spread spectrum modulation 中文意思是什麼

spread spectrum modulation 解釋
擴展頻譜調制
  • 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...
  • spectrum : n. （pl. -tra ）1. 【物理學】譜，光譜；波譜；能譜，質譜。2. 【無線電】射頻頻譜；無線電（信號）頻譜。3. 【心理學】（眼睛的）余像；殘像。4. 〈轉義〉范圍，幅度；（連續的）系列。
  • modulation : n 調整，調節；（聲調的）抑揚，變化；【音樂】轉調，變調；【無線電】調制。 amplitude modulation 振...
  1. Spread spectrum modulation ssm

    擴頻調制
  2. The manner of modulation, the spread spectrum codes, and the manner of the acquisition and tracking are discussed. barker codes, dpsk and match filter with the ability of rapid acquisition are concluded as the appropriate manner for cdma missile controlling and guiding

    對擴頻碼、調制解調方式、捕獲與跟蹤方式進行討論，得出barker碼、 dpsk 、匹配濾波器快速捕獲是適合便攜式反坦克導彈cdma無線制導的相應工作方式。
  3. The wireless channel based on spread spectrum modulation can assure the digital video signal communication safe and withstanding the high noise disturbing condition

    而基於擴頻技術的無線通信通道，為視頻的傳輸提供了保密及抗干擾性能強等優點。
  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. This paper presented a general systematic view, application and current development of the power line carrier transmission technology, and clearly compared some existing power line carrier communication chip with each other. then the authors analyze the channel " s characters of low voltage power line, and formed an abstract carrier channel model. using this as its basis, a new kind of transmission technology is designed that adopted transmission technology combining the spread spectrum modulation with channel coding, which can solve the problems above mentioned to a certain degree, and need not pay for high cost

    文章不僅全面地介紹了電力線載波通訊技術的特點、應用及其發展狀況，還對目前的電力線載波通訊晶元進行了比較；並通過對低壓電網通道特性的分析和研究，抽象出其載波通道模型，在此基礎上，提出了將擴頻調制和通道編碼相結合的傳輸技術用於低壓電力線載波通信，這可以在很大程度上解決電力線的干擾問題，且不必付出高昂的代價。
  6. 4. analyzed two types of spread spectrum ( dsss and fhss ) approved by the fcc based on the characteristic of phy layer ; then analyzed the characteristic and technology of the cck modulation and at last put forward an improved cck scheme that will increase the data rate of wlan to 16. 5mbps

    針對物理層的特點，討論了無線局域網的兩種擴頻技術? ? dsss和fhss ，分析比較了兩者的性能特點和適用的范圍，並探討了一種支持高數據數率的cck調制方式以及使速率能達到16 . 5mbps的cck改進方案； 5
  7. The second part studies the characteristics of cdma2000 1x reverse link, and implements a softcore design of the cdma20001x rtl soc with hdl ( hardwire desciptionin language ) verilog in accordance with the is - 2000 specifications. the model include the softcore of a spread spectrum modulation and a simple 8 - bit processor. as the same time simulate all the parts of the soc softcore with software modesim

    ，本文的第二部分認真的研究了cdma20001x的反向鏈路的特點，設計反向鏈路的擴頻調製片上系統方案。用硬體語言verilog設計cdma20001x的擴頻調製片上系統的ip軟核。其中包括擴頻調制部分和一個8位的cpu設計。
  8. Cck, dqpsk are concluded as the best spread spectrum / modulation techniques in wireless image communication systems. 1 imbps and 300 meter range can be obtained using orinoco wireless network card based on eee802. 11b wlans, which specifies cck, dbpsk, dqpsk techniques

    這種網卡採用直序擴頻和cck 、 dbpsk 、 dqpsk調制方式，工作在2 . 4ghz頻段，數據傳輸速率為11mbps ，傳輸距離最遠達300米。
  9. 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。
  10. Secondly, we apply tk operator to the cross - correlation of received signal code and pn code to separate the multi - paths. it comes to a conclusion that tk operator can separate the multi - paths within less than the chip period accurately of spread - spectrum system with space - modulation by simulation. at last, we apply this algorithm to the practical signal collected by gps tap, and from the result we can drop a conclusion the tk algorithm is practical

    本文首先闡述了時空調制擴頻信號原理以及在多徑干擾下時空調制接收機的性能和teager - kaiser接收機的原理;接著對時空調制擴頻系統的解調信號與偽碼的互相關函數採用tk接收機進行多徑分離，模擬結果表明， tk接收機對時延在一個碼片內的時空調制擴頻通信多徑信號有很好的分離效果;最後用數據採集器對一個gps信號進行接收和多徑的估計，驗證了該演算法在實際的運用中對多徑的擴頻信號有很好的分離效果。
  11. The general requirement of communication system and the application potential in secure communication are expatiated. the chaotic secure communication methods home and abroad are also summarized, including chaos spread spectrum communication, chaos key - shifting, chaos parameter modulation, chaos masking, chaos cdma. the exiting problems and development direction are also pointed out respectively

    介紹了混沌學的發展過程和意義，闡述了通信系統的一般要求和混沌在保密通信中的應用潛力，綜述了國內外現有的混沌保密通信方法，其中包括：混沌擴頻通信，混沌鍵控，混沌參數調制，混沌掩蓋，混沌數字碼分多址等五大類，指出了各自存在的問題和發展方向。
  12. A new spread - spectrum system with four phases space - time modulation for direction - finding and ranging

    一種新型同時測向測距四相時空調制擴頻系統
  13. In chapter 4, the spread spectrum modulation sequence performance is discussed on the base of the multiple address selected ability and secret communication

    在第四章中，在基於多址選擇能力和保密通信的基礎上對擴頻調制序列性能進行了討論。
  14. The system include collecting and gathering part. power energy is collected and stored by outer circuit, modulation and demodulation is finished by spread spectrum integrated circuit. the whole system is controled by the window which is designe d by software visual basic

    該系統主要包括採集器和集中器，由外圍電路完成電量的採集和存儲，由擴頻晶元對信號進行調制和解調，通過電力線的傳輸，實現對電量的抄送，通過visualbasic設計的通信界面實現對系統的控制。
  15. And what we do in this paper is to put forward an effective algorithm to estimate the sub - chip multi - path component of spread - spectrum positioning system with space - modulation and put it into practice

    為此，本文針對時空調制擴頻定位系統給出一種有效的碼片內多徑估計的演算法，並用gps擴頻系統的多徑信號進行多徑估計驗證。
  16. A kind of secure communication system scheme is presented, which utilizes vss synchronizing controller to demodulate. amplitude masking modulation and spread spectrum modulation are considered to validate feasibility of the presented scheme

    在此基礎上，提出了一種基於變結構混沌同步的保密通信系統模型，該模型把一個混沌系統作為加密調制器，其變結構同步控制系統作為解調器。
  17. An asymmetric digital watermarking algorithm based on dwt is presented in this paper. the watermark was embedded into the middle _ high coefficients based on spread spectrum modulation scheme, and the intensity of embedding could be accommodated adaptively, so the digital watermarking system has good perceptual invisibility and robustness

    該演算法利用私鑰把水印嵌入到小波分解后的中高頻系數中，提高了水印系統的不可視性，水印嵌入過程中可以自適應的調節嵌入強度，同時引入了擴頻的概念，增強了水印系統的魯棒性。
  18. Simulation results demonstrate theoretical derivation is correct and both sequences can be used in communication. based on the presented ds / sfh communication scheme, and employing msk as fh spread spectrum modulation, the performance is studied n the presence of partial band multitone jamming and additive white gaussian noise ( awgn )

    根據所提出的混合ds sfh擴頻通信系統方案，採用msk相干調制，在假設直接序列擴頻后信號帶寬等於跳頻間隔的情況下，推導了系統在部分頻帶多頻干擾和加性白噪聲下的誤比特率公式。
  19. This chapter is a base of next chapter. mathematics theory and pseudo stochastic code theory for spread spectrum modulation sequence are introduced, and simulink experiment and analysis about correlation performance of the most common use spectrum modulation sequence are processed, these experiment contact to performance parameters of the spread spectrum sequence. the correlation performance and address quantity are compared between m sequence and gold sequence

    本章是第五章的理論基礎，介紹了擴頻調制序列的數理基礎和偽隨機碼理論，同時聯系調制序列的性能指標對最常用的兩種擴頻調制序列的相關性能進行了模擬研究和分析討論，比較了m序列和gold序列互相關特性和地址數。
  20. A tdrss user transponder is a terminal of the user satellite in this system, in which qpsk or sqpsk modulation and direct sequence spread spectrum ( ds - ss ) are employed in the forward / backward links

    Tdrss用戶應答機是該系統的用戶終端，其正反向鏈路的信號通常採用qpsk或sqpsk調制和直接序列頻譜擴展。
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