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给出了一种以单片集成PLL片ADF4106为核心,并通过AT89C2051单片机对ADF4106进行控制来实现锁相频率合成器的设计方法。文中在介绍了ADF4106芯片的内部功能结构的基础上,探讨了锁相频率合成器的基本原理和工作特性;给出了基于ADF4106的锁相频率合成器的硬件电路结构和软件程序设计方法。该设计经仿真测试证明.锁相效果良好,结构精简,性能可靠。 相似文献
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本文从扩大人民币汇率浮动范围的角度出发,考察了汇率目标区理论以及Edwards的基本因素模型对确定目标区中心汇率的贡献,并结合我国1986-2003年间宏观经济基本因素和人民币实际汇率走势,用基本因素模型建立了与我国实情相应的均衡汇率模型。得出的结论是:影响人民币均衡汇率的主要基本因素有全要素生产率、对外偿债能力和政府支出,这与我国区域广阔、国内资本市场不发达以及政府在经济发展中占主导地位的特点是一致的;因此,在人民币汇率改革中可以考虑汇率目标区,并使用类似的基本因素模型来确定基准汇率和目标区边界;在目前条件下,±5%的变动幅度是可以接受的。 相似文献
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《Wave Motion》2020
Engineering structures for different dispersion and dissipation levels of wave propagation use internal variable models, which may enhance the performance of acoustic metamaterials (AMMs). In this study, the wave dispersion and dissipation performance of AMMs is studied using an anelastic displacement fields (ADF) model. A symmetric state-space method based on Floquet-Bloch’s theorem for a nonviscously damped unit cell is developed. The study also constructs Bloch’s eigenvalue problems built from the symmetric state-space formulation to obtain the wavevector-dependent damped frequency and damping ratio for wave propagation analysis of periodic structures. The effects of wave dispersion and dissipation on the performance of AMMs are studied by using two numerical examples of mass-in-mass lattice systems containing multiple resonators. It is shown that nonviscous damping increases the wave dispersion performance of AMM. It is also shown that the metadamping phenomenon enhances the wave dissipation performance of AMM. It is demonstrated that the new method in symmetric form is applicable for performance analysis of periodic phononic crystal. 相似文献
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Windows 图像采集(WIA)为Windows 系统提供数字图像获取服务,是图像获取设备获取图像的重要方法之一。WIA提供了MiniDriver和MicroDriver两种方式以支持扫描仪获取图像。本文首先介绍了WIA的一般概念和体系结构,然后在此基础上又分别详细介绍了MiniDriver和MicroDriver的实现,最后对实现过程中一些典型问题进行了分析。本文以微软MSDN文献为基础,结合实际的项目经验,提出了WIA Driver的实现思路及典型问题的解决方法,对相关的开发者具有重要的借鉴意义。 相似文献
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The PyFrag program (released as PyFrag2007.01) is a "wrap-around" for the Amsterdam Density Functional (ADF) package and facilitates the extension of the fragment analysis method implemented in ADF along an entire potential energy surface. The purpose is to make analyses of reaction paths and other (in principle also multidimensional) potential energy surfaces more transparent and user-friendly. PyFrag also automates the analysis of reaction paths in terms of the extended activation strain model of chemical reactivity. 相似文献
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结合锁相频率合成基本原理以及高集成锁相频率合成芯片ADF4360—1工作特性,设计一个稳定的2.33GHz本振源电路模块,应用于中频射频发信机中。详细介绍了核心芯片的结构、原理及应用,并给出完整的硬件电路。经仿真测试,该电路的性能指标基本符合要求。 相似文献