fading rate 中文意思是什麼
-
As a combination of ofdm with space - time coding technique, mimo - ofdm becomes more and more important in the future wireless communication systems, the mimo - ofdm system can not only effectively enhance the transmission rate and capacity of the wireless communication system but also greatly mitigate the effections of mufti - path fading and interfere
Mimo - ofdm技術將ofdm與空時編碼技術有機的結合在一起，能夠大幅度的提高無線通信系統的通道容量和傳輸效率，並能有效的抵抗多徑衰落、抑制干擾和噪聲。 -
The results show that : nano - nickel powder is not useful for mh electrode during the high rate discharge phase as a conductor or additive ; superfine nickel powder is applicable for the conductor of the negative because of the good performance especially the cyclic stability at 1c rate by using 5 % ( mass percentage ) nickel powder ; the utilization of alloy, specific mass and volume capacity are increased with the decreased particle size of nickel powder in negative, however, the capacity fading rate at 1c discharge rate is also increased, so the capacity and the cyclic stability should be taken into account to make a choice of the particle size
結果表明： mh電極中加入納米鎳粉對負極的大電流放電性能不利。 mh電極中加入超細鎳粉后電極綜合性能好，尤其是1c循環穩定性，其最佳添加量為5wt 。減小鎳粉粒度提高了電極合金利用率、質量比容量、體積比容量，但增大了負極1c容量衰減率，因此鎳粉粒度的選擇應綜合考慮mh電極容量和循環穩定性。 -
And the most advantage of ofdm is that it can convert high - rate data stream into the low - rate and reduce data bandwidth so that multi - path - fading can be transformed into flat fading in wireless circumstance
這種調制技術的最大的好處就是將高速的數據流，變換成并行的低速數據流，減小了數據帶寬，從而可將無線環境中的多徑衰落（頻率選擇性率落）轉換成平坦衰落。 -
Single carrier frequency domain equalization for high data rate transmission systems over frequency selective fading channels
頻率選擇性通道下高速數據傳輸中的單載波頻域均衡技術 -
The future wireless mobile communication systems are expected to provide ubiquitous, high - quality, and high - rate mobile multimedia transmission. however, hostile multipath fading radio conditions give rise to serious inter - symbol interference ( isi ) ; even worse, wireless channel are often time varying, which makes the system more vulnerable and more difficult to track the channel state. orthogonal frequency dvision multiplexing ( ofdm ), which is inherently resistant against isi, has invoked a popular research interest in recent years, and has been a promising candidate technology of the physical layer for future weideband high - date - rate wireless communications. notwithstanding, ofdm is much more vulnerable to errors of both time and frequency synchronization and to that of channel estimation, and how to obtain correct timing and channel estimation efficiently is highly critical to ofdm systems. the dissertation will focus on both of the aspects of ofdm systems mentioned above
但是無線環境的多徑特性造成通信系統中嚴重的符號間干擾，同時無線通道的時變性使得通道特性跟蹤復雜。而正交頻分復用技術（ orthogonalfrequencydivisionmultiplexing ， ofdm ）正是一種解決符號間干擾的有效傳輸手段，因此ofdm技術作為未來寬帶高速率無線通信的物理層候選技術在當前引起了一股研究熱潮。但ofdm系統對定時同步誤差和通道估計誤差非常敏感，如何在ofdm系統中準確快速地實現符號同步和通道估計是至關重要的，本論文將重點針對這兩個問題進行討論。 -
For ikgy and lokgy dosimeters, the fading rate is about 1 % for one year after being stored in low temperature and low relative humidity ( rh < 60 % )
經輻照了1kgy和10kgy的劑量計，在低溫、相對濕度小於60的條件下保存一年，年衰退率約1 。 -
Moisture increases the fading rate, while chemical fumes will change the color balance and eventually ruin the dye images.
潮濕會加速褪色，而化學氣味則會導致彩色平衡的改變，甚至損壞染料影象。 -
Based on in - depth study on the mc - cdma system structure, we proposed a combined power and rate control scheme for wcdma over fading channels
在mc - cdma這種方案中，我們提出了功率控制優先於速率控制的演算法。 -
Abstract : by comparing the channel capacities hetwem orthogonal space - time block coding and multi - antenna array system over rayleigh fading channel, some capacity loss for orthogonal space - time block coding is obtained, which is a function of the code rate, the rank of channel matrix and the number of transmitter and receive antennas, although the system of orthogonal space - time block codes is simple and easy to implemented. if is also shown that there is no capacity loss only if both the code rate and the channel matrix rank are all one
文摘:在研究瑞利衰落條件下正交空時分組編碼通道容量的基礎上，將其與多發送多接收天線系統的通道容量進行了比較.比較結果表明，正交空時分組碼雖編碼簡單，易於實現，但在通道容量方面存在較大的損失，損失的程度與編碼碼率、通道矩陣的秩及收發天線數等因素有關.進一步研究表明只有當編碼碼率和通道矩陣的秩都為1時，才沒有通道容量的損失 -
First of all, the characteristics of different adaptive algorithms and equalizers are theoretically researched. then digital microwave communication system model is build by simulink. based on this model, the convergent behavior and bit error rate performance of three equalizers ( nlms, kalman and rls ) are compared in multi - path fading channel
為了達到這個目的，首先需要從理論上對各種自適應均衡演算法以及自適應均衡器的特性進行深入研究;然後利用simulink建立接近實際環境的數字微波通信系統，在多徑衰減通道環境下比較了三種基帶均衡器（ nlms ， kalman和rls ）的收斂特性以及系統誤碼特性，並比較了nlms基帶均衡器和通帶均衡器的性能。 -
This paper mainly discusses the design principles and chief techniques of a digital accessing system for power - line communication net ( plcn ). the technology of low bit rate speech compression high - speed modem based on plcn adaptive equalization to the channel anti - jamming and anti - fading are applied in this system. so speech tele - control data and tele - protection signals can be transmitted high quality in the band - limited channel
該系統綜合應用了低比特率語音信號壓縮編碼技術、基於電力通信網的高速調制解調技術、信號傳輸的通道自適應均衡技術和抗干擾、抗衰減技術，可在帶限通道中高質量的傳輸語音、遠動數據和遠方保護等信號，具有較高的整體性能。 -
We derived theory for abstraction of bandwidth resource and characterization of system capacity for multi - class fading system. bandwidth resources allocated to a user can be abstracted as effective bandwidth, determined by the user ’ s source data rate and target bit error rate. system capacity can be characterized by a theoretical bound. simulations show that actual system capacity is close to the theoretical bound
為一個用戶所分配的帶寬資源被表示為有效帶寬，用戶對數據速率和比特誤碼率的要求決定了對有效帶寬的要求。利用有效帶寬的概念來描述系統的用戶容量並給出了系統容量的理論界限，進一步地，還得到了系統存在發射功率限制時的容量界限。 -
When transmitting signal is below 500 kbps, increasing the system power can reduce the bit error rate ( ber ) for the signal suffering only flat fading
當碼速率較低時（ 500kbps以下） ，信號受到平坦衰落，增大系統功率可以降低系統誤碼率。 -
But when the bit rate is above 1 mbps, the signal suffers frequency select fading, which causes the serious intersymbol interference ( isi ). increasing the system power can ’ t reduce the ber
但是當碼速率提高到1mbps以上時，信號受到頻率選擇性衰落，碼間干擾嚴重，增大系統功率也不能降低系統誤碼率。 -
In this scheme, power control is primary to the rate control. when the fading channel changes slowly, the transmit data rate will be kept on an appropriate level, and only the power control works to keep up with the channel fading and balance the sir. but when the channel quality is poor, the data rate will be switched down without sacrificing the ber ; otherwise, high data rate was selected
我們提出的方案根據反饋的sir動態改變數據的速率和功率，其中功率控制優先於速率控制，當通道變化緩慢時，數據率保持在一個相對穩定的值上，調節發射功率來維持sir平衡；當功率調節無法彌補通道的衰落時，則通過調節速率來維持sir的平衡。 -
Second, this paper design the simulation scheme of bicm for comparing the performance over fading channel and awgn channel that combine 2 / 3 rate, 4 states punctured convolutional code with 8psk modulation, matching block interleave or random interleave, transform through rayleigh channel or awgn channel and use the way that combine coherent demodulation with viterbi decoding in receiver. design the scheme of bicm _ id that use the iterative decoding technique and the scheme of tcm for compare
為了驗證bicm和bicm _ id在衰落通道和加性高斯白噪聲通道（ awgn ）下的性能，設計了一個2 / 3碼率， 4狀態的鑿孔卷積碼經過塊交織或隨機交織，與8psk調制相結合，在rayleigh通道下或awgn通道下傳輸，接收端採用相干解調與維特比譯碼相結合的bicm方案，在接收端引入迭代反饋譯碼的bicm _ id方案，以及與之相比較的tcm方案。 -
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。 -
Based on the obtained lower bounds on mean squared channel estimation errors, the limits on bit error rate ( ber ) for maximal ratio combining ( mrc ) with gaussian distributed weighting errors on independent and identically distributed ( i. i. d ) fading channels are presented
通過對不同衰落通道多普勒譜的積分，求出了相應的通道估計均方誤差下界的閉合表達式，並在此基礎上得到了分集系統在獨立同分佈的衰落通道中採用最大比合併時的誤碼率下界。 -
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。 -
The measurement further indicates that the fading rate exceeds the median value by a factor of about 7 at 460mc and a factor of about 3. 5 at 4110mc
測量結果進一步表明，衰落率在460兆赫時超過中值約6倍，在4110兆赫時超過中值約2 . 5倍
分享友人