low frequency channel 中文意思是什麼
low frequency channel
解釋
低頻通道-
The major job is manufactured a transmitter, which has three upmixer channels. its function is to up convert the signals from c - band to ka - band. the input local oscillator is provided by a low frequency crystal oscillator which has a good performance of phase noise, through 512 times multiply to ka band. this sysetem is used in the laboratory as transmitter source of the fuze, for the multidimensional objects in practise, which lead to the complexity of the reflect signal, so the amplitude, frequency and the phase of the transmit signals both have a key role in dealing with the reflection signals. therefore, this system requires for both the coherence of the single channel ’ s amplitude, phase and multi channels
本文的主要工作是應用戶要求製作一具有三發射通道的上變頻系統，可以將c波段的微波信號上變頻到ka波段的毫米波信號。系統的本振輸入基頻由一相位噪聲非常好的低頻率晶振提供，經過512次的倍頻放大至ka波段。本系統作為實驗室中引信的發射源，由於目標反射信號具有時變的多維性，反射信號變得極為復雜，在信號處理時，不僅信號幅值、頻率有決定意義而且相位關系也很有決定意義。 -
Working principle : using the low - voltage high - frequency current rtansform from high - tech molectron, conbne traditional energy - channel theory from china, it gets through the energy - channel of body in a breath stimulate bicelectricity of body for therapy, have efficacy of through but indolence it ` s able to adjust metaboilsm, eliminate subhealth, reforning bone, skin etc, fast supply energy for body, at the same time, you can got beauty, health and happiness
工作原理：採用通過尖端電子集成技術轉化的低壓高頻電流，結合中國傳統的經絡理論，瞬間打通人體經絡，激發人體生物進行治療，以達到「通而不痛」的功效，調整代謝，調動潛在的生命能量，消除亞健康，重整經，骨，皮等器官，快速補充人體生命能量，通經活洛，平衡陰陽，增強體內含氧量，調理臟腑，同時美膚修身，以達到身心健康，美好，快樂的境界！ -
Causes small transmission delay, but computation is complex. the other is called dsova, which does not need to know csi, with low - computation complexity and small transmission delay, and is more suitable in the case when side information is unknown. these two algorithms effectively combine the ofdm technology and the sova algorithm in rayleigh channel, resulting in an efficient sova decoding under frequency - selective channel
另一種是不含通道估計的差分sova演算法（簡稱dsova ） ，該演算法不必知道csi ，計算復雜度低，傳輸時延小，適用於邊沿信息（ sideinformation ， si ）未知的情況，這兩種演算法將ofdm技術和rayleigh通道下的sova譯碼演算法有機的結合起來，很好地實現了頻率選擇通道下的sova譯碼。 -
A new method for realization of multi - channel data acquisition on windows flat form is brought forward in allusion to the feature of hyper - low frequency with water pressure pulsation in hydroelectric sets. and various anti - disturbance solutions are adopted in connection with the detection environment. the device proved to be able to has been meet predetermined requirement by its engineering application
針對水力發電機組水壓脈動超低頻特性，開發出一種在windows平臺上實時多通道數據採集系統，並結合測試現場環境，提出了抗干擾的各種措施.經實際運用，達到了預定要求 -
The emphases of our research works are as follows : under ultra - low temperature ( about 0. 236k ) conditions, how the frequency and power of the saw and the source drain voltage influence the acoustic current ; and the relationship between the source drain current and the split - gate voltage ; and how to find the cut off voltage of the quasi - 1d electron channel ; and also the frequency character of the idt in the saw parts
研究的重點為，在甚低溫（ 0 . 236k ）下，通過實驗研究表面聲波的頻率和功率，源漏偏壓等因素對聲電電流的影響;研究準一維電子通道中不同源漏電流與分裂門負偏壓的關系，以找到分裂門的鉗斷點電壓;以及研究聲表面器件叉指換能器的頻率特性等。 -
Parallel structure of poly - phase decomposition and parallel mixer is applied in the ddc circuit, it solves the bottleneck in mixing and increases the handle speed. the partition of the tuning channel according to the digital mixing sequence, and the ddc by means of decimating first, the low - pass filtering and mixing realize efficiently the down - conversion of the variable carrier frequency band - pass signal. according to the structure of the ddc and the requirement of the frequency
短數據快速測頻演算法的具體實現:使用并行流水線的設計方法，提高了系統的數據吞吐率，在100mhz的系統時鐘下，能夠實時處理400mhz ~ 600mhz速率a / d采樣的數據，在64點采樣， 100mhz系統時鐘情況下，初次測頻佔用時間640ns ，以後每次測頻佔用時間縮短到160ns ，實時地提供多相濾波下變頻所需的載頻位置信息，縮短了接收機的調諧時間。 -
Filter poly - phase decomposition method is adopted in this dissertation. the partition of the tuning channel according to the digital mixing sequence, and the digital down - conversion by means of decimating first, the low - pass filtering and mixing realize efficiently the down - conversion of the variable carrier frequency band - pass signal
本文採用濾波器多相分解方法，按數字混頻序列劃分調諧通道，使用先抽取，后低通濾波，再混頻的數字下變頻結構，高效實現了變載頻帶通信號數字下變頻。 -
Frequency sweep flight technique is used to collect the flight data of a model helicopter near its hover and low speed working condition, window frequency spectrum is combined to obtain the frequency response of both lateral and longitudinal channels, then weighted fitting method is utilized to obtain the transfer functions of the two channel
摘要利用掃頻試飛技術獲取了某無人直升機在懸停工作點附近的舵機輸入和直升機動態輸出數據，利用組合窗頻譜分析的方法獲取了直升機橫滾通道與俯仰通道動態的頻率響應特性，利用加權擬合的方法獲取了各自的傳遞函數。 -
4. according to the analyses of underwater acoustic channel and long - range remote control receiving system, we designed the long - range remote control receiver, including a low noise prefix - amplifier, a band pass filter and an auto - gain control circuit. finally, the analog part of the receiver is tested and the frequency response of this receiving system is obtained.
結合對水聲通道特性和遠程遙控接收系統的分析，進行了遠程遙控接收機的設計，包括接收機低噪聲前置放大器的設計、帶通濾波器電路的設計和集成以及自動增益控制電路的設計，最後對接收機模擬電路進行了調試。 -
I designed both hardware and software to develop the multi - channel analyzer, of which the key is the pc / 104 embedded computer. in a word, it has five traits as follows : ( 1 ) the key of apparatus is the pc / 104 embedded computer ; ( 2 ) on the hardware, we introduce the high - speed a / d conversion component - max191 to improve the mca ' s conversion speed and meet the demand on the spot ; ( 3 ) adopting high frequency module of electrical source to reduce its volume. ( 4 ) the mca consumes low power no more than 3. 9 watt
以國土資源部項目為依託，以pc 104嵌入式微機為平臺，完成了小型、低功耗能譜採集系統，特點是： （ 1 ）以pc 104嵌入式微機為平臺，實現了採集系統微機化； （ 2 ）採用高速低功耗a d器件maxl91 ，與現有的mca相比，提高了轉換速度，降低了mca的功耗； （ 3 ）採用高頻模塊電源，減小了採集系統的體積； （ 4 ）整機功耗低，小於3 . 9w ； （ 5 ）儀器重量輕。 -
The simulation results based on siso and mimo systems show that the proposed scheme could effectively eliminate the time - variant fading characteristics of wireless channel and under an acceptable demand of ber, the frequency efficiency is enhanced greatly and besides, dynamic encoding is implemented with low complexity and high efficiency
通過在單天線和多天線系統中的模擬，表明該方案可以有效的克服無線通道的時變衰落特性，在滿足誤碼率性能要求的基礎上可以提高系統頻譜利用率，且實現復雜度低。 -
With the characteristics of large ambient noise, very narrow bandwidth, low carrier frequency, great propagation latency and time - space - frequency variant multipath effect ( mpe ), the stochastic ocean channel has demonstrated the greatest complexity and difficulty for underwater acoustic wireless communications. among them multipath effect ( mpe ) is the most difficult obstacle that results in signal fading and inter - symbol interference ( isi )
但是噪聲高、帶寬窄、載波頻率低、傳輸時延大、多途徑效應隨時間?空間?頻率變化等通道特性都會給有效、可靠的水聲通信帶來很大的麻煩，其中多途徑效應是最主要的困擾因素，它會導致信號幅度衰落和碼間干擾。 -
This master degree thesis, based on the observing of developing actuality of on - site electrical apparatus monitoring technology, aims at overcoming the problems existing in former on - site monitoring system, such as unable to realize multiple channels sampling and hold, unable to carry out multiple channel programmable magnification, unable to monitor frequency, low pick up bits, external rom low speed data saving, inefficient data query method, inflexible debugging and installation, low precision etc. by introducing eda ( electrical design automation ) technology, we put forward a creative circuit design scheme, which can considerable updated the on - site monitor system
本文根據電氣設備絕緣在線監測技術的發展現狀，針對以往在線監測數據採集系統存在的集成度低，不能實現多通路并行采樣，不能實現多通道同時程式控制放大，不能進行同步頻率監測，采樣位數較低，採用外部存儲器方式，對數據進行查詢的訪問方式，安裝調試不靈活等缺點，提出了應用現代微電子技術電子設計自動化（ eda ）技術實現對在線監測數據採集系統的改進。 -
The method was correlate search and fft carrier detection, which could solve the problem of the capture of the spread spectrum code under the condition of low snr and big frequency offset. we also put forward a method, shift receiving window and correlate with local sequence, which not only could solve the problem of symbol synchronization but also could acquire the statistics of the multipath. then we utilized the results of the channel estimation and the technology of rake receiver to decode the received spread spectrum sequence and acquire rude information
方案中提出了：相關搜索、 fft檢測信號載波的方法，解決了低信噪比、大頻差條件下擴頻碼的同步捕獲難題；滑動相關完成位同步的方法，解決了低信噪比下的同步問題；在時域利用相關進行通道估計，然後利用rake接收技術完成相關解擴的方法，一定程度上解決了多徑衰落影響解擴性能的問題。 -
This system realizes the underwater distance mobile security communication. the only shortage is the low velocity, which is result from the speciality of underwater channel and that spread spectrum need big frequency band
採用這一技術的水聲通信實驗系統成功的進行了湖上試驗，這種技術的不足是通信速率較低，這是由於水聲通道的特殊性以及擴頻技術要佔用大量帶寬所致。 -
A medium frequency - small size vector hydrophone of co - vibrating type is wrapped with low density compound material and in shuck only one piezoelectric ceramic accelerator is used for each channel to measure the vector components of the underwater acoustic field
摘要中頻小型同振式矢量水聽器採用低密度復合材料作為矢量通道外殼、壓電加速度計作為內部振動傳感器，以拾取水下聲場中的矢量信息。 -
The problem of signal processing for direct - sequence code - division - multiple - access ( ds - cdma ) signal over multipath frequency - selective mobile channels is considered. a new blind receiver is proposed. without the knowledge of the multiple - access interference users spreading code and the channel characteristics, the receiver achieves blind detection with prior knowledge of only the desired users spreading code and approximate timing. by using reduced rank adaptive decorrelating filter and adaptive multipath combiner which is based on decision - directed algorithm, the receiver gets the ability to combat both fading and the near - far effect at low cost. simulation results demonstrate that the proposed receiver offers high performance
本文研究多徑頻率選擇性衰落通道下直接序列擴頻碼分多址（ ds - cdma ）信號的處理問題，提出了一種新型的盲接收機.該接收機不需預知多址干擾用戶的擴頻碼，不需預知通道參數，只需已知期望用戶的擴頻碼和粗略的定時，就可以完成用戶的盲檢測.同時，該接收機通過降維自適應去相關濾波和基於判決指導的自適應多徑合併，來獲得低成本和良好的抗衰落、抗遠近效應性能.模擬結果驗證了本文提出的接收機的優良性能 -
Down link channel of new generation space tt & c system generally select qpsk as its modulation mode. firstly, carrier synchronization of qpsk is studied in the thesis, and then the key question - carrier synchronization in low snr and severe doppler frequency shift is systemic analyzed. in addition, different existing project are analyzed and compared
新一代航天測控系統的下行通道一般選擇qpsk作為其信號調制方式，本文首先研究了qpsk的載波同步問題，對其中的關鍵問題? ?低信噪比及大多普勒頻移情況下的載波同步進行了系統的分析，對現有的不同方案進行了分析與比較。 -
That is by inserting known symbols or pilots in time and frequency domain to estimate the channel frequency response. the proposed method employs iterative low - pass filtering in transform domain which can reduce additive white gaussian noise and inter - carrier interference effectively
該估計演算法採用在變換域多次迭代濾波的方式，能夠顯著降低高斯噪聲和載波間干擾（ ici ）對估計性能的影響，同時快速fft演算法也使得變換域濾波變得比較簡便。 -
In addition, the high and low frequency information of the adjacent channel can be transformed to the other seismic channel by taking the advantage of better similarity of subsection time - frequency analysis of seismic data, as well as the capability of learning, training and memorizing of the wavelet network
同時，利用地震資料分段時頻分析的相似性較好和小波網路學習、訓練及記憶能力較強的特點，可以較好地把井旁道的高、低頻信息轉換到相鄰道上。
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