time frequency coding 中文意思是什麼
time frequency coding
解釋
時頻編碼-
On the base of researching the theory of the scheme and analyzing the signal feature, it is obtained that the existence manners and character of distance information in the differential frequency signal. at the same time, a new conclusion is gained that the technology of frequency agility can decrease the constant error of system. it is also to say that frequency agility and frequency modulation fixed - distance fuze has the similar feature to random period frequency modulation fixed - distance fuze. according to the theory of address coding in the hopping - frequency communication, the paper presents the principle of selecting the frequency agility sequence which fit to the radio fuze and constructs the frequency agility sequence family based on the rs codes
在深入研究方案原理和分析信號特徵的基礎上，獲得了該體制引信差頻信號中，距離信息的存在形式和特點，得出了頻率捷變技術的引入降低了系統定距固定誤差這一新的結論，即頻率捷變調頻定距引信在定距性能上具有類似隨機周期調頻定距的特徵。本文引入跳頻通信地址編碼理論，結合無線電引信的具體特徵，提出了適用於無線電引信的頻率捷變序列的選擇原則，並構造了基於rs碼的寬間隔頻率捷變序列族。 -
Therefore, during system design, cascade coding combining reed - solomon codes and convolutional codes is utilized ; in addition, time - direction and frequency - direction interleaves are added to alleviate channel fading
因此在進行系統設計時，採用了rs碼與卷積碼的級聯編碼方案，並同時加入時間交織和頻率交織來對抗通道衰落。 -
Comparing with the system which does not space - time code, space - time coding can obtain transmit diversity and increase channel capacity without frequency bandwidth loss
與空間未編碼系統相比，空時編碼可以在不犧牲帶寬的情況下起到發射分集和提高功率增益的作用。 -
Space - time coding for single - carrier frequency - domain equalization systems
引入空時編碼的單載波頻域均衡系統 -
One is to use fourier transformation to convert the source signal from time domain to frequency domain and to discard high frequency harmonious components upwards of 19 ( gb / t14953 - 93 d5. 3 demanding ), then to have static huffman coding to the quantized char array which is composed of reserved direct current component and basic wave and each high frequency " s amplitudes and angles. the other is to use discrete wavelet transformation to convert the source signal from time domain to frequency domain and to set the high frequency coefficients that its absolute value is smaller than the given threshold to zero, then to have dynamic huffman coding to the quantized char array which is composed of multiple, wavelet ' s level, datum length, low frequency coefficients and reserved high frequency coefficients. mass simulinks and analyses under the two circumstances have done to show that data compression ratio is small and the relative error is also small and within the permission of engineering and the compression problem can be solved in theory of measured datum of power system
第一種情況的壓縮方法為：採用傳統的傅立葉變換把原始信號從時間域變換到頻率域，舍棄20次及其以上的高次諧波成分（保證了gb / t14953 ? 93d5 . 3要求） ，然後對保留的直流分量、基波和各次諧波的幅值和相角數據量化后和量化時分別乘以的倍數系數構成一個數組，以字元形式保存，採用靜態huffman編碼對變換數據進行壓縮；採用離散小波變換把原始信號從時間域變換到頻率域，然後對分解得到的高頻系數進行閾值量化處理，對乘以的倍數系數、小波變換的階數、小波變換后的低頻、各級高頻以及原始數據長度、量化后的低頻系數以及保留的高頻系數大小、位置構成一個數組，以字元形式保存，採用動態huffman編碼對這個文件進行壓縮。 -
A subspace - based blind channel estimator has been developed for space time coding orthogonal frequency division multiplexing ( stc - ofdm ) system with two transmit antennas and two receive antennas
摘要針對使用2個發射天線和2個接收天線並且採用循環前綴的空時編碼正交頻分復用系統（ stc - ofdm ） ，提出了一種通道盲估計演算法，並給出通道可被辨識的條件。 -
Blind signal detection for space - time block coding in frequency - selective scenario with linear pre - coding
頻率選擇性通道下空時分組碼直接盲信號檢測演算法 -
Firstly, it introduces the development of speech coding, along with the significance of the low bit rate speech coding. it also compares the model of traditional dualistic excitation lpc vocoder and the multi - band excitation vocoder, and lucubrates the analytical method of frequency domain and time domain in the parameter extraction of multi - band excitation vocoding. secondly, based on the parameter extraction operation of keynote cycle, it adopts time domain in rough estimate operation of keynote and frequency domain in fine estimate operation of keynote, in according to the immediacy required in practice, to minish operation amount
本文闡述了一種基於fpga的多帶激勵語音編碼器的研究與設計，首先介紹語音編碼研究的發展狀況以及低速率語音編碼研究的意義，接著對比分析了傳統二元激勵lpc聲碼器模型和多帶激勵編碼器模型，並深入研究了多帶激勵語音編碼參數提取的頻域和時域分析法，然後根據實際應用的實時性要求，為了減小運算量，在基音周期參數的提取的演算法實現上，本文採用在時域進行基音粗估運算，在頻域進行基音精細估計運算。 -
In this paper, bit - error rate performance analyses are presented for coded and un - coded frequency hopping m - ary frequency - shift keyed systems under the condition of additive white gaussian noise ( awgn ) and partial band noise jamming and multitone jamming. the use of error - correct codes provide a way to improve the performance of frequency hopping system, particularly the use of reed - solomon code in a fh system under the condition of partial band noise jamming can greatly improve the performance of system. so we provide the way of coding and decoding of rs code in c language. in the end, we offer the simulation of the performance of time diversity fh / 2fsk system over partial band jamming noise channels
第一章為緒論，敘述跳頻通信的發展趨勢，以及基本概念，第二章及第三章介紹提高抗部分頻帶干擾的前向糾錯碼reed - solomon碼的原理和實現方法。第四章研究跳頻通信系統在各種干擾條件下的性能。最後在第五章以fh mfsk系統為例，探討在部分頻帶干擾下的系統性能，並進行計算機模擬，模擬結果表明採用分集技術和各種編碼技術對于系統的性能改善具有明顯的效果。 -
Space - time coding technology is based on multi - elements antenna array and has strong points of both time processing and space processing. it can satisfy the requirements of high data rate transmission in the future radio mobile system without the increase of the transmitting power and the spread of the frequency. and it can greatly improve the quality of communication services and system capacity under fading channels
空時編碼技術是一種利用多天線陣發送和接收的技術，該技術能很好地結合時間處理技術和空間處理技術的特點，能在不增大發射功率和不擴展頻帶的前提下滿足未來無線移動通信對高數據率傳輸的要求，從而全面提高衰落通道的通信質量和通信系統容量。 -
It has been proven that the spread spectrum technologies have good capabilities of overcoming isi in electromagnetic wireless channel. the feasibilities of their applications to underwater acoustic channel have been analyzed, the frequency hopping technology is chosen. instead of using time - frequency diversity, convolutional coding and viterbi decoding are employed to combat signal fading, consequently the bit - rate and bit - error - rate performance of the underwater acoustic voice communication system can be balanced and controlled
由於擴頻技術在抗碼間干擾方面具有優良的特性，因此在分析了各種擴頻技術于本研究應用的可行性之後，確定了跳頻技術作為具體實現方案；在克服幅度衰落方面，選用卷積編碼和維特比譯碼方法來替代原有的分集技術以綜合調節系統的通信速率與誤碼性能，達到差錯可控的目的。 -
Fortunately, lapped transform ( lt ), a classical transform arithmetic, possesses the dct ’ s feature of simple realization and low storing cost, while maintaining dwt ’ s advantage. by analyzing its time lapped transform ( tlt ) and frequency lapped transform ( flt ), this article brings forward a arithmetic which carries the temporal laps and frequent laps at the same time and discusses this time - frequency lapped method ( tflt ) combining with context - based entropy coding
疊式變換（ lt ）兼有餘弦變換（ dct ）實現簡單、存儲開銷小和dwt的優點，文中通過分析已有的時域重疊（ tlt ）和頻域重疊（ flt ）疊式變換，提出一種同時進行時域和頻域重疊的疊式變換演算法（ tflt ） ，並結合上下文熵編碼，討論時頻域重疊式變換演算法。 -
Because using ofdm, a frequency - selective fading channel can be transformed into multiple frequency - flat fading sub - channels, in the coding process, spatial diversity ( due to multiple antennas ) is integrated with frequency diversity ( due to delay spread ), therefore, the proposed code can provide higher diversity gain than space - time code alone
該編碼利用正交頻分復用把頻率選擇性衰落通道變換成平衰落通道的特性，同時引入了基於多天線的空間分集和基於時延擴展的頻率分集，比空時編碼具有更高的分集增益。 -
Space - time block codes ( stbc ) based on orthogonal design has attracts enough attentions in its applications in mimo - ofdm systems for its full diversity exploiting and low coding / decoding complexity. these applications include not only system performance improvement, but also reduction of the peak to average power ratio in mimo - ofdm systems. under these backgrounds, this paper first studies space - time block codes under the single carrier, flat fading situation, discusses the encoding / decoding principle and its performance under different channels. then, the author focused on the performance of space - time codes under time selective and frequency selective channels, uncovered the fundamental cause of how maximum doppler shift and power delay profile influences the performance of space - time codes through deduction and simulation
在上述背景下，本文以單載波，平坦衰落通道下的空時分組碼為切入點，深入分析了其編譯碼原理和在不同通道情況下的性能;以此為基礎，後文展開了對空時分組碼在多載波，時間選擇性和頻率選擇性衰落通道下的性能研究，通過理論推導和充分的模擬，揭示了空時/頻分組碼在時頻選擇性衰落通道中的性能變化的根本原因;在以上對多載波系統中空時分組碼的研究的過程中，作者發現了空時分組碼在降低系統峰平比方面應用的可行性，提出了一種降低峰平比的新方法。 -
This is by two reasons : the first, as the development of military communication technologies, it transit from digital to software implementation, intelligence, broad band implementation and network implementation. many new technologies such as adaptive frequency hopping, burst communication, broadband modulation and complex coding accelerate the research about pertinence algorithms of signal sense and signal processing. the second, three hotspots of modern signal processing - spectrum estimation, high - order statistics ( hos ) and time - frequency analysis theory become more and more consummately and being used in communication jamming and anti - jamming field
應用於軍事通信對抗的信號處理理論發展非常迅速，這得益於兩個方面的動力：其一，軍事通信的技術和手段不斷更新，在數字化的基礎上逐步走向軟體化、智能化、寬帶化和網路化，出現了自適應跳頻、突發通信、寬帶調制和復雜編碼等新的實用技術，推動了具有很強針對性的信號偵測和處理領域的演算法研究；其二，現代信號處理的三大熱點? ?譜估計、高階統計量方法、時頻分析的理論和技術日臻完善，並逐漸應用於通信對抗領域。
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