direct spread 中文意思是什麼

direct spread 解釋
直接擴展
  • 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...
  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. A novel communication receiver which uses lapped transform ( lt ) incorporating modified median filter ( mmf ) algorithm is designed for narrow - band interference excision. the lt domain mmf algorithm takes full advantages of the direct sequence spread spectrum signal, as well as the characteristics of lt, performing the transform domain filtering twice. the first filtering locates the position of interference and mitigates most of them. the second filtering is performed in a small neighborhood of the located interference. so lt domain mmf algorithm can completely mitigate the interference without distorting the desired signal. simulation results demonstrate the improved ber performance and increased robustness of our receiver

    本文採用改進的重疊變換域中值濾波演算法進行變換域抗干擾處理.該演算法既考慮到直接序列擴頻信號的特點,同時又利用重疊變換的特性對變換域系數進行了二次濾波.該演算法節省處理時間,並且不需要有關干擾的先驗知識,系統性能不會隨干擾頻率變化而變化,因而是一種很穩健的處理方法
  5. 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。
  6. 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。
  7. It spread easily through direct contact among animals

    它通過動物之間的直接接觸迅速傳播。
  8. In chapter 2, a general digital watermarking frame is presented, including the generation, embedding and detection of watermark. in chapter 3, the concept of watermarking channel is presented, the modes of watermarking channel and image dct coefficients is proposed, the capacity of watermarking channel is evaluated by embedding watermarks to selected still image dct coefficients in direct spread spectrum. in chapter 4, a watermarking algorithms based wavelet multi - resolution is presented, by conjunction with human visual model, it keeps invisibility of watermark in host image and need not original image during detection

    數字水印是一種新的數字媒體保護技術,它是將特定的信息(如版權信息、秘密消息等)嵌入到圖象、語音、視頻等各種數字媒體中,以達到版權保護等目的,同時,這種信息對宿主媒體的影響不足以引起人們的注意且有特定的恢復方法,此信息對非法接收者應該是不可見的,本文主要對數字水印的一般框架,靜止圖象dct系數的理論容量,圖象水印的嵌入和檢測,數字媒體防篡改以及數字水印的攻擊等問題進行了研究,提出了兩個新的水印算演算法。
  9. 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
  10. 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。
  11. Telecommunications - electromagnetic compatibility and radio spectrum matters - electromagnetic compatibility standard for radio equipment and services - part 23 : specific conditions for imt - 2000 cdma direct spread base station radio and ancillary equipment

    電信.電磁兼容性和射頻頻譜管理.無線電設備和業務電磁兼容性標準.第23部分: imt - 2000 cdma直接擴譜基地臺無線電設備和輔助設備的特定條件
  12. 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。
  13. Combining walsh sequence with direct spread spectrum sequence, we can construct hybrid ds - fh spread - spectrum communication mode. this is very important for the mode to have better performance on anti - multiple - access inference and anti - near - far inference

    將walsh函數序列與直接擴頻序列相結合構成的ds - fh混合擴頻通信方式對于系統抗多址干擾和遠近效應具有重要意義。
  14. By analyzing the spectrum feature and correlation feature of walsh sequence, we find that it has the spectrum feature of ds / fh ( direct spread / frequency hopping ) communication mode

    我們分析了walsh函數序列的頻譜特性和相關特性,結果表明,該序列具有ds fh (直擴跳頻)的頻譜特性。
  15. 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 。
  16. 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。
  17. 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。
  18. Utra fdd en electromagnetic compatibility and radio spectrum matters - base stations, repeaters and user equipment for imt - 2000 third - generation cellular networks - part 2 : harmonized en for imt - 2000, cdma direct spread utra fdd covering essential requirements of article 3. 2 of the r tte directive v2. 2. 1

    電磁兼容性和無線電頻譜情況. imt - 2000第三代細胞網路用基站中繼器和用戶設備.第2部分:包括r tte指令3 . 2條款的基本要求的imt - 2000的cdma直接擴展
  19. 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。
  20. Utra fdd en electromagnetic compatibility and radio spectrum matters - base stations, repeaters and user equipment for imt - 2000 third - generation cellular networks - part 3 : harmonized en for imt - 2000, cdma direct spread utra fdd covering essential requirements of article 3. 2 of the r tte directive v. 2. 2. 1

    電磁兼容性和無線電頻譜情況. imt - 2000第三代細胞網路用基站中繼器和用戶設備.第3部分:包括r tte指令3 . 2條款的基本要求的imt - 2000的cdma直接擴展
分享友人