直接變換變頻 的英文怎麼說

中文拼音 [zhíjiēbiànhuànbiànbīn]
直接變換變頻 英文
direct converter
  • : Ⅰ形容詞1 (成直線的; 硬挺的) straight; stiff 2 (跟地面垂直的; 從上到下的; 從前到后的) erect; v...
  • : Ⅰ動詞1 (靠近;接觸) come into contact with; come close to 2 (連接; 使連接) connect; join; put ...
  • : 動詞1. (給人東西同時從他那裡取得別的東西) exchange; barter; trade 2. (變換; 更換) change 3. (兌換) exchange; cash
  • : Ⅰ形容詞(次數多) frequent Ⅱ副詞(屢次) frequently; repeatedly Ⅲ名詞1 [物理學] (物體每秒鐘振動...
  • 直接 : direct; immediate
  1. We developed the power system of electric drill based on dc - ac. the system use the technique of spwm frequency cowersation control. it changed th d. c provided by trolly wire of d. c motor into stable a. c adopted igbt and driving circuit adopted high speed module of exb840

    針對當前我國煤礦電鉆電源的使用現狀,提出研製dc - ac的電鉆電源系統,該電源系統利用spwm控制技術,將井下流電機車的架空線所提供的流電轉率是50hz的1 . 27v的穩定交流電。
  2. The architectures of the receiver are rf pass band direct sampling and if pass - band sampling with high - speed analog to digital converter after rf to if conversion. the first kind of architectures is hard to realize because of the requisition of devices is too high

    軟體無線電收機分為射帶通采樣和將射信號到中后再進行帶通采樣,前者實現較難,對器件的要求太高,然後進行各種數字處理。
  3. After establishing the model of intermediate frequency direct sequence spreading spectrum ( if dsss ) receiver, comparing and analyzing several conventional code acquisition methods, code and carrier two - dimension fast acquisition scheme based on two - dimension fft is proposed. finally, the situation for two targets is analyzed

    首先在建立了中收機的模型之後,本文對常用的偽碼捕獲方法進行了詳細地分析和比較,然後提出了本文的基於二維傅立葉技術的快速捕獲方法,並且分析了兩個目標時的情況。
  4. Due to the short distance among the planes which fly in a group, the conventional low resolution radar can not distinguish them in both distance and azimuth ? if we use the technology of isar to resolve the difference among doppler frequency of the targets and obtain a fine resolution cross - cross image, we may separate them, but a long time of coherent processing is needed <, for the formation targets, it can be approximately divided to rigid body and nonrigid body, so for the formation targets, that can be regarded as rigid which has a relative position and an identical movement, can be approximately considered as a large target, and be compensated by translational phase with the rule of minimum entropy, but for the most those cannot accord with the approximation of rigid, being the doppler - frequency of the aim is linear changed, by the relax method with short data, increases the resolving performance of multiple target to the aim in the frequency domain, since cross - range resolution is based on the accumulative time, so it is greatly improve the resolution to formation targets by the instant cross - range image which produced by radon - wigner transformation

    低分辨isan成像及干涉技術應用研究一因此無法分辨編隊目標的架數,我們借鑒isar的技術,通過較長時間的相干積累,在多普勒域上對目標進行分辨。而對于編隊目標,可分為近似剛性的多目標和非剛性的多目標,所以對于可以近似為剛體的編隊目標相對位置固定,運動方式一致,可以近似看作一個大目標,採用最小墑準則對平動相位的進行補償,但是大多數並不滿足剛體近似的編隊目標,由於目標在相干積累時間的多普勒率近似呈線性化,通過對較短數據利用relax的時分析方法,提高了率域上目標分辨的性能。由於橫向解析度取塊于橫向積累時間,所以利用radnwigner得到瞬時的一維橫向距離像大大提高了對編隊目標的分辨,對模擬和實測數據的大量分析結果表明此方法的有效性和可行。
  5. Because hrv signal is unevenly sampled, direct spectrum estimation will cause wrong result. resample on hrv signal is necessary. in this chapter after comparing different evenly sampling methods, the best way - cubic spline interpolation is adopted in spectrum estimation

    由於心率異信號是一種不等間隔采樣信號,不能採用傅立葉的方法進行譜分析,因此將心率異信號等間隔化是必要的。
  6. A novel communication receiver which uses lapped transform ( lt ) incorporating modified median filter ( mmf ) algorithm is designed for narrow - band interference excision. the lt domain mmf algorithm takes full advantages of the direct sequence spread spectrum signal, as well as the characteristics of lt, performing the transform domain filtering twice. the first filtering locates the position of interference and mitigates most of them. the second filtering is performed in a small neighborhood of the located interference. so lt domain mmf algorithm can completely mitigate the interference without distorting the desired signal. simulation results demonstrate the improved ber performance and increased robustness of our receiver

    本文採用改進的重疊域中值濾波演算法進行域抗干擾處理.該演算法既考慮到序列擴信號的特點,同時又利用重疊的特性對域系數進行了二次濾波.該演算法節省處理時間,並且不需要有關干擾的先驗知識,系統性能不會隨干擾化而化,因而是一種很穩健的處理方法
  7. The signal sampling circuit fulfill the tasks of sampling signal and changing the double polarities signal to the single polarity signal ; the drive circuit receives the pwm signals from dsp and pass the signals to ipm through optical - couple devices ; the protective circuit safeguard the system against high current, high voltage, low voltage and high temperature on the ipm model

    其中信號處理電路主要完成採集輸出電流和中間流環節電壓信號,並對採集到的電流信號進行極性處理的功能;驅動電路收dsp輸出的高驅動信號,通過耦合器件驅動ipm模塊;保護電路利用採集到電氣信號對整個系統實施保護,包括過電流、過電壓、欠電壓、 ipm模塊過熱等。
  8. Direct modulator converts baseband signal to rf signal without upconvertion. the system design is relatively simple compared to upconversion. so direct modulator provides adventages of compact size, low cost and low spurious response

    調制將基帶信號為射信號,不需要二次,與上方式相比系統結構簡單,降低了對濾波器的要求,具有體積小,重量輕,成本低等明顯的優點。
  9. Due to the component of natural gas is very complex in different zone of our country, the product has taked on special design, it set up moore component factor of thirteen kinds, which offer user to select and setup, so as to satisfy measurement for contains various component natural gas, at the same time established many take - pressure way in order to suit to different measure device, and have automatic calculate and display super - compression factor function

    A q型操作器輸出svout : 010ma 420ma 05v 15v信號,可驅動執行機構器或再由伺服放大器去驅動電動調節閥門或由電氣轉器和閥門定位器去驅動氣動薄膜閥。操作器處于自動工作狀態時,其信號輸入svin和操作輸出信號相當於是通的。以實現dcs系統或調節器對執行機構的自動控制。
  10. With the development of power electrical technology and power element product technics, vscf generating system has better foreground and more broad scope of development. and power inverter, which has important effect on the whole generating system, is the core of vscf generating system

    在交交型速恆電源系統中,功率器將流電轉為恆恆壓交流電為飛機用電設備供電,其工作狀況關繫到整個速恆電源的系統性能,因此是速恆電源系統的核心組成部分。
  11. A coherent electromagnetic pulse in the range between the far - infrared and microwave region is used as a detection source. the amplitude of the wave is recorded by electro - optical or photoconductive sampling. after fast fourier transform, the amplitude and phase of the wave is given, then the complex refractive index standing for the absorption and dispersion of the material in thz region is extracted

    Thz ( 10 ~ ( 12 ) hz )時域光譜技術是20世紀90年代發展起來的一種新型的光譜測量技術,它使用率介於遠紅外和微波之間的相干電磁輻射脈沖作為探測源,利用電光取樣或光電導取樣的方法記錄thz輻射電場的振幅時間波形,通過傅立葉得到測量信號振幅和相位的光譜分佈,進而獲得材料在thz波段的復介電常數,即色散及吸收等信息。
  12. There are different ways to make the bit synchronization, for example : the technique of the pilot frequency, the technique of some change about the baseband signal

    為了保證在同步傳輸系統中的位同步,有導及對基帶信號信號的方式,的方式中,使用線路編碼是比較常見的。
  13. According to the space vector modulation method of the equivalent structure of the ac - dc - ac transformation, the transformation relations of the matrix converter are deeply investigated. the ac - ac direct conversion control and the double - space - vector pwm scheme of the matrix converter are deduced, the four - step current commutation strategy of matrix converter is expatiated, the design method of input filter and over voltage protection circuit is analyzed, and the modeling and simulation of a three - phase matrix converter are implemented

    從等效交--交的空間矢量調制方法出發,深入分析了矩陣式器的關系,導出了交-交控制規律和雙空間矢量脈寬調制技術,闡述了矩陣式器的流控制策略,分析了輸入濾波器和過電壓保護電路的設計方法,實現了矩陣式器的建模和運行分析。
  14. Small size but high power, and it is very easy to install or ajust

    體積小功率大,安裝調試方便,兼容安川系列器,可以
  15. In chapter 3, the non - linear equation was linearized with the jacobi matrix, and then the linearized equation was transformed into fixed frame to analyze the stability problem with eigenvalue method ( on - ground or hovering ) or floquet theory ( forward flight ). meanwhile, the equation was perturbed by sweep frequency excitation from steady state to get transit decay of lag response which was then transformed into fixed frame with a numerical fourier coordination transformation ( fct ). the fixed frame response along with the body response was analyzed via an fft to determine modal frequencies

    然後,在穩態響應的基礎上利用雅各比矩陣對非線性方程進行了線化,線化后的方程利用多槳葉坐標到固定系下后,利用特徵值分析(地面、懸停)或floquet理論(前飛)對系統進行了穩定性分析;同時,對系統進行了瞬態響應分析;在系統達到穩態的基礎上進行掃激勵,用fft求得系統率,進而用移動矩形窗方法分析得到系統的阻尼。
  16. In fact, scaling technology is an essential component in many image / video processing such as to magnify / minify still image, to achieve special effect like picture - in - picture, to compress or transform digital video with spatial scalability etc. in this thesis we mainly employ this technology in video transcoding, which is a powerful but computationally intensive tools to convert one kind of video format into another, meeting different demand such as lower bitrates or various display terminals. in sum, there are two kinds of scaling schemes : one is in spatial domain and the other in transform domain. the scheme in transform domain can provide very good performance, that is, efficient computation and desirable image quality, whereas it has some disadvantage which is impossible or hardly to o vercome, especially some scenarios require arbitrary ratio zoom in horizontal and vertical, and excellent visual effect

    兩種方法都各有其利弊:域的方法是利用現有常用的視壓縮方案都是基於dct這個特點,所以可以域做處理,這樣可以節省大量的計算,但其缺點是由於dct是基於塊的,如8 8 ,所以很難找到一種方案可以進行任意比例的縮放,尤其是在縱橫縮放比例不一致的情形,但這對諸如hd縮放到sd和空域分級的壓縮方案來說尤為重要,基於空域濾波的方法卻沒有這樣的限制,同時可以保證縮放后的圖像的質量遠高於基於域的方法,為了達到高的縮放質量,就不可避免導致計算量過大。
  17. In addition, research on esprit ( estimation of signal parameter via rotational invariance technique ) super - resolution imaging technology is made to improve image quality, especially in the case of small segment of viewing angle. afterward, a new multi - target isar imaging method for high - speed targets is presented

    2 .在方位向的補償(相位校正)方面,利用多重的離散傅立葉( dcft ) ,對目標平動引起的相位線性調項的調斜率進行精確估計,並構造補償項對各個距離門進行補償。
  18. The thesis presents a group of direct ac / ac topologies including single and three phases ac / ac converters which are based on simple dc - dc topologies and realized by using the single - power tube four - quadrant switches. with only two power switches, these single or three phases ac / ac converters can achieve high quality four - quadrant ac / ac conversion by simple configurations and simple control schemes. the thesis mainly researches on the single phase ac / ac converter in the topologies including ac _ buck and ac _ cuk

    本文介紹了基於流buck 、 boost和cuk電路,採用單有源四象限開關實現功率雙向化的ac / ac拓撲族,該拓撲族中的單、三相電路均只使用兩個功率開關,可實現波形優良的同ac / ac四象限,具有電路結構簡單、控制簡便、可實現小型化等優點。
  19. The signals of multi - channel sensor at measuring spot were processed and translated by signal encoding technology to fuse into a baseband signal and then the signal was transmitted directly or in frequency - hand mode

    該方法利用信號編碼技術對測控現場的多路傳感器信號進行處理和,使其融合為一路基帶信號后,或以基帶傳輸或以帶傳輸。
  20. In the digital intermediate frequency project, the intermediate frequency signal is converted to digital signal directly into the dsp chip, then it is be processed by dft

    數字中方案將中信號通過a / d轉後送入dsp晶元進行dft,最後得到待測信號譜的采樣序列。
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