As the tuning frequency of an integrated LC-voltage controlled oscillator （LC-VCO） increases, it is difficult to co-design the active negative resistance core and the varactor to achieve wideband frequency range, lo...As the tuning frequency of an integrated LC-voltage controlled oscillator （LC-VCO） increases, it is difficult to co-design the active negative resistance core and the varactor to achieve wideband frequency range, low phase noise, constant bandwidth and small tuning gain together. The presented VCO solves the problem by designing a set of changeable varactor units. The whole VCO was implemented in a 0.18μm CMOS process. The measured result shows -120 dBc/Hz phase noise at 1 MHz offset. The measured tuning range is from 4.2 to 5 GHz and the tuning gain is 8-10 MHz/V. The VCO draws 4 mA from a 1.5 V supply voltage.展开更多
阐述基于180nm CMOS工艺的一种用于传感器AFE(Analog Front End, AFE)的低噪声恒定带宽PGA电路设计,其1~4级为可选接入级,采用基于全差分放大器的低噪声开环结构。最后一级为推挽输出的增益精调级,采用基于跨导-跨阻闭环反馈型结构。芯...阐述基于180nm CMOS工艺的一种用于传感器AFE(Analog Front End, AFE)的低噪声恒定带宽PGA电路设计,其1~4级为可选接入级,采用基于全差分放大器的低噪声开环结构。最后一级为推挽输出的增益精调级,采用基于跨导-跨阻闭环反馈型结构。芯片测试结果表明,该PGA的增益范围为0~66.7dB,步进为1dB;在1.8V供电电压下,功耗为1.01mW;等效输入噪声为3.9μ VRMS(1~100kHz积分)。此外,由于最后一级采用跨导-跨阻结构,该PGA的增益曲线还具有恒定带宽的显著优势。展开更多
为有效管理分布式开放实时系统(Distributed Open Real-Time System,DORTS)的CPU和网络资源,提供实时应用端到端延时确保,提出一种基于资源预留的分层调度策略。对于任务的调度,首先利用最大需求任务优先与最小可利用率节点适应算法将...为有效管理分布式开放实时系统(Distributed Open Real-Time System,DORTS)的CPU和网络资源,提供实时应用端到端延时确保,提出一种基于资源预留的分层调度策略。对于任务的调度,首先利用最大需求任务优先与最小可利用率节点适应算法将任务分配到各节点,然后在节点上采用基于服务器的两层调度架构进行调度;对于消息的调度,采用3层调度架构:在顶层为每个应用创建一个高级别调度器,负责调度应用产生的消息;在中间层为每个节点创建一个低级别调度器来调度所有的高级别调度器;在底层,一个介质访问控制调度器用于授权各节点对网络的访问。设计了EDF-SS(Earliest Deadline First with Slack Stealing)算法用于改进软实时非周期消息的响应性。仿真实验证明了算法的有效性。展开更多
文摘As the tuning frequency of an integrated LC-voltage controlled oscillator （LC-VCO） increases, it is difficult to co-design the active negative resistance core and the varactor to achieve wideband frequency range, low phase noise, constant bandwidth and small tuning gain together. The presented VCO solves the problem by designing a set of changeable varactor units. The whole VCO was implemented in a 0.18μm CMOS process. The measured result shows -120 dBc/Hz phase noise at 1 MHz offset. The measured tuning range is from 4.2 to 5 GHz and the tuning gain is 8-10 MHz/V. The VCO draws 4 mA from a 1.5 V supply voltage.
文摘为有效管理分布式开放实时系统(Distributed Open Real-Time System,DORTS)的CPU和网络资源,提供实时应用端到端延时确保,提出一种基于资源预留的分层调度策略。对于任务的调度,首先利用最大需求任务优先与最小可利用率节点适应算法将任务分配到各节点,然后在节点上采用基于服务器的两层调度架构进行调度;对于消息的调度,采用3层调度架构:在顶层为每个应用创建一个高级别调度器,负责调度应用产生的消息;在中间层为每个节点创建一个低级别调度器来调度所有的高级别调度器;在底层,一个介质访问控制调度器用于授权各节点对网络的访问。设计了EDF-SS(Earliest Deadline First with Slack Stealing)算法用于改进软实时非周期消息的响应性。仿真实验证明了算法的有效性。
