spectrum division 中文意思是什麼
spectrum division
解釋
頻譜劃分-
To this paper we were carried tentatively on spectrum whitening in prestack, and each section after division scale is processed with spectrum whitening, particularly the composition of high frequency is raised apparently, the signal - noise ratio of high frequency raise. the resolution of whole section is better than stack
本文還嘗試性地在疊前進行譜白化處理，對分尺度后的各個記錄分別進行譜白化，尤其是高頻成分提高得很明顯，有效地提高了高頻信噪比，整個剖面的解析度明顯增強。 -
Doing the further research on the division frequency stack on the foundation of study of predecessor, at first the residual moveout correction is done to the seismic record, make the phase axle regularity, doing foundation for the same phase stack ; then carried on division scale processing by wavelet transform ; spectrum whitening is done to each scale, the high and low frequency band need to do prolongs, the middle frequency bands only increase the value of the frequency spectrum ; several kinds of methods that estimate the value of signal - noise ratio has been studied further, and summarize their advantage and disadvantage as well as the scope of application ; the seismic record after spectrum whitening is stacked by weighting with the value of the signal - noise ratio ; then estimate the value of signal - noise ratio which is each scale section after stacking, the scale that the signal - noise ratio is big is assigned big weighting, otherwise, the scale that signal - noise ratio value is small is assigned small weight ing, and carried on weighted reconstruct to each scale section
本文在前人研究的基礎上，在分頻疊加方面做了進一步的研究。首先對地震記錄進行剩餘時差校正，校齊同相軸，為同相疊加做好基礎工作；然後對地震記錄用小波變換的方法進行分尺度處理；對各個尺度分別做譜白化，對于高、低頻段需要做頻帶延拓，中間頻段僅提升頻譜值；對于幾種信噪比定量估計的方法進行了深入的研究，並且總結了它們的優缺點以及適用范圍；對譜白化后的地震記錄用信噪比估計值作為加權系數進行加權疊加；對于各尺度的疊加剖面也進行信噪比估計，對于信噪比大的尺度給予大的加權系數，反之，信噪比值小的尺度給予小的加權系數，對各尺度疊加剖面進行加權重構。 -
Some novel technologies are also proposed, such as two dimensional spread spectrum ( 2d - ss ), self - encoded spread spectrum ( sess ), multiple input multiple output ( mimo ), orthogonal frequency division multiplexing ( ofdm ) and so on
另外，對目前新興的一些抗干擾技術，如二維擴頻、超寬帶、多天線、自編碼擴頻等技術也做了簡單分析。 -
Frequency - domain equalization. at the same time discusses some key problems in ofdm : high ratio of peak - to - average power of output signals, problem of synchronization, channel estimation, adaptive bit, power and subcarrier allocation. emphasize on channel estimation, and present a new algorithm which can filtering more interpolation errors and noise. for the sake of improve the performance of resist narrowband noise and make efficient use of the spectrum apply malvar wavelet division
同時就ofdm系統中的一些關鍵問題如峰值平均功率比（ papr ）太高，同步問題，通道估計，通道、比特與功率必須動態分配進行了研究，著重研究了通道估計問題並提出一種改進的方法，能濾除更多的噪聲分量和插值誤差，提高系統的性能；為了提高抗窄帶噪聲的性能和提高通道利用率，用malvar小波變換實現了不等帶寬分配。 -
Raman fiber amplifier （ rfa ） is a kind of optical amplifier that can amplify signal light directly through nonlinear interaction of high intensity pump and signal light in fiber. whereas the spectrum of raman gain coefficient of optical fiber is not flat, the gain of signal light with different wavelength induced by a single pump is rather different, when wavelength division multiplexing ( wdm ) signal light is amplified by a single pump, the gain spectrum of the wdm signal light is not flat. the flatness of the wdm signal light has important impact on the optical signal - to - noise ratio ( osnr )
拉曼光纖放大器（ ramanfiberamplifier ，簡稱rfa ）利用高強度的泵浦光與信號光在光纖中的非線性相互作用實現信號光的直接放大，但是由於光纖的拉曼增益系數譜很不平坦，所以同一泵浦光源對不同波長信號光的增益就存在很大的差別，因此，用單泵浦光源來放大波分復用（ wavelengthdivisionmulti - plexing ，簡稱wdm ）信號光時，各信號光的增益值就有很大差異， wdm信號增益的平坦度對光信噪比（ opticalsignal - noiseratio ，簡稱osnr ）有重要影響。 -
The technology of direct sequence spread spectrum / code division multipul access ( dsss / cdma ) are applied in the broadband code division multiplex wireless communication systems, which means transmitting data at the rate of 2. 048mbps using four e1 lines within the band of 20mhz. in this paper, the theory of the whole debice is first analysized specified for the system asic design and optimizing its performance
寬帶碼分復用無線傳輸系統是採用直接序列擴頻/碼分多址（ dsss / cdma ）技術，在20mhz頻帶內實現四路2 . 048mbps的e1鏈路數據速率的無線傳輸。本文首先分析了整個數傳設備實現原理，針對系統asic設計和優化整機集成性能出發，提出並實現了基於fpga控制pm4314e1晶元的介面模塊完成對e1鏈路信號的監控和告警功能的改進方案。 -
The main purposes and contributions of this thesis are following : 1. after choosing the pump laser, the optical isolator, the wavelength division multiplexing ( wdm ), the erbium - doped fiber and the edsfs structure, the original edsfs spectrum could be measured. 2
本文的主要工作包括以下幾部分: 1 .按照光源要求達到的主要技術指標，選擇泵浦激光器，光隔離器，光波分復用器，選擇摻鉺光纖類型及長度;選擇光源結構之後，組裝並測試得到原始光edsfs模塊增益譜線。 -
Direct sequence spread spectrum ( ds ) signals have been widely used for secure communication and mobile communication known as code division multiple access ( cdma ) system. because ds signals have many advantages such as anti - jamming capability, low probability of interception, multiple access capability and so on
直接序列擴頻通信具有低截獲概率，抗干擾能力強以及實現碼分多址等優點，因而在抗干擾通信及民用移動通信中得到廣泛的應用。 -
Civil air defense alarm system was a system to dispense antiaircraft alarm sig - nal, hand hostile air attack informational communication to urbanite at wartime. it is a particular informational communication system of the civil air defense depart - ment, and can not be taken place. at the development trend of digitaliza - tion, unitization, integration of civil air defense communication, the civil air defense alarm system is developing too, for adaptation to the require of both future war and peaceful dual, and enhancing civil air defense communication system ' s directing automation. in recent years, development of different kinds of communication technology infuses new clearly energy into communication, especially spread spectrum communication, because of its strongly interference - free feature, invisibility best, realizable code division multiple access and antimultipath wane and so on merit, gets extensive use at wireless region ; the corresponding spread spectrum chips emerge as the times and get boom, which provides advantag e to realization of the circuit of spread spectrum communication. at the same time, in company with the advance of electronics level, the single chip microcomputer has a great development, world renowned chip manufacturer pushout respective products one after another, the kinds of which are too many to statiste
在人防通信的數字化、一體化、綜合化必然的發展趨勢下，人防警報系統也不斷發展，以適應未來戰爭和和平時期的雙重需要，提高人防通信系統指揮自動化。近年來，各種通信技術的發展給通信注入了活力，擴頻通信更因其抗干擾能力強、隱蔽性好、可實現碼分多址和抗多徑衰落等優點在無線領域得到了廣泛應用；其相應擴頻處理晶元應運而生並得到迅速發展，這為擴頻通信的電路實現提供便利。同時隨著微電子工藝水平的提高，單片微型計算機有了飛躍發展，世界上著名的集成電路晶元製造商紛紛推出各自的產品，單片機型號之多，已達到難以統計的地步。 -
Spread spectrum communication takes an important part in military communication and in civil communication. especially in recent years, code - division multiple access ( cdma ) system based on spread spectrum communication is widely used in mobile communication
擴頻通信在軍事通信和民用通信中都具有重要的意義，特別是近幾年來，以擴頻通信為基礎的cdma通信系統在移動通信中得以廣泛應用。 -
Spread spectrum technique, which can handle variable adverse environments, exhibits unique qualities that have a number of advantages in anti - jamming, anti - noise, reduction of multi - path interference, low power spectral density, privacy, selective addressing and code division multiplexing
擴頻通信技術具有優越的抗干擾、抗噪音、抗多徑衰落性能，能在低功率譜密度下工作，具保密性、可多址復用和任意選址，能有效克服各種惡劣的通道特性，目前廣泛應用於移動通信、雷達、導航、測距、電力線通信等領域。 -
And the orthogonal frequency division multiplexing ( ofdm ) is given more and more attention in wireless area, because ofdm lessens the severe effects of frequency selective fading and improves the spectrum efficiency, and this technology has been indicated to become a key technology in the fourth moving communication
其中ieee802 . 11a協議中使用到的ofdm （正交頻分復用）技術，由於其先天具有抗多徑衰落及頻譜使用率高等特性，成為當代無線通信領域研究的熱點，並預示著為第四代移動通信的關鍵技術。 -
Future wireless communication systems trend to provide multi - services to mobile users. cdma technique is adopted by the 3rd generation mobile communication systems due to its flexibility in supporting multi - services. how to keep qos of heterogeneous services and utilize the scarce radio spectrum resources is challenging for 3rd generation mobile communication systems in this thesis we developed a radio resource allocation framework for wireless code division access ( cdma ) networks that support multi - class traffic with different data rates and bit error rate requirements. we proposed a new resource allocation scheme using joint adaptive power control and mmse multiuser receiver in multipath fading system
為移動用戶提供多種業務服務是未來無線通信網路的主要發展方向。由於cdma技術具有靈活支持多種業務的優點，因而被第三代移動通信系統所采納。如何在惡劣的無線傳播環境里以及用戶運動且相互干擾的情況下為為各類業務提供qos保證，同時充分利用珍貴的無線頻譜資源，是基於cdma技術的第三代蜂窩通信系統必須致力解決的問題。 -
Multicarrier wireless communications have been widely investigated in the past decades. recently, two - dimensional spread spectrum ( 2d - ss ) system has drawn a lot of attention because of its full utilization of spreading characteristics in the frequency domain and time domain. compared with multicarrier code division multiplex access ( mc - cdma ), 2d - ss system can effectively mitigate multiple access interference ( mai ) due to spreading in the time domain
當前多載波無線通信技術得到了廣泛的研究，二維擴頻通信系統是近年來提出的新的擴頻通信方式，由於二維擴頻系統從時域和頻域上分別對數據信號進行頻譜擴展，因此它同時具有時域擴頻和頻率擴頻通信系統的特點，是對傳統的一維時域直接序列擴頻和多載波擴頻的推廣。 -
Spread spectrum code division multiple access technique ( ss - cdma ) has successfully been applied in the second generation mobile communication system, such as is - 95. moreover, the main technique of the third generation mobile communication system is also based on cdma
擴頻碼分多址已成功地應用於第二代移動通信中，如is - 95 ，而且第三代移動通信的主要方案也都是基於碼分多址cdma ，因此cdma技術具有無可爭辯的競爭力。
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