摘要：A rally integrated receiver RF front-end that meets WCDMA/GSM system requirements is *** supports SAW-less operation for *** improve the linearity in terms of both IP3 and IP2,the RF front-end is comprised of multiple-gated LNAs with capacitive desensitization,current-mode passive mixers with the proposed IP2 calibration circuit and reconfigurable Tow-Thomas-like biquad TIAs.A new power-saving multi-mode divider with low phase noise is proposed to provide the 4-phase 25%-duty-cycle *** addition,a constant-g_m biasing with an on-chip resistor is adopted to make the conversion gain invulnerable to the process and temperature variations of the *** RF front-end is integrated in a receiver with an on-chip frequency synthesizer in 0.13μm *** measurement results show that owing to this high-linearity RF front-end,the receiver achieves -6 dBm IIP3 and better than ＋60 dBm IIP2 for all modes and bands.

摘要：A RF low noise amplifier,integrated in a single bluetooth transceiver chip and fabricated in 0.35μm digital CMOS technology,is *** the consideration of ESD protection and package,design methodology is discussed from the aspects of noise optimization,impedance match,and forward *** 2.05GHz,the measured S 11 is -6.4dB, S 21 is 11dB with 3dB-BW of 300MHz,and NF is about *** indicates that comprehensive consideration of parasitics,package model,and reasonable process is necessary for RF circuit design.

摘要：基于场致发射理论提出描述电火花加工(Electrical discharging machining,EDM)过程的平板电容模型,将单脉冲放电周期依次划分为极间电场建立、极间通道击穿、正常放电加工与消电离四个阶段,并分别进行各阶段的极间电场强度、极间电子自由程、极间介质介电常数和极间电流变化规律的理论分析。讨论EDM加工能量大小的影响因素,并给出基于该模型的极间电压与放电电流变化的仿真步骤与方法集。设计通孔加工试验和实时电流与电压采集电路,并基于该模型对极间电压与电流的变化曲线进行Simulink仿真程序设计。试验结果表明,相同加工参数实测曲线与仿真试验图形实现了较好的吻合,而且试验结果统计分析表明,该模型对不同电极材料与加工参数对加工效率的影响可做出合理解释且对加工效率有着良好的预测能力,证明了该模型的合理性与有效性。

摘要：机床特性主要依赖于零部件刚度及结合部刚度组成的系统刚度特性,滚珠导轨结合部刚度是系统刚度的主要组成部分。滚珠导轨副由若干个滑块和轨道组成的滚珠导轨单元结合部构成,一个滚珠导轨单元结合部包括多列、多个圆柱面-球面结合面。基于单位面积结合面基础特性参数,提出一种直线滚珠导轨圆柱面-球面结合面静特性解析方法,并通过实例计算与加载试验验证比较,证明本文方法的正确性,为圆柱面-球面结合面的设计分析提供支持。

摘要：A fully integrated low power transmitter for an IEEE 802. llb transceiver system is implemented in SMIC 0.18μm technology. The direct-conversion transmitter includes two Chebyshev I low pass filters,two PGAs,a SSB mixer, and a PA driver. The transmitter provides a gain control of 32dB in 3dB steps. The maximum output power is - 3.4dBm and the EVM is 6. 8%. The power consumption of the transmitter is only 57.6mW with a 1.8V power supply. The chip area of the transmitter is 1.6mm × 1.6mm.

摘要：A 2.4GHz monolithic CMOS receiver with direct-conversion architecture is presented. This quadrature receiver is designed for 802.11b wireless LAN applications at the maximum data rate of 11Mbps as a low-cost solution. Five key blocks,i, e., a low noise amplifier （LNA）, a down-conversion mixer, a variable gain amplifier, a low pass filter, and a DC- offset cancellation circuit,are designed based on system design and low noise high linearity considerations. The necessary auxiliary circuits are also included. Fabricated in SMIC 0.18μm 1p6m RF CMOS process, the receiver＇s performance is measured as：4. 1 dB noise figure, - 7.5dBm input third order intercept point （IIP3） for LNA ＆ mixer at high gain setting, - 14dBm IIP3 for the whole receiver,53dBc @30MHz offset of adjacent channel power rejection,and less than 5mV out- put DC-offset. The receiver consumes 44mA under a 1.8V power supply with I,Q two paths.

摘要：为了提高移动机器人在作业站点的定位精度,在考虑入射角的基础上,分析了发散角对超声波传感器测距的影响,建立了同时考虑发散角及入射角的超声波传感器测距函数关系表达式;提出了超声波传感器发散角的标定方法,并通过实验对发散角进行了标定;通过对比实验可以看出,所提出的关系表达式提高了超声波传感器距离测量精度。在此基础上提出了利用自动导航车(AGV)单个侧面两个超声波传感器实现移动机器人在作业站点侧向、前向及姿态3个方向的位姿定位方法,最后将该方法用于自主研发的移动机器人的定位试验,验证了该方法的正确性和有效性。

摘要：提出一种五面加工的六轴混联机床的设计方案。以典型刀具和工件加工时的相对运动要求为输入,得到刀具和工件的位姿关系矩阵,用机床的串并联运动功能模型实现了刀具和工件的位姿关系。六轴混联方案中,主轴部件一侧采用可实现Z轴移动和A及B摆动轴进给的少自由度3-PRS并联机构,工作台一侧采用X-Y并联驱动和C轴数控转台的串联机构。安装在3-PRS并联机构动平台上的主轴部件通过倾斜布局、合理构件(组件)设计使刀具的摆动范围达到了±45°;并对3-PRS并联机构进行了运动、刚度和工作空间分析。分析了X-Y并联平台与X轴滑台和Y轴滑台之间4条导轨副的受力状态。

摘要：研究了考虑结合部特性的机床结构动力学特性的系统建模解析方法。将整机结构用梁元件、弹簧元件和集中质量元件来等效,并将结合部特性引入到整机模型中,基于边界元法建立了整机结构的动力学方程,快速地求得了整机结构相应的动力学特性。数值算例与实验结果表明,上述方法不但节约了计算量,而且具有很高的精度,可有效地解决各种复杂系统结构的动力学建模解析问题。上述方法对于提高机床结构的理论计算和设计水平具有十分重要的意义。

摘要：为了实现对数控车削中心主轴箱刚度准确评价及给主轴箱结构改进方案提供负载下刚度检测依据,深入研究全载荷加载装置的加载原理,提出自动变位全载荷下车削中心主轴箱静刚度检测方法,研制全载荷加载装置,应用自动变位全载荷加载装置对车削中心施加载荷进行主轴箱静刚度检测试验;采用有限元法计算全载荷下车削中心主轴箱的静刚度及刚度分布,分析了主轴箱的刚度分布特点;在试验和有限元分析的基础上改进了主轴箱结构的设计方案,修改主轴箱与床身连接的螺栓结合部,使主轴箱静刚度得以提高;通过将改进前后的试验结果与有限元分析进行对比,验证了试验方法的正确性以及基于螺栓结合部的改进方案的有效性。