A detailed design methodology of a micro-scale 2-DOF energy harvesting device that can harvest human motion energy of low frequency and wide bandwidth is developed. Based on the concept of the 2-DOF vibration absorber...A detailed design methodology of a micro-scale 2-DOF energy harvesting device that can harvest human motion energy of low frequency and wide bandwidth is developed. Based on the concept of the 2-DOF vibration absorber, device parameters are selected to harvest energy at low frequency of 1-10 Hz and wide bandwidth with ±20% of the mean frequency, which matches the human motion. The device dimensions are limited to 40 × 30 × 10 mm3 to fit with the human wrist size. Then, a finite element model is developed to investigate the system performance with the selected parameters. When subjected to harmonic excitation of 1 g, the proposed 2-DOF device is able to provide a power of at least 10 μW in between the two close resonant peaks of 4 Hz and 6 Hz, which is the target frequency range. The device shows very high power per square frequency compared with the reported harvesters.展开更多
Interconnect power and repeater area are important in the interconnect optimization of nanometer scale integrated circuits. Based on the RLC interconnect delay model, by wire sizing, wire spacing arid adopting low-swi...Interconnect power and repeater area are important in the interconnect optimization of nanometer scale integrated circuits. Based on the RLC interconnect delay model, by wire sizing, wire spacing arid adopting low-swing interconnect technology, this paper proposed a power-area optimization model considering delay and bandwidth constraints simultaneously. The optimized model is verified based on 65-am and 90-nm complementary metal-oxide semiconductor （CMOS） interconnect parameters. The verified results show that averages of 36% of interconnect power and 26% of repeater area can be saved under 65-nm CMOS process. The proposed model is especially suitable for the computer-aided design of nanometer scale systems-on-chip.展开更多
In software defined radio (SDR), sharp filters of different bandwidth are required to fine tune the desired channel. This requires different computational resources and large number of filter coefficients. This paper ...In software defined radio (SDR), sharp filters of different bandwidth are required to fine tune the desired channel. This requires different computational resources and large number of filter coefficients. This paper proposes a continuously variable bandwidth sharp finite impulse response (FIR) filter with low distortion and low complexity. For this, a fixed length FIR filter is used with two arbitrary sampling rate converters. This system can be used for both the continuous increase as well as decrease of the effective bandwidth of a filter. The low complexity and sharpness are achieved by using the frequency-response masking (FRM) approach for the design of the fixed length FIR filter. The sharp transition width leads to maximum rejection to channel interference in SDR.展开更多
Using a pump with a multi-line spectrum to broaden the Brillouin gain bandwidth is an effective way to achieve lowdistortion amplification with high gain. Here, we theoretically and experimentally investigate the gene...Using a pump with a multi-line spectrum to broaden the Brillouin gain bandwidth is an effective way to achieve lowdistortion amplification with high gain. Here, we theoretically and experimentally investigate the generation of a broadband Brillouin gain spectrum based on multi-frequency intensity modulation in an optical fiber. The arbitrary bandwidth of the Brillouin gain spectrum of stimulated Brillouin scattering(SBS) can be obtained as expected. In our experiment, a broadband Brillouin gain spectrum with a bandwidth of about 200 MHz is demonstrated. We also achieve a low-distortion amplification of a weak signal, whose maximum magnification is 65 d B for a-68-dBm input power signal.展开更多
为实现高能电子束发生轫致辐射产生的空间低强度脉冲X/γ射线的单粒子测量,本文基于近饱和放大时间过阈(time over threshold,TOT)技术,采用低带宽的运放和差分输出的甄别器,研制了一种用于硅光电倍增管(silicon photo-multiplier,SiPM...为实现高能电子束发生轫致辐射产生的空间低强度脉冲X/γ射线的单粒子测量,本文基于近饱和放大时间过阈(time over threshold,TOT)技术,采用低带宽的运放和差分输出的甄别器,研制了一种用于硅光电倍增管(silicon photo-multiplier,SiPM)的阵列型探测器全部通道读出的前端电子学系统。该系统能够获得能量、时间、强度等较为全面的物理信息,并在后端数字电路的FPGA内部通过脉宽和时间戳符合挑选出有效脉冲X/γ射线事件。本文详细介绍了前端电子学系统的设计方案、性能测试及功能验证等,并通过实验获得了低能区(50~200 keV)能量范围内的脉宽-能量谱和强度谱。测量结果表明:在低能区范围内,探测器阵列输出信号通过本文研制的前端电路处理后,脉宽和能量具有正相关关系,验证了脉冲X/γ射线有效事件识别的可行性;近饱和放大提高了定时精度,修正后可达800 ps。展开更多
以视频传感器和图像传感器为代表的有向传感器,在保持连通性的前提下,网络覆盖面积很难最大化,低速率拒绝服务攻击在小面积内会造成带宽混乱拥堵,造成网络带宽分配不佳、分配错误率较高。为此,提出一种低速率拒绝服务攻击下有向传感器...以视频传感器和图像传感器为代表的有向传感器,在保持连通性的前提下,网络覆盖面积很难最大化,低速率拒绝服务攻击在小面积内会造成带宽混乱拥堵,造成网络带宽分配不佳、分配错误率较高。为此,提出一种低速率拒绝服务攻击下有向传感器网络带宽分配方法。建立低速率拒绝服务攻击(Denial of Service attack,DoS)有向传感器网络模型。将攻击频率及攻击时间作为约束条件,采用设计的资源调度器控制有向传感器网络参数,使其满足资源动态调度性能需求。利用动态带宽分配算法设定三种采样周期,并通过调整采样周期实现带宽分配。仿真结果表明,所提方法的平均时延低于23 ms,带宽利用率为94%,节点平均队列长度低于1.9。验证了该方法具有可靠性更高的带宽分配结果。展开更多
文摘A detailed design methodology of a micro-scale 2-DOF energy harvesting device that can harvest human motion energy of low frequency and wide bandwidth is developed. Based on the concept of the 2-DOF vibration absorber, device parameters are selected to harvest energy at low frequency of 1-10 Hz and wide bandwidth with ±20% of the mean frequency, which matches the human motion. The device dimensions are limited to 40 × 30 × 10 mm3 to fit with the human wrist size. Then, a finite element model is developed to investigate the system performance with the selected parameters. When subjected to harmonic excitation of 1 g, the proposed 2-DOF device is able to provide a power of at least 10 μW in between the two close resonant peaks of 4 Hz and 6 Hz, which is the target frequency range. The device shows very high power per square frequency compared with the reported harvesters.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60725415 and 60971066)the National High-Tech Program of China (Grant Nos. 2009AA01Z258 and 2009AA01Z260)the National Science & Technology Important Project of China (Grant No. 2009ZX01034-002-001-005)
文摘Interconnect power and repeater area are important in the interconnect optimization of nanometer scale integrated circuits. Based on the RLC interconnect delay model, by wire sizing, wire spacing arid adopting low-swing interconnect technology, this paper proposed a power-area optimization model considering delay and bandwidth constraints simultaneously. The optimized model is verified based on 65-am and 90-nm complementary metal-oxide semiconductor （CMOS） interconnect parameters. The verified results show that averages of 36% of interconnect power and 26% of repeater area can be saved under 65-nm CMOS process. The proposed model is especially suitable for the computer-aided design of nanometer scale systems-on-chip.
文摘In software defined radio (SDR), sharp filters of different bandwidth are required to fine tune the desired channel. This requires different computational resources and large number of filter coefficients. This paper proposes a continuously variable bandwidth sharp finite impulse response (FIR) filter with low distortion and low complexity. For this, a fixed length FIR filter is used with two arbitrary sampling rate converters. This system can be used for both the continuous increase as well as decrease of the effective bandwidth of a filter. The low complexity and sharpness are achieved by using the frequency-response masking (FRM) approach for the design of the fixed length FIR filter. The sharp transition width leads to maximum rejection to channel interference in SDR.
基金Project supported by the National Natural Science Foundation of China(Grant No.61605034)
文摘Using a pump with a multi-line spectrum to broaden the Brillouin gain bandwidth is an effective way to achieve lowdistortion amplification with high gain. Here, we theoretically and experimentally investigate the generation of a broadband Brillouin gain spectrum based on multi-frequency intensity modulation in an optical fiber. The arbitrary bandwidth of the Brillouin gain spectrum of stimulated Brillouin scattering(SBS) can be obtained as expected. In our experiment, a broadband Brillouin gain spectrum with a bandwidth of about 200 MHz is demonstrated. We also achieve a low-distortion amplification of a weak signal, whose maximum magnification is 65 d B for a-68-dBm input power signal.
文摘以视频传感器和图像传感器为代表的有向传感器,在保持连通性的前提下,网络覆盖面积很难最大化,低速率拒绝服务攻击在小面积内会造成带宽混乱拥堵,造成网络带宽分配不佳、分配错误率较高。为此,提出一种低速率拒绝服务攻击下有向传感器网络带宽分配方法。建立低速率拒绝服务攻击(Denial of Service attack,DoS)有向传感器网络模型。将攻击频率及攻击时间作为约束条件,采用设计的资源调度器控制有向传感器网络参数,使其满足资源动态调度性能需求。利用动态带宽分配算法设定三种采样周期,并通过调整采样周期实现带宽分配。仿真结果表明,所提方法的平均时延低于23 ms,带宽利用率为94%,节点平均队列长度低于1.9。验证了该方法具有可靠性更高的带宽分配结果。
