C1786显示器开关电源有两大特点:首先是有完善的节能控制系统,在节能的暂停和OFF状态符合EPA制定的节能管理标准.其次是开关电源驱动系统和开关电路采用仙童公司生产的新FPS单片开关电源器件(Fairchild power Switch的字头)因而该电源...C1786显示器开关电源有两大特点:首先是有完善的节能控制系统,在节能的暂停和OFF状态符合EPA制定的节能管理标准.其次是开关电源驱动系统和开关电路采用仙童公司生产的新FPS单片开关电源器件(Fairchild power Switch的字头)因而该电源有暂停,软关机(OFF)状态,工作状态之间转换时开关电源初级控制系统无需作任何控制,只要切断次级相关功能电路的供电开关电源可自动根据负载功率调整其工作状态.需注意的是FPS单片开关电源中KA5H/5M/5L系列和KASS系列是不同的.本文介绍的是Liteon C1786彩显中应用的最新FPS产品KA5SXX系列的功能和特点:展开更多
In this paper the authors explore the Global Positioning System （GPS） signal acquisition and tracking algorithms used in software GPS receiver. Acquisition time is the most important parameter in evaluating the perf...In this paper the authors explore the Global Positioning System （GPS） signal acquisition and tracking algorithms used in software GPS receiver. Acquisition time is the most important parameter in evaluating the performance of a software GPS receiver in terms of its speed. A trade-off study is done to seek a good balance between the acquisition accuracy and the processing time. The frequency-domain acquisition method by circular correlation, used in a software GPS receiver, has been improved by studying the power spectrum of the Coarse Acquisition （C/A） code alone. The analysis of C/A code reveals that its power spectrum is symmetrical; hence only half the points are required to perform circular correlation. Besides, either half of the spectrum is asymmetrical where a larger amount of power is concentrated in almost one-quarter of the spectrum on its either sides. This further reduces the number of points used to perform correlation. Comparative results of MATLAB simulation of full-size, half-size and quarter-size circular correlation done on actual data stored on hard disk are provided, and they agree with those obtained using GPS receiver. Further reduction in acquisition time has been achieved by investigating the effect of length of the noncoherent pre-integration period. The improved acquisition methods pave way for further development of new algorithms to enhance software GPS receiver performance.展开更多
文摘C1786显示器开关电源有两大特点:首先是有完善的节能控制系统,在节能的暂停和OFF状态符合EPA制定的节能管理标准.其次是开关电源驱动系统和开关电路采用仙童公司生产的新FPS单片开关电源器件(Fairchild power Switch的字头)因而该电源有暂停,软关机(OFF)状态,工作状态之间转换时开关电源初级控制系统无需作任何控制,只要切断次级相关功能电路的供电开关电源可自动根据负载功率调整其工作状态.需注意的是FPS单片开关电源中KA5H/5M/5L系列和KASS系列是不同的.本文介绍的是Liteon C1786彩显中应用的最新FPS产品KA5SXX系列的功能和特点:
文摘In this paper the authors explore the Global Positioning System （GPS） signal acquisition and tracking algorithms used in software GPS receiver. Acquisition time is the most important parameter in evaluating the performance of a software GPS receiver in terms of its speed. A trade-off study is done to seek a good balance between the acquisition accuracy and the processing time. The frequency-domain acquisition method by circular correlation, used in a software GPS receiver, has been improved by studying the power spectrum of the Coarse Acquisition （C/A） code alone. The analysis of C/A code reveals that its power spectrum is symmetrical; hence only half the points are required to perform circular correlation. Besides, either half of the spectrum is asymmetrical where a larger amount of power is concentrated in almost one-quarter of the spectrum on its either sides. This further reduces the number of points used to perform correlation. Comparative results of MATLAB simulation of full-size, half-size and quarter-size circular correlation done on actual data stored on hard disk are provided, and they agree with those obtained using GPS receiver. Further reduction in acquisition time has been achieved by investigating the effect of length of the noncoherent pre-integration period. The improved acquisition methods pave way for further development of new algorithms to enhance software GPS receiver performance.
