低載頻調制 的英文怎麼說

中文拼音 [dīzǎibīndiàozhì]
低載頻調制 英文
low carrier modulation
  • 載 : 載Ⅰ名詞（年） year : 一年半載 six to twelve months; six months to a year; 三年五載 three to five ...
  • 頻 : 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...
  • 調 : Ⅰ動詞1 （配合得均勻合適） harmonize; suit well; fit in perfectly 2 （使配合得均勻合適） mix; adju...
  • 制 : Ⅰ動詞1 （製造） make; manufacture 2 （擬訂; 規定） draw up; establish 3 （用強力約束; 限定; 管束...
  1. However, the efficiency of pwm at light load is low and the filter design of pfm is rather difficult due to the random characteristic of the frequency spectrum distribution

    採用相應調制方式的ic品種繁多，各有千秋。但pwm在輕載時效率較低，而pfm由於頻譜分佈隨機，不利於后續濾波器的設計。
  2. 1 m 0. 5, the phase - shifted angle 6 is controlled in term of sine law which makes the magnitude of resonant voltage track a reference sine voltage, and the resonant voltage is rectified, filtered, inverted and then the better sine - voltage output is obtained, theoretical analysis and experimental results show that for the resistive load and inductive load, the switches of leading leg of the phase - shift - controlled circuit are always turned on at zvs, and ones of lagging leg are turned on at zvs ( < 0 ) or turned off at zcs ( ( > 0 ), moreover, all switches in the low - frequency inverter are always turned on and off at zvs, the measured circuit efficiency for rated load reaches up to 88 %

    從功率單向流動角度出發，提出了一種lcc諧振型恆頻移相單相高頻鏈逆變電路拓撲，在調制系數0 . 1 m 0 . 5情況下，控制移相角按正弦規律變化，使諧振電壓脈沖列的幅值追蹤參考正弦電壓信號，經過整流、濾波、低頻逆變，從而獲得正弦度較好的輸出電壓。理論分析和實驗結果證明對于阻性負載或阻感性負載，移相全橋具有超前橋臂零電壓開通，滯后橋臂或者零電壓開通（ _ 0 ）或者零電流關斷（ _ 0 ）的軟開關特性，而低頻逆變器的各個開關均實現零電壓條件下的開通與關斷。
  3. This paper mainly focuses on the noise limiting by means of the direct sequence spread spectrum ( dsss ) and the analysis of the transmission performance of the plc and some digital modulation technology. the contents of the paper is as follows : 1 ) the technical feasibility is proved after simulating noise limiting principle of dsss by means of systemview, the simulation software ; 2 ) a kind of band pass filter ( bpf ) is realized according to the requirement of filter and the principle of butterworth approximation, which satisfies the index of performance of dsss. 3 ) the low voltage plc system includes the sc1128, the specific modulation / demodulation ic, the bpf filter and other circuit components, furthermore, the control function of system is realized by means of the personal computer and the microcontroller

    本課題在對低壓電力線的傳輸特性和數字調制技術進行分析的基礎上，將通信理論中的直接序列擴頻技術（ dsss ）用於解決低壓電力線通信的干擾問題，主要研究內容如下： （ 1 ）用通信模擬軟體systemview對dsss技術的通信和抗干擾原理進行模擬分析，分別對時域和頻域下採用dsss技術前後接收信號的頻譜進行分析，驗證dsss技術在本系統中的可行性； （ 2 ）由dsss技術對濾波系統的要求，根據濾波理論分析了巴特沃思型濾波器的逼近原理並設計了合適的濾波電路； （ 3 ）用調制解調晶元sc1128和自行設計的濾波器加之輔助外圍電路，構造出低壓電力線載波通信系統，並採用atmel公司的單片機設計了接收和發射電路的微控制器； （ 4 ）分別對採取抗干擾措施前後輸入和輸出信號進行對比實驗，並對結果進行分析，驗證了dsss技術對干擾信號的抑制作用。
  4. This product, adopted pwm integrated circuit and mosfet, igbt that were imported from the overseas, has the following merits : quick - response, strong interfere - proof, stable frequency and voltage, low consumption when light loading, high efficiency and reliable performance, it can be applicable to the family use, pasture region, work with the wind generator and some other places where the power failure often occurs

    本品採用pwm （脈寬調制）集成電路和進口大功率mosfet 、 igbt等器件，具有應變快、抗干擾、自動穩定頻率和電壓、空載損耗低、效率高、性能可靠，是家庭，牧區，風力發電機配套以及其它野外經常停電地區提供交流電的必備的電器。
  5. There are five parts are as follows : in part one, the concept of switching function is introduced first to establish the nonlinear mathematical model of the induction motor variable frequency speed adjustment system which is fed by a sine pulse width modulated ( spwm ) inverter and takes the effect of the main magnetic circuit saturation into consideration, then the low frequency oscillation of the system is simulated according to the model. next, from the view point of energy conversion of the inverter - induction system, a criterion for the low frequency oscillation is proposed to determine whether the system is in low frequency oscillation which is judged by whether the interval of the negative current component of the inverter input current is more than 1 / fc ( fc is the carrier wave frequency of the inverter ) or not

    首先引入開關函數概念，建立了正弦脈寬調制（ spwm ）逆變器供電異步電動機，考慮主磁路飽和時的變頻調速系統整體數學模型，模擬系統的低頻振蕩；其次從逆變器-異步電動機系統能量轉換角度出發，提出通過檢測逆變器輸入電流中負電流的間隔時間是否大於1 / f _ c （ f _ c為逆變器載波頻率）來判定系統是否出現低頻振蕩；最後的實驗結果驗證了系統低頻振蕩建模和判據的實用性和正確性。
  6. This paper presented a general systematic view, application and current development of the power line carrier transmission technology, and clearly compared some existing power line carrier communication chip with each other. then the authors analyze the channel " s characters of low voltage power line, and formed an abstract carrier channel model. using this as its basis, a new kind of transmission technology is designed that adopted transmission technology combining the spread spectrum modulation with channel coding, which can solve the problems above mentioned to a certain degree, and need not pay for high cost

    文章不僅全面地介紹了電力線載波通訊技術的特點、應用及其發展狀況，還對目前的電力線載波通訊晶元進行了比較；並通過對低壓電網通道特性的分析和研究，抽象出其載波通道模型，在此基礎上，提出了將擴頻調制和通道編碼相結合的傳輸技術用於低壓電力線載波通信，這可以在很大程度上解決電力線的干擾問題，且不必付出高昂的代價。
  7. Green - mode which provides off - time modulation to linearly decrease the working frequency under light - load conditions and power limiting which will turn off the transistor when peak current of inductor reaches the threshold current

    同時該電路集成了能在輕負載情況下自動降低頻率的綠色模式以及能在電感峰值電流過高時關斷調整管的功率限制模塊，降低了系統的功耗。
  8. The tap - changer is made with solid state relay as its working mechanism and controlled by microprocessor. this switch has totally cancelled the mechanical drive organization, by the microprocessor according to the voltage of second side microprocessor decide the working condition of solid state rely, high regulation speed, need not transition resistor, rush current is low. operating frequently ; there is no electric arc to produce, can put in the fuel tank of the voltage transformer directly ; the structure is simple, the fabrication cost is low, benefit and use widely among the voltages transformer of distribution

    其中的有載調壓分接開關，它是一種完全由固態繼電器作為分接開關執行機構，由單片機控制的有載自動調壓的變壓器分接開關。該開關完全取消了機械傳動機構，由單片機根據變壓器二次側電壓的高低，決定與變壓器各分接頭聯接的固態繼電器的工作狀態。調節速度快，改變分接頭時不需過渡電阻，沖擊電流小，可頻繁操作；無電弧產生，可以直接放在變壓器油箱中；結構簡單，造價低，便於在配電變壓器中推廣使用。
  9. The " remote sense " returns a low side of load voltage that is impressed on the audio to suppress crosstalk and to provide optimal analog audio and analog video

    "遙感"會讓加載在音頻上的電壓負荷回到較低的一端，從而抑制交調失真，達到理想的模擬音頻和模擬視頻效果
  10. We analyzed the anti - jam and band inside anti - interfere performance of the system, and the low probability intercept ( lpi ) of the traditional direct sequence spread spectrum ( dsss ) modulations in the uav platform ' s applications. so a new modulation technique using a multi - level pseudo noise ( pn ) code has been presented. the new multi - level pn code is built from a high speed pn code through a low passed filter ( lpf )

    分析了系統抗阻塞式干擾和抗帶內頻帶干擾的性能，以及常規bpsk qpsk - dsss調制在無人機通信中存在的安全隱患，提出了一種用多電平pn碼進行擴頻調制的方法：採用高速pn碼，經過低通濾波器，產生多電平pn碼進行直序擴頻調制，能在低信噪比情況下有效抵抗平方率檢測器對系統載波的檢測。
  11. Because frequency - shift signal is a kind of modulation signal, it ' s waveform is two ac sine signal of alternating i. e. upper frequency and lower frequency which was generated by low frequency modulating middle frequency

    由於移頻信號是一種調頻信號，其波形為低頻信號調制中心載頻信號后產生的低端載頻（下邊頻）和高端載頻（上邊頻）兩個交替變化的正弦交流信號。
  12. The main results and creative points in the dissertation were as follows : a ) by means of studying on the fiber - optic hydrophones ’ tdm array based on phase generated carrier ( pgc ) demodulation with laser frequency modulation, the mathematic models were set up, used for theoretical analyses of noncoherent crosstalks in the system using low coherent laser and coherent crosstalks in the system using high coherent laser. the formulas calculating crosstalks were given, and the method measuring crosstalks was shown definitely

    本論文的主要研究結果和創新在於: 1 、通過對基於光頻調制pgc （相位生成載波）解調光纖水聽器時分復用系統的研究，針對低相干光源的串擾強度迭加和高相干光源串擾的相干迭加，建立了理論分析的數學模型，得出了計算串擾的公式，明確了測試系統串擾的方法。
  13. 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。
  14. Spindle and circular knife force use cvt system and frequency conversion system, may do high and low adjusting speed and positive & negative switching control to achieve best cutting quality

    主軸與圓刀動力使用無級變速系統和變頻系統，可做高低調速及正反轉切換控制，達到最佳載切質量。
  15. The list betterments aimed at the properties of system : through the testing of dc voltage, pulse width and inverting voltage and frequency can be regulated online to fit for different steady load ; reducing speed ripples by compensating with nonzero voltage working proportional time ; adopting the technology of harmonics suppression. as a result, the high precision and wide speed control is realized and the step out is overcome

    針對系統的性能指標，做了如下改進：對直流側電壓的檢測，在線調整逆變器導通脈寬、輸出電壓和頻率，可以適應不同大小的恆負載；並用非零電壓矢量作用時間進行補償的方法，減小電機的低速脈動；加入了諧波抑制技術等。
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