main carrier frequency 中文意思是什麼
main carrier frequency
解釋
主載波頻率-
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。 -
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。 -
In this paper, aimed at the problems existed in theoretical analysis and application of ftm, the discrete fourier transform method is applied to analyze the traditional ftm ( tftm ). and computer simulation is applied. the main propose is to solve the problem, such as frequency shifting, selection of carrier frequency big or small and selection of filter window size. considering the feature of double - exposure holographic interferometry, we propose a modified ftm ( mftm )
針對二次曝光數字全息干涉術中ftm存在的理論缺陷和具體應用到二次曝光全息干涉計量中存在的問題，本文從離散傅立葉變換的角度對傳統的傅立葉變換法（ tftm ）進行了理論分析和計算機模擬計算，並重點致力於解決ftm中的移頻問題、載頻大小的選擇以及濾波窗口大小的選擇等關鍵問題，結合二次曝光全息干涉的特點提出了改進的傅立葉變換法（ mftm ） 。
分享友人