direct spread system 中文意思是什麼

direct spread system 解釋
直接頻率擴譜系統
  • direct : adj 1 筆直的，一直線的；正面的。2 直接的。3 直截了當的，直率的，明白的。4 直系的，正統的。5 【語...
  • spread : vt （spread）1 伸開，伸長（手臂等），展開，張開（帆等），打開（地圖等）；鋪開（氈子等），展寬，展...
  • system : n 1 體系，系統；分類法；組織；設備，裝置。2 方式；方法；作業方法。3 制度；主義。4 次序，規律。5 ...
  1. Chapter 4 makes up a modulate and demodulate system based on direct spread msk

    第四章中構建了一個直擴msk調制解調模型。
  2. By 1993 technological breakthroughs we had made allowed us to record 48 neurons spread across five structures that form a rat ' s sensorimotor system ? the brain regions that perceive and use sensory information to direct movements

    到了1993年，由於技術的突破，使我們能夠在形成老鼠的感覺運動系統的五個構造里，同時記錄48個神經元；感覺運動系統是腦中負責感知並利用感覺訊息來引導動作的區域。
  3. Then studies a peculiar multi - carrier direct sequence spread spectrum ( mc - ds - cdma ) technology, analyzes the methods of processing multi - carrier signals and study the mathematical module of multi - carrier communication system receiver

    然後對本文所研究的這種特殊的多載波直接序列擴頻技術進行闡述，分析了多載波信號處理的方法和研究了多載波接收機的數學模型。
  4. 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字調制技術進行分析的基礎上，將通信理論中的直接序列擴頻技術（ dsss ）用於解決低壓電力線通信的干擾問題，主要研究內容如下： （ 1 ）用通信模擬軟體systemview對dsss技術的通信和抗干擾原理進行模擬分析，分別對時域和頻域下採用dsss技術前後接收信號的頻譜進行分析，驗證dsss技術在本系統中的可行性； （ 2 ）由dsss技術對濾波系統的要求，根據濾波理論分析了巴特沃思型濾波器的逼近原理並設計了合適的濾波電路； （ 3 ）用調制解調晶元sc1128和自行設計的濾波器加之輔助外圍電路，構造出低壓電力線載波通信系統，並採用atmel公司的單片機設計了接收和發射電路的微控制器； （ 4 ）分別對採取抗干擾措施前後輸入和輸出信號進行對比實驗，並對結果進行分析，驗證了dsss技術對干擾信號的抑制作用。
  5. The parallel combinatorial spread spectrum provides high spectral efficiency and the data rate of the parallel combinatorial spread spectrum is higher than that of the direct sequence spread spectrum. this thesis studies on the mapping between data and spread sequence in the parallel combinatorial spread spectrum system and presents a mapping method based on the lexicographic order. the mapping method resolves the many to one mapping problem of the past method

    本文研究了并行組合擴頻中數據和擴頻序列之間的映射方法，指出了已有的一種不定方程求解演算法中存在的映射不唯一問題，應用組合數學中的相關理論，將映射問題轉化為廠組合問題，提出了基於字典順序的并行組合擴頻數據映射演算法，該演算法具有普遍性，解決了原有演算法中的多一映射問題。
  6. The design of direct sequence spread spectrum communication system for data transmission

    直接序列擴頻數據通信系統的設計
  7. In wcdma system which uses direct sequence to spread spectrum, the spread spectrum code ( pn code ) phase of the receiver must be synchronized with that of the received signal precisely to despread and demodulate the signal correctly. multipath channel exists in the mobile communication environment for the radio signal reflection by obstacles between transmitters and receivers. by using the autocorrelation of the spread sprectrum code, rake receiver can process received signals and therefore multipath components can be resolvable

    在wcdma系統中，為正確解擴解調接收到的擴頻信號，接收機本地產生的擴頻碼（ pn碼）相位必須和接收信號中的擴頻碼相位完全同步;同時移動通信環境中的傳輸信號由於接收機和發射機之間的直達路徑有可能被建築物或其他障礙物所阻礙，總是經過折射或反射的多條路徑后才到達接收機，從而產生多徑通道。
  8. The text message appeal was made using police direct, a system developed by the police information technology organisation after the july 7 london bombings to spread information rapidly

    據報道，在該案破獲中發揮重大作用的「文本式報文」電子信息平臺，是去年7月7日倫敦爆炸案發生以後開設的，用於向簽約公眾快速發布緊急信息。
  9. Coulthard was convicted of burgling churches in 2003, and used lock picks and surgical scissors hidden in an empty camera case he used to disguise himself as a tourist. the text message appeal was made using police direct, a system developed by the police information technology organisation after the july 7 london bombings to spread information rapidly

    據報道，在該案破獲中發揮重大作用的「文本式報文」電子信息平臺，是去年7月7日倫敦爆炸案發生以後開設的，用於向簽約公眾快速發布緊急信息。
  10. The spread spectrum communication ’ s availably jamming becomes the key to get the electronic war ’ s victory, so it is very important to research the effectiveness of jamming and interference referred to the direct sequence spread spectrum ( ds - ss ) communication system

    為取得現代電子戰的勝利，對擴頻通信的有效干擾成為關鍵。因此，研究直接序列擴頻通信干擾效能具有重要的現實意義。
  11. Secondly, this paper analyses data - delivering method, data - transmitting format and fault - control technology, studies and picks out direct sequence spread spectrum, accessing point network topology and the ieee802. 11b network rule, on the basis of which the harbor wireless communication system model is established. each composing part of the system ' s model is given out. the choice of hardware equipments and the design of communication software are expounded

    其次，本文對通信技術中的數據傳送方式、數據傳輸形式和差錯控制技術進行了分析，研究了港口無線通信系統中的傳輸方式、拓撲結構和網路標準等關鍵技術，選取直序擴頻傳輸方式、接入型拓撲結構和ieee802 . 11b網路標準作為港口無線通信系統的技術基礎，建立了港口無線通信系統模型，闡述了該模型的實現方法，包括硬體設備選擇和通信軟體設計。
  12. We analyzed the anti - jam and band inside anti - interfere performance of the system, and the low probability intercept ( lpi ) of the traditional direct sequence spread spectrum ( dsss ) modulations in the uav platform ' s applications. so a new modulation technique using a multi - level pseudo noise ( pn ) code has been presented. the new multi - level pn code is built from a high speed pn code through a low passed filter ( lpf )

    分析了系統抗阻塞式干擾和抗帶內頻帶干擾的性能，以及常規bpsk qpsk - dsss調制在無人機通信中存在的安全隱患，提出了一種用多電平pn碼進行擴頻調制的方法：採用高速pn碼，經過低通濾波器，產生多電平pn碼進行直序擴頻調制，能在低信噪比情況下有效抵抗平方率檢測器對系統載波的檢測。
  13. In addition, hybrid spread - spectrum communication system is propitious to enhance anti - jamming performance of the system that is make up of direct sequence ( ds ) and frequency hopping ( fh ), and it can satisfy the require of anti - jamming of systems. it concentrate their virtue and overcome shortage in single spread spectrum style. this paper discusses the aspect in detail

    另外，將擴頻技術中應用最廣泛的兩項技術直序擴頻（ ds ）和跳頻（ fh ）結合在一起，構成混合擴頻通信系統，有利於提高系統的抗干擾性能，更能滿足系統抗干擾的要求，而且將跳頻系統和直擴系統的優點集中起來，克服了單一擴頻方式的不足。
  14. In this article, we introduce the basic principle of the self - encoded direct spread ( seds ) system, construct the model of the system, and analyze the main performances of the system, such as ber performance, self - interference, mai performance and so on

    本文介紹了自編碼擴頻系統的基本原理，構建了系統模型，並對其主要性能，如誤碼率性能、自干擾特性、多址能力和抗多徑干擾能力等作了分析。
  15. Direct - sequence spread spectrum communication system simulation

    直接序列擴展頻譜通信系統模擬
  16. Then taken four kinds of maps for examples, comparing with m - sequence, their properties are calculated, verifying the advantages of the chaotic sequence generated by the new method. after this, an improved scheme is discussed - - using m - sequence to change the sequence ’ s turn and verifying that the permutation parameters have effect on improving the sequence ’ s properties. in chapter 5, monte carlo simulation method is used to test performances of our sequences ’ applications in the given model of direct spread spectrum cdma system, and results of error rate of the system are given ; the comparing resuls of performances of anti - multi - access interference and anti - multi - address interference of different pn sequence is also shown in this thesis

    本文首先對擴頻通信中常用二進制偽隨機序列的產生方法、性能特點進行了總結，指出了現有二進制偽隨機序列的應用局限性;其次，根據混沌非線性系統特徵，深入研究了混沌數字序列的產生方法;在此基礎上，提出了一種新的產生方法中間抽取法，然後，以四種混沌映射系統為例，對其所產生的混沌數字序列進行了偽隨機特性實驗數據分析，並與m序列進行比較，結果說明了混沌數字序列代替傳統擴頻序列的優點，同時驗證了新方法的可行性。
  17. At last, this thesis use montecarlo simulation method in the given model of direct spread cdma system to calculate the error rate of system which use the every mentioned pn sequences one by one. the simulation tool is matlab

    文中最後採用蒙特卡洛模擬方法對直擴cdma系統模型應用不同偽隨機序列進行擴頻的情況進行了模擬，並計算出了系統的誤碼率，所用模擬工具為matlab 。
  18. Additionally, since direct spread spectrum sequence ( dsss ) signal has an ultra - low power spectrum density, finding approaches to detect it and estimate its parameters in the non - cooperative communication system is a great challenge for applications

    另外， dsss信號由於具有極低的功率譜密度，如何在非協作通信中不知道擴頻序列的前提下對其進行檢測和估計，是一個具有很強應用背景的課題。
  19. This thesis is focoused on the pn sequence of direct spread cdma communication system, including it ' s generation and properties analyzing. at first, this thesis expounds linear - shift - register sequence and chaotic sequence, and calculates the value of their main properties

    本文的研究的是直接序列擴頻的碼分多址（ codedivisionmultipleaccess ，簡稱為： cdma ）通信系統中的偽隨機序列技術，包括它的產生方法和性能分析。
  20. Cdma is a main technique of the third generation wireless personal communication system. it adopts to the method of spread spectrum ( ss ), so the quality of the ss sequence affects the system performances directly. this thesis focused on the chaotic digital sequence of direct spread spectrum cdma communication system, including its generation, characteristics and application properties analyzing

    碼分多址（ codedivisionmultipleaccess ，簡稱cdma ）是第三代無線個人通信系統的一項主要技術，它採用擴頻通信方式，而擴頻序列的好壞直接關繫到擴頻通信系統性能的好壞。
分享友人
分享到 Line

分享到臉書