes the base principle of error correction code 、 block code and convolutional code ; the principle of turbo code and the iterative decoding is secondly expanded ; the key decoding algorithm : a revised map algorithm and iterative decoding theory are detailed ; then, a new turbo code structure : hccc ( hybrid concatenated convolutional code ) is presented, and the capacity of this code method is analyzed, the average capacity upper bound is derived ; at last, this code is simulated on awgn ( additive white gaussian noise ) channel and rayleigh fading channel
本文首先介紹了turbo碼的背景知識，包括差錯控制的基本原理、分組碼和卷積碼；然後闡述了turbo碼的基本原理，包括turbo編譯碼器結構及迭代譯碼原理；較為詳細地描述了關鍵的譯碼演算法： ?種改進的最大后驗概率（ map ）譯碼演算法及迭代譯碼演算法；提出了一種新的turbo碼結構：混合turbo碼（混合級聯卷積碼） ；並用編碼性能聯合界分析方法對混合turbo碼進行了性能分析，得出了其平均性能上界；並在高斯白噪聲通道和瑞利衰落通道上分別作了一些應用研究及計算機模擬實驗。 -
The reason that the noise is lower with inclining tongue is : 1 ) both the radius of the tongue and the gap between the tongue and the blade are changed across the wideth ; 2 ) the phase angle between blade and the tongue is changed across the wideth, therefore the peak value of the noise do not appear at the same time, so the peak value of the noise with inclining tongue is much lower than the straight one. the influence of the expanded angle of the shell of the fan on the noise was invested experimentally, and the optimal angle was got
傾斜蝸舌降噪的主要原因是：一是改變了從氣流入口側到風機輪盤的蝸舌間隙和蝸舌半徑；二是改變了葉輪與蝸舌非定常相互作用的相位差，使其產生噪聲也有相位差，迭加的結果進一步降低了噪聲。另外，試驗研究了不同蝸殼擴張角對風機噪聲及效率的影響規律，蝸殼擴張角選擇當否，對效率和噪聲影響較大。 -
This article qualitative introduced the use tree planting method, during beautified environment, reduces the ships noise to the environment pollution, expanded the tree planting potency
摘要針對船舶噪音與居住環境的矛盾逐漸突出，提出了利用綠化手段，降低船舶噪音對環境的污染，擴展了綠化的效能。
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