例句與造句

1. this paper mainly focuses on the noise limiting by means of the direct sequence spread spectrum ( dsss ) and the analysis of the transmission performance of the plc and some digital modulation technology . the contents of the paper is as follows : 1 ) the technical feasibility is proved after simulating noise limiting principle of dsss by means of systemview, the simulation software; 2 ) a kind of band pass filter ( bpf ) is realized according to the requirement of filter and the principle of butterworth approximation, which satisfies the index of performance of dsss . 3 ) the low voltage plc system includes the sc1128, the specific modulation / demodulation ic, the bpf filter and other circuit components, furthermore, the control function of system is realized by means of the personal computer and the microcontroller
   本課題在對低壓電力線的傳輸特性和數(shù)字調(diào)制技術(shù)進行分析的基礎(chǔ)上，將通信理論中的直接序列擴頻技術(shù)(dsss)用于解決低壓電力線通信的干擾問題，主要研究內(nèi)容如下：(1)用通信仿真軟件systemview對dsss技術(shù)的通信和抗干擾原理進行仿真分析，分別對時域和頻域下采用dsss技術(shù)前后接收信號的頻譜進行分析，驗證dsss技術(shù)在本系統(tǒng)中的可行性；(2)由dsss技術(shù)對濾波系統(tǒng)的要求，根據(jù)濾波理論分析了巴特沃思型濾波器的逼近原理并設(shè)計了合適的濾波電路；(3)用調(diào)制解調(diào)芯片sc1128和自行設(shè)計的濾波器加之輔助外圍電路，構(gòu)造出低壓電力線載波通信系統(tǒng)，并采用atmel公司的單片機設(shè)計了接收和發(fā)射電路的微控制器；(4)分別對采取抗干擾措施前后輸入和輸出信號進行對比實驗，并對結(jié)果進行分析，驗證了dsss技術(shù)對干擾信號的抑制作用。
2. It's difficult to find limiting principle in a sentence. 用limiting principle造句挺難的