模转换

In order to tackle the power hungry problem of most existing analog-to-digital converter, the power optimization aim at data converters was put forward.

为了解决目前音频应用模数转换器功耗过大的问题，提出了模数转换器低功耗设计的目标。

The algorithm RSA is complicated and difficult in implementing, because it has to do modular exponentiation on largenumbers more than 512 bits.

分析了RSA算法的软件实现难点为大数的幂模运算，提出了将大数的幂模运算转换为小数幂模运算乘积的高效方法，并实现了RSA算法，该方法在理论分析和试验方面都具有较好的效果。

At first step, the processor before the deformable body contact the end face of cone die cavity regarded as an extrusion process. The minification of core boss's cross-section regarded as compressibility of direct extrusion, which acted as definition factor when construct the Direct Extrusion Model element. Another step, the model element of flat punch extrusion on wedge piece process was constructed when propose the process of deformable body overflow die corner. In this way the spherical end face of blank looked as cone end face one, t he approximate treatment is one of originality innovation in this paper. At last, the two elements have been connected and constructed the model element of cone boss part's deformation in the open die forging.

对于锥形凸台成形的第一个特征时段，即坯料和锥形凸台型腔的端面接触之前的变形过程，本文将凸台的截面缩小率转换成挤压成形的压缩率并以此为界定，建立了不同截面缩小率时的锥形模正挤压的模型单元；对于锥形凸台成形的第二特征时段即锥形模的角部充满过程，在详细考察锥形型腔端面对变形过程影响的基础上，将变形体的球形端面近似成锥面建立了平冲头挤压楔形体的模型单元；最后将前述两种模型单元有机连结，构建了开式模锻中整个锥形凸台成形过程的定量描述。

To the moduli with special forms (such as Mersenne numbers, pseudo-Mersenne numbers, generalized Mersenne numbers), we analysis and study modular arithmetic laws, and obtain the conclusions as follows: for Mersenne numbers and pseudo-Mersenne numbers, we get modular arithmetic formulas, and determine exact expressions of the number of modular addition to generalized Mersenne numbers generated by irreducible monic trinomials and pentanomials.

针对具有特殊形式的模数(如Mersenne数，伪Mersenne数，广义Mersenne数等)，深入分析了其取模运算规律，得到如下结果：对Mersenne数和伪Mersenne数，给出了取模运算转换为模加或模减运算的公式；对模数为任意首一三项式和五项式产生的广义Mersenne数，推导了相应取模运算的复杂度计算解析表达式。

In this study, we used the couple-mode theory for the simulation. We select the profile index of multimode fiber, profile index of mode conditioning patch cord and VCSEL output power as parameters for the simulation. The influence of using mode conditioning patch cord to the modal noise and modal coupling efficiency is showed.

利用模态耦合理论(Couple-Mode Theory)搭配多模光纤之折射率分布指数、多模模态调整转换跳接线之折射率分布指数及面射型雷射之模态分布，作为模拟计算依据，并利用OptSim模拟软体来模拟850nm面射型雷射与50μm多模光纤之光输出耦合情形。

In this topic, the dynamic analysis methods for piezoelectric vibrator are studied systematically based on the theoretical model, FEM numerical experimentation and FEM governing equation for given compound-mode vibrator, and some valuable conclusions are obtained. The main work accomplished is summarized as follows: 1.Elaborate the main modeling methods for piezoelectric vibrator and the significance and necessity to study the dynamic characteristics of piezoelectric vibrator which emphasize the urgency of this paper. 2.Take the bending deformation induced by piezoelectric ceramic as example, the energy transfer mechanism of electric energy to mechanical energy are analyzed; the motion and force transfer mechanism are analyzed for the longitudinal-bending vibrator. 3.Based on mode assumption and Hamilton principle, the coupling model of piezoelectric vibrator of linear USM is built; moreover, the equivalent circuit model is obtained and a coupling equation represents the relation between electric parameters and mechanical parameters is derived which provides foundation to match the vibrator and driving circuit. 4.Combine the constitutive equation of piezoelectric ceramic with elastic-dynamical equation, geometric equation in force field and the Maxwell equation in electric field and the corresponding boundary condition equation, the FEM control equation for piezoelectric vibrator of USM to solve dynamic electro-mechanical coupling field is established by employing the principle of virtual displacement. The equation lays the foundation to study the non-linear constitutive equation of piezoelectric ceramic driven by high-power. 5.Define the dynamic indexes of characteristic of vibrator and carry out variable parameters simulation by calculating the model parameters and the electric characteristics of vibrator are simulated according to the equivalent circuit model. By numerical experimentation, the working mode of vibration of vibrator and the shock excitation results of the working frequency band which provides the mode frequency to realize bimodal are analyzed. Detailed calculation of the electro-mechanical coupling field parameters is made by programming the FEM control equation.

本课题从理论模型、有限元数值试验、有限元控制模型等方面以复合振动模式振子为例对超声电机压电振子的动力学特性及其分析方法进行了全面系统地研究，得出了许多有价值的结论，主要概括如下： 1、阐述了目前针对超声电机压电振子的主要建模方法，对压电振子动态特性的研究意义和必要性进行了论述，突出了本文研究内容的迫切性； 2、以压电陶瓷诱发弹性体发生弯曲变形为例，分析了压电陶瓷通过诱发应变来实现机电能量转换的机理；对基于纵弯模式的压电振子的运动及动力传递机理进行了分析； 3、基于模态假定，利用分析动力学的Hamilton原理，建立了面向直线超声电机压电振子的机电耦合动力学模型，并据此建立了压电振子的等效电路模型，导出了电参量与动力学特性参量的耦合方程，为压电振子与驱动电路的匹配提供了依据； 4、从压电陶瓷的本构方程出发，综合力场的弹性动力学方程、几何方程、电场的麦克斯韦方程以及相应的边界条件方程，采用虚位移原理，建立了压电振子动态问题机电耦合场求解的有限元控制方程，为研究其大功率驱动下的非线性本构模型奠定了基础； 5、界定压电振子的动力学特性指标，对压电振子的机电耦合动力学模型参数进行计算及变参数仿真；依据等效电路模型，对压电振子的电学特性进行了仿真分析；通过有限元数值实验，对压电振子工作模态附近的模态振型及工作频率附近的频段进行了激振效果分析，找出了实现模态简并的激振频率；利用有限元控制方程，通过编程计算，对压电振子的力电耦合场参数进行了详细计算，得出了一些有价值的结论。

To change the representation of data from one form to another without changing the information they convey, e.g., radix conversion;code conversion; conversion from punched cards to magnetic tape; analog to digital conversion.

把数据从一种表示形式转换为另一种表示形式而不改变它所表达的信息。例如，基数转换、代码转换、穿孔卡片到磁带的转换、模-数转换。同transform。

The ADC is pipelined, including a single-input/difference-output sample/hold circuit and nine stage subcircuits. The preceding eight stages are 1.5bits/stage, and the last stage consists of two comparators. Every input sample is converted into 18 bits binary signals, and these binary signals are converted into 10 bits binary signals through digital correction circuit.

模数转换电路采用流水线式的结构，包括具有单端输入/差动输出功能的采样保持电路和九级的子电路，前八级子电路使用1.5位/级的结构，最后一级使用两个比较器实现，每个输入值被转换为18位的二进制代码，通过数字纠正技术最终实现10位的输出，按照前端电路的应用要求，这个模数转换器实现1.33MHz的采样速率。

Using staircase concatenation method SCM,the optimum coupling conditions were achieved for wedge-shaped fiber wedge angle,cylindrical endface lens curvature radius,semimajor axis of planar lightwave circuit elliptical field,aspect ratio of planar lightwave circuit elliptical field,misalignment tole.

在多量子阱-平面光波光路前置模斑转换器和不加模斑转换器的情况下，用阶梯串联法数值模拟并优化设计了楔形光纤-平面光波光路间最佳耦合参量：楔形光纤楔角45°、端面圆柱透镜曲率半径2。

Analogtodigital converter is very important in digital signal process board,so calculation of the effective numbers of bits is of great importance for evaluation of system performance.

将模拟信号转换为数字信号后再进行处理，是当前信号处理普遍使用的方法，模数转换器就是将模拟信号转换为数字信号的器件，所以计算其有效转换位数对系统性能评估就显得尤为重要。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。