Crosstalk is the main degrading factor in Digital Subscriber Line (DSL) systems which are the result of electromagnetic coupling between two adjacent twisted pairs in a cable. Very-high bit-rate Digital Subscriber Lin...Crosstalk is the main degrading factor in Digital Subscriber Line (DSL) systems which are the result of electromagnetic coupling between two adjacent twisted pairs in a cable. Very-high bit-rate Digital Subscriber Line (VDSL) systems which use higher frequencies for data transmission than the other DSL systems, this effect is more considerable in Bit Error Rate (BER) degradation. This paper considers a complete adaptive iterative water-filling (IWF) algorithm for Resolving Upstream Near-Far Problem in VDSL Systems. The new distributed dynamic spectrum management algorithm is proposed, which improve achievable bit rate of iterative water-filling algorithm. The paper proffers a new power back-off strategy of the spectral mask at the near-end users, in order to protect the far-end users. Simulation of the proposed algorithm indicates that the bit rate is increased considerably rather the IWF and adaptive water-filling (AIWF) algorithms by keeping their low complexity. Furthermore, by adding the number of users in network, the new algorithm achieves performance gains over the AIWF, completely adaptive.展开更多
The electromagnetic radiation will result in informa- tion leakage being recovered when computers work. This article presents a high-speed real-time data acquisition system based on peripheral component interconnect ...The electromagnetic radiation will result in informa- tion leakage being recovered when computers work. This article presents a high-speed real-time data acquisition system based on peripheral component interconnect （PCI） bus and field programmable gate array （FPGA） for sampling electromagnetic radiation caused by video signal. The hardware design and controlling flow of each module are introduced in detail. The sampling rate can reach 64 Msps and system transfers speed can be up to 128 Mb/s by using time interleaving, which increases the overall sampling speed of a system by operating two data converters in parallel.展开更多
介绍一种新型的眼科超声生物显微镜系统．该系统利用长焦距(13mm)换能器和机械扇扫, 实现了宽景扫描,具有4．8 mm×6 mm 和9．6 mm×12 mm 两种扫描窗宽．使用长焦距换能器还使得检查时换能器远离角膜,极大地减小角膜损伤的风...介绍一种新型的眼科超声生物显微镜系统．该系统利用长焦距(13mm)换能器和机械扇扫, 实现了宽景扫描,具有4．8 mm×6 mm 和9．6 mm×12 mm 两种扫描窗宽．使用长焦距换能器还使得检查时换能器远离角膜,极大地减小角膜损伤的风险．用现场可编程门阵列器件(FPGA)实现了硬件动态帧平均从而增强了图像的信噪比．系统中心频率为50MHz,纵向和横向分辨力分别为50 μm 和100μm．一个专门设计的层状靶被用来测试系统的纵向分辨力,其独特的结构保证了高分辨力超声设备的测试精度．展开更多
文摘Crosstalk is the main degrading factor in Digital Subscriber Line (DSL) systems which are the result of electromagnetic coupling between two adjacent twisted pairs in a cable. Very-high bit-rate Digital Subscriber Line (VDSL) systems which use higher frequencies for data transmission than the other DSL systems, this effect is more considerable in Bit Error Rate (BER) degradation. This paper considers a complete adaptive iterative water-filling (IWF) algorithm for Resolving Upstream Near-Far Problem in VDSL Systems. The new distributed dynamic spectrum management algorithm is proposed, which improve achievable bit rate of iterative water-filling algorithm. The paper proffers a new power back-off strategy of the spectral mask at the near-end users, in order to protect the far-end users. Simulation of the proposed algorithm indicates that the bit rate is increased considerably rather the IWF and adaptive water-filling (AIWF) algorithms by keeping their low complexity. Furthermore, by adding the number of users in network, the new algorithm achieves performance gains over the AIWF, completely adaptive.
基金the National Natural Science Foundation of China （60331010, 60271018）.
文摘The electromagnetic radiation will result in informa- tion leakage being recovered when computers work. This article presents a high-speed real-time data acquisition system based on peripheral component interconnect （PCI） bus and field programmable gate array （FPGA） for sampling electromagnetic radiation caused by video signal. The hardware design and controlling flow of each module are introduced in detail. The sampling rate can reach 64 Msps and system transfers speed can be up to 128 Mb/s by using time interleaving, which increases the overall sampling speed of a system by operating two data converters in parallel.
文摘介绍一种新型的眼科超声生物显微镜系统．该系统利用长焦距(13mm)换能器和机械扇扫, 实现了宽景扫描,具有4．8 mm×6 mm 和9．6 mm×12 mm 两种扫描窗宽．使用长焦距换能器还使得检查时换能器远离角膜,极大地减小角膜损伤的风险．用现场可编程门阵列器件(FPGA)实现了硬件动态帧平均从而增强了图像的信噪比．系统中心频率为50MHz,纵向和横向分辨力分别为50 μm 和100μm．一个专门设计的层状靶被用来测试系统的纵向分辨力,其独特的结构保证了高分辨力超声设备的测试精度．
