The χ^2 family of signal fluctuation distributions represents the main fluctuation models which most radar targets follow it in their reflections. This family can be categorized as fluctuation distribution with two d...The χ^2 family of signal fluctuation distributions represents the main fluctuation models which most radar targets follow it in their reflections. This family can be categorized as fluctuation distribution with two degrees of freedom and those with four degrees of freedom. The first category represents all important class of fluctuation models which when illuminated by a coherent pulse train, return a train of fully correlated pulses （Swerling Ⅰ model） or fully decorrelated pulses （Swerling Ⅱ model）. The detection of this type of fluctuating targets is therefore of great importance. This paper is devoted to the analysis of Cell-Averaging （CA） based detectors for the case where the radar receiver noncoherently integrates M square-law detected pulses and the signal fluctuation obeys 2 statistics with two degrees of freedom. These detectors include the Mean-Of （MO）, the Greatest-Of （GO） and the Smallest-Of（SO） schemes. In these processors, the estimation of the noise power levels from the leading and the trailing reference windows is based on the CA technique. Exact formulas for the detection probabilities are derived, in the absence as well as in the presence of spurious targets. The primary and the secondary interfering targets are assumed to be fluctuating in accordance with the χ^2 fluctuation model with two degrees of freedom （SWI ＆ SWII）. The numerical results show that the MO version has the best homogeneous performance, the SO scheme has the best multiple-target performance, while the GO procedure does not offer any merits, neither in the absence nor in the presence of outlying targets.展开更多
The Godson-2G microprocessor is a high performance SOC which integrates a four-issue 64-bit high performance CPU core （called GS464）, a DDR2/3 controller, a HyperTransport controller, a PCI/PCI-X controller, etc. It...The Godson-2G microprocessor is a high performance SOC which integrates a four-issue 64-bit high performance CPU core （called GS464）, a DDR2/3 controller, a HyperTransport controller, a PCI/PCI-X controller, etc. It is physically implemented in 65 nm CMOS process and reaches the frequency of 1GHz with power consumption less than 4 W. The main challenges of Godson-2G physical implementation include nanometer process technology effects, high performance design targets, and tight schedule. This paper describes the key innovative features of physical design methodology which had been used in Godson-2G physical implementation, with particular emphasis on interconnect driven floorplan generation （ICD-FP）, adapted boundary constraints design optimization （ABC-OPT）, automatic register group clock tree generation methodology （ARG-CTS）.展开更多
VLIW(Very Long Instruction Word)指令因为含有较多的空操作导致严重的代码体积膨胀问题,代码压缩是解决这一问题的有效措施.VLIW代码压缩需要解决三个关键问题,一是提高压缩率;二是降低解压操作对性能的影响;三是分支目标重定位.针对...VLIW(Very Long Instruction Word)指令因为含有较多的空操作导致严重的代码体积膨胀问题,代码压缩是解决这一问题的有效措施.VLIW代码压缩需要解决三个关键问题,一是提高压缩率;二是降低解压操作对性能的影响;三是分支目标重定位.针对流体系结构上的VLIW指令特点,提出了二维压缩,对VLIW进行垂直与水平两个方向上的压缩,且水平解压可以与代码执行并行,并通过设置堆栈寄存器缓存循环入口地址.实验结果表明二维压缩有效解决了VLIW代码体积膨胀问题,可以使指令存储器的面积减少36.48%,并使得整个CISP系统面积减少了7.85%.展开更多
文摘The χ^2 family of signal fluctuation distributions represents the main fluctuation models which most radar targets follow it in their reflections. This family can be categorized as fluctuation distribution with two degrees of freedom and those with four degrees of freedom. The first category represents all important class of fluctuation models which when illuminated by a coherent pulse train, return a train of fully correlated pulses （Swerling Ⅰ model） or fully decorrelated pulses （Swerling Ⅱ model）. The detection of this type of fluctuating targets is therefore of great importance. This paper is devoted to the analysis of Cell-Averaging （CA） based detectors for the case where the radar receiver noncoherently integrates M square-law detected pulses and the signal fluctuation obeys 2 statistics with two degrees of freedom. These detectors include the Mean-Of （MO）, the Greatest-Of （GO） and the Smallest-Of（SO） schemes. In these processors, the estimation of the noise power levels from the leading and the trailing reference windows is based on the CA technique. Exact formulas for the detection probabilities are derived, in the absence as well as in the presence of spurious targets. The primary and the secondary interfering targets are assumed to be fluctuating in accordance with the χ^2 fluctuation model with two degrees of freedom （SWI ＆ SWII）. The numerical results show that the MO version has the best homogeneous performance, the SO scheme has the best multiple-target performance, while the GO procedure does not offer any merits, neither in the absence nor in the presence of outlying targets.
基金Supported by the National High Technology Research and Development 863 Program of China under Grant No.2007AA01Z114.
文摘The Godson-2G microprocessor is a high performance SOC which integrates a four-issue 64-bit high performance CPU core （called GS464）, a DDR2/3 controller, a HyperTransport controller, a PCI/PCI-X controller, etc. It is physically implemented in 65 nm CMOS process and reaches the frequency of 1GHz with power consumption less than 4 W. The main challenges of Godson-2G physical implementation include nanometer process technology effects, high performance design targets, and tight schedule. This paper describes the key innovative features of physical design methodology which had been used in Godson-2G physical implementation, with particular emphasis on interconnect driven floorplan generation （ICD-FP）, adapted boundary constraints design optimization （ABC-OPT）, automatic register group clock tree generation methodology （ARG-CTS）.
文摘VLIW(Very Long Instruction Word)指令因为含有较多的空操作导致严重的代码体积膨胀问题,代码压缩是解决这一问题的有效措施.VLIW代码压缩需要解决三个关键问题,一是提高压缩率;二是降低解压操作对性能的影响;三是分支目标重定位.针对流体系结构上的VLIW指令特点,提出了二维压缩,对VLIW进行垂直与水平两个方向上的压缩,且水平解压可以与代码执行并行,并通过设置堆栈寄存器缓存循环入口地址.实验结果表明二维压缩有效解决了VLIW代码体积膨胀问题,可以使指令存储器的面积减少36.48%,并使得整个CISP系统面积减少了7.85%.
