Threshold of environmental elements in drainage basin sediment yield refers to, under effect of climate, underlying surface and human activity, a turning point of abrupt changes in drainage sediment yield related to e...Threshold of environmental elements in drainage basin sediment yield refers to, under effect of climate, underlying surface and human activity, a turning point of abrupt changes in drainage sediment yield related to environmental element characteristics. Previous studies on threshold of sediment yield of relevant drainage basins were mainly concentrated on impact of natural zones with a few researches on impact of other environmental elements. Particularly studies on compound environmental element threshold in drainage basin sediment yield remain blank today. Studies indicate that sediment yield in drainage basins is affected by compound interactions and complex actions. Based on single element analysis, the present paper gives quantitatively compound threshold of environmental elements affecting sediment yield of the drainage basin between Hekouzhen and Tongguan in the middle Yellow River by the method of multi-variant, polynomial formula regression analysis.展开更多
连续时间Sigma-Delta调制器被大量应用于音频电子系统及其他领域。设计采用单环二阶连续时间系统架构,包含分段式7 bit Flash量化器,提出了双噪声耦合结构。通过对系统结构的改进,二阶系统有很好的稳定性,能实现三阶的噪声整形效果,对DA...连续时间Sigma-Delta调制器被大量应用于音频电子系统及其他领域。设计采用单环二阶连续时间系统架构,包含分段式7 bit Flash量化器,提出了双噪声耦合结构。通过对系统结构的改进,二阶系统有很好的稳定性,能实现三阶的噪声整形效果,对DAC失配、环路延时、放大器有限带宽等非理想特性有着非常好的鲁棒性。仿真结果显示,在3 M的输入信号带宽,16倍的过采样率时,调制器信噪失真比(SNDR)达到96.9 d B,有效比特数(ENOB)为15.8 bit,输入信号动态范围(DR)为98 d B。展开更多
基金supported by the State Key Basic Research Development Project(Grant No.1999043604)the National Natuural Science F oundation of China(Grant No.40471085)+1 种基金the Joint Proj ect of the National Natural Science Foundation of Chinathe Yellow River Water Conservancy Committee(50239080).
文摘Threshold of environmental elements in drainage basin sediment yield refers to, under effect of climate, underlying surface and human activity, a turning point of abrupt changes in drainage sediment yield related to environmental element characteristics. Previous studies on threshold of sediment yield of relevant drainage basins were mainly concentrated on impact of natural zones with a few researches on impact of other environmental elements. Particularly studies on compound environmental element threshold in drainage basin sediment yield remain blank today. Studies indicate that sediment yield in drainage basins is affected by compound interactions and complex actions. Based on single element analysis, the present paper gives quantitatively compound threshold of environmental elements affecting sediment yield of the drainage basin between Hekouzhen and Tongguan in the middle Yellow River by the method of multi-variant, polynomial formula regression analysis.
文摘连续时间Sigma-Delta调制器被大量应用于音频电子系统及其他领域。设计采用单环二阶连续时间系统架构,包含分段式7 bit Flash量化器,提出了双噪声耦合结构。通过对系统结构的改进,二阶系统有很好的稳定性,能实现三阶的噪声整形效果,对DAC失配、环路延时、放大器有限带宽等非理想特性有着非常好的鲁棒性。仿真结果显示,在3 M的输入信号带宽,16倍的过采样率时,调制器信噪失真比(SNDR)达到96.9 d B,有效比特数(ENOB)为15.8 bit,输入信号动态范围(DR)为98 d B。
