direct modulation 中文意思是什麼

direct modulation 解釋
直接調節
  • direct : adj 1 筆直的,一直線的;正面的。2 直接的。3 直截了當的,直率的,明白的。4 直系的,正統的。5 【語...
  • modulation : n 調整,調節;(聲調的)抑揚,變化;【音樂】轉調,變調;【無線電】調制。 amplitude modulation 振...
  1. As an example, the detection problem of noise frequency modulation jamming signal was analyzed, two accumulation detection methods, direct accumulation detection and binary accumulation deteceion, were proposed, and the detection probability of the two methods was calculated

    摘要以噪聲調頻干擾為例,對干擾信號的檢測問題進行了分析,提出直接積累檢測和二進制積累的檢測方法,並計算了兩種方法的檢測概率。
  2. The modulation circuit utilized the vector modulation technology based on fourth - harmonic mixer. the lo frequency is only quarter of carrier frequency. direct high speed qpsk digital modulation of millimeter wave signal can be realized with fairly simplified lo circuit

    調制電路採用了以四次諧波混頻器技術為核心的矢量調制技術,利用1 / 4載波頻率作為本振信號,實現了對毫米波信號直接進行高速qpsk數字調制。
  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. The paper adopted advanced rf direct digital modulation scheme

    本文採用先進的射頻直接數字調制/解調技術方案。
  5. In this paper, microwave t / r front - end for short distance wireless communication is realized in miniature based on low cost mcm - l technology. the main jobs are as follows : 1. the performances of i / q modulation and direct converter receiver are analyzed to set down the system scheme

    主要工作包括以下幾個方面: 1 .基於目前流行的數字中頻接收技術,分析了i / q調制和直接變頻接收機的性能,提出超外差變頻的總體系統方案。
  6. Secondly the detection precision is only related to the synchronization phase but not to the amplitude of the mainline voltage because that it uses the optimized pulses synchronous with the mainline voltage as modulation signals. thirdly it decreases the requirement of the input low pass filter and eliminates the error resulting from the direct component and even harmonics of load current. the most significant merit is that it can eliminate the effect of a few low order odd harmonics and the detecting circuit is easy to be implemented

    模擬和實驗結果表明該方法的主要優點有:不需使用乘法器進行信號調制,調制信號採用與電網電壓同步的優化特定脈沖,其檢測精度只與同步相位有關,而與電網電壓幅值無關;降低了對輸入低通濾波器的通頻帶要求,直流和偶次諧波分量對檢測精度沒有影響;突出的優點是可以消除有限個低奇次諧波對檢測結果的影響。
  7. The forming of signals, such as those employed in telegraph transmission, by the interruption of a direct current or modulation of a carrier between discrete values of some characteristics

    斷開或接通直流電路或者在具有某些特點的離散值之間對載波進行調制而形成信號的過程和方法。如電報傳輸中使用的就是鍵控法。
  8. In this paper, direct modulation technology working at microwave band is researched

    本文研究的是微波波段的直接調制技術。
  9. In high - speed direct optical modulation of laser diodes, the frequency chirp of the modulated signal cannot be eliminated. then the optical external modulators play more and more important role in large capacity optical transmission systems, and have become a subject of intense study

    在高速光調制中,直接調制引起的啁啾噪聲難以克服,光外調制器在大容量光纖傳輸系統中,扮演著越來越重要的角色,成為當前的研究熱點。
  10. Aiming to achieve mini - type designment, and transmitting farther on the setting frequency band, direct frequency modulation is chosen after comparing the advantage of amplitude modulation with that of frequency modulation

    為了實現微小型化的設計,並且使系統在設定的傳輸頻段上傳輸距離較遠,在比較調幅與調頻的優缺點后,我們選擇了直接調頻的調制方式。
  11. The principle advantages of vcsels over conventional edge - emitting lasers lie in ultralow threshold current, small far - field divergent angle, high modulation frequency, potential for wafer level testing and the ease for single longitudinal mode operation and two - dimension integration. as a result they show considerable promise for applications such as optical fiber communication, parallel optical interconnects, optical information processing and neural networks, etc. a direct coupling theoretical model in quasi - three - dimension for the gain - wave guide vertical - cavity surface - emitting lasers has been created in this paper

    它與傳統的邊發射激光器相比具有更優越的特性,例如,具有極低的閾值、較小的遠場發散角、調制頻率高、易實現單縱模工作和二維集成,無須解理封裝即可進行在片測試等,所以,它被廣泛應用於光纖通訊、并行光互聯、光信息處理、光神經網路等領域。
  12. The thesis used a fully digital method that employed the principle of direct digital frequency synthesis to realize the modulation based on dsp

    本文採用了完全數字化的方法,是利用直接數字頻率合成技術的原理,並基於dsp的系統實現msk調制。
  13. 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。
  14. 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-直-交變換的空間矢量調制方法出發,深入分析了矩陣式變頻器的變換關系,導出了交-交直接變換控制規律和雙空間矢量脈寬調制技術,闡述了矩陣式變頻器的換流控制策略,分析了輸入濾波器和過電壓保護電路的設計方法,實現了矩陣式變頻器的建模和運行分析。
  15. Besides these, it is capable of performing frequency conversion with sinusoidal output voltages and currents at the desired output frequency and allows bi - directional power flow according to the space vector modulation method of the equivalent structure of the ac - dc - ac conversion, the conversion relations of the matrix converter were deeply investigated. the ac - ac direct transformation control and the double - space - vector pwm scheme of the matrix converter were deduced and the modeling, sin ~ iu1ation and experiment of a three - phase matrix converter were implemented

    本文從等效交一直一交變換的空間矢量調制方法出發,深入分析了矩陣式變換器的變換關系,推導出了交一交直接變換控制規律和雙空間矢量pwm調制技術,實現了交一交直接變換控制方式下矩陣式變換器的建模和運行分析,並進行了計算機模擬和實驗研究。
  16. Study of intensity modulation - direct detection laser system for detection of sound vibration

    強度調制直接探測型遠距離激光聲探測系統研究
  17. In order to solve the problem of direct torque control ( dtc ) for permanent magnet synchronous motor ( pmsm ) related to the flux and the torque ripple and the uncertainty of switching frequency, a method which shorten the voltage - vector - function - time by svm ( space vector modulation ) is developed, and in order to improve the system performance, the stator flux linkage sectors and vectors are subdivided

    摘要為了解決永磁同步電機傳統直接轉矩控制低速時磁鏈和轉矩脈動大的問題,提出了1種用空間矢量調制( svm )實現減小電壓矢量在1個控制周期中的作用時間的直接轉矩控制方法;為進一步提高系統性能,對磁鏈扇區和電壓矢量進行了細分。
  18. Despite their invasive nature, direct methods should be favoured to adequately measure airway remodelling in disease and its modulation by therapy

    雖然這些是有創的檢查,但是使用直接的檢測技術以更充分的測定在疾病中氣道重構的發生和治療后氣道重構的改善還是更受推崇的。
  19. Direct torque control using space vector modulation ( svm - dtc ) scheme is discussed and the detailed designed, including space vector choosing and modulating, to overcome the control difficulties coming with the characteristic of low inductance. comparing with the basic dtc, the simulation results confirm the feasibility and good performance of this strategy. in order to reduce the torque error in dynamic state resulted from the nonlinear relationship between the torque and torque angle, a proportional - plus - integral ( pi ) torque controller with variable proportion is presented to ensure exact and quick control of torque in dynamic state

    系統的闡述了永磁同步電機直接轉矩控制理論,分析了改進后的svm - dtc控制策略,並具體設計了控制技術的實現方案,包括參考矢量的生成和空間電壓矢量調制的方法;為減小電磁轉矩與轉矩角非線性關系這一因數給電機電磁轉矩動態調節造成的誤差,本文實現了變比例系數轉矩pi調節器的方案,確保了系統穩定性的同時,實現了電磁轉矩在動態過程中快速而準確調節。
  20. The direct torque control theory is a kind of new control method after vector control theory in ac control field. it calculates and controls the torque and the flux of ac electromotor in stator coordinate using the voltage space vector. adopting the stator magnetism field direction method, it recurs to discrete pang - pang control producing pulse width modulation signal and controls the switch state of the transductor when better quality steady - state performance is produced

    直接轉矩控制技術是繼矢量控制技術之後交流調速領域中新興的控制技術,它採用空間矢量分析的方法,直接在定子坐標系下計算並控制交流電動機的轉矩和磁鏈,採用定子磁場定向,藉助于離散的兩點式控制產生脈寬信號,直接對逆變器的開關狀態進行最佳控制,以獲得轉矩的高動態性能。
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