LVDS三线同步串口的传输速率

搭建了一个合理的试验平台,利用FPGA产生10bit数字自校图形,经过LVDS同步串口传输,在数据接收端处理串转并数据送入图像采集卡,通过实时观察接收图形是否正常来判断该传输速率下的可靠性。分别研究了基于FPGA片内低压差分模块和专业差分转换芯片的两种应用方案。通过大量试验得出结论:两种方案的最高传输速率,前者约能达到152Mbit/s,后者约为125.2Mbit/s。考虑到工程实际中可能面临的各种复杂应用环境,推荐适当降额应用。     

A flip-chip packaged 80-nm In0.7Ga0.3As MHEMT for millimeter-wave low-noise applications

In this paper, we present a flip-chip 80-nm In_0.7Ga_0.3As MHEMT device on an alumina (Al₂O₃) substrate with very little decay on device RF performance up to 60 GHz. After package, the device exhibited high I_DS = 435 mA/mm at V_DS = 1.5 V, high g_m = 930 mS/mm at V_DS = 1.3 V, the measured gain was 7.5 dB and the minimum noise figure (NF_min) was 2.5 dB at 60 GHz. As compared to the bare chip, the packaged device exhibited very small degradation in performance. The result shows that with proper design of the matching circuits and packaging materials, the flip-chip technology can be used for discrete low noise FET package up to millimeter-wave range.     

Effect of Ta addition on magnetic properties of (Fe45Pt55)1−x-Tax thin films

It was studied that FePt-Ta thin films prepared on MgO (1 0 0) buffer-layer by DC/RF magnetron co-sputtering have shown better magnetic properties and micro structural improvement. The Ta-doped FePt-Ta films indicate somewhat differences in micro structural ordering and the aspect of grain growth after annealing. With respect to magnetic property, the sample having 30% increased coercivity was obtained after a heat treatment at 700 °C. In particular the addition of Ta (5.5%) enhances the L1₀ ordering of FePt at relatively high temperature (above 500 °C).     

基于MC/SG的双机热备系统设计与实现

详细介绍服务器双机技术,分析双机热备技术的主要功能,并根据企业系统的需求,提出双机设计方案,并对系统中双机热备实现细节进行相应的阐述。     

一种43 GHz超高带宽线性驱动电路设计

基于0.13μm SiGe BiCMOS工艺,设计了一种线性驱动电路。该电路具有高速和大摆幅的优势,能线性驱动行波马赫-曾德尔调制器(TW-MZM),可满足光通信系统100 Gbit/s单通道的应用需求。驱动电路包括连续时间线性均衡(CTLE)电路、可变增益放大(VGA)电路和基于Cascode结构改进优化的输出级电路,实现了增益可调,且避免发生由较大输出摆幅导致的晶体管击穿。仿真结果表明,电路的-3 dB带宽为43 GHz,其增益在15～25 dB内可调。在56 Gbaud NRZ/PAM4的输入信号下,测得的眼图形状良好,差分输出摆幅峰-峰值达4 V,电路整体功耗为1.02 W,面积为0.33 mm²。     

Rapid Chromatographic Analysis of Nucleosides and N-Bases in Physiologic Fluids

Abstract

A high-resolution anion-exchange system has been developed to analyze specifically for the nucleosides and bases present in physiologic fluids. This sytem employs a unique coupled-column operation that allows rapid column stripping and regeneration on completion of each run. Results obtained in the analysis of urine for nucleosides and bases are presented.     

Determination of Lead in Human Hair by High Resolution Continuum Source Graphite Furnace Atomic Absorption Spectrometry with Microwave Digestion and Solid Sampling

The content of lead in human hair was measured by high resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GFAAS) combined with microwave-assisted digestion (MAD) and direct solid sampling (DSS). Hair strands were washed, dried, and then cut into three parts (root, middle portion, and tip). For MAD-GFAAS assays, approximately 0.25 g of hair was completely digested using a mixture of concentrated nitric acid and hydrogen peroxide in a closed system. In the DSS-GFAAS assays, 0.1–0.2 mg of dried hair was directly introduced into a graphite furnace using a solid autosampler. The temperature programs were optimized and the effects of various added modifiers were compared. The results indicated that NH₄H₂PO₄ was the optimal modifier for analysis of Pb using GFAAS. Use of the optimal modifier and temperature program gave similar limits of detection for MAD-GFAAS and DSS-GFAAS of 1.16 ng/g and 0.82 ng/g, respectively. Both methods also produced satisfactory recoveries ranging from 98.69% to 103.14%. There was no significant difference observed between the Pb contents of hair strands determined by the MAD-GFAAS and DSS-GFAAS assays, which both indicated that the Pb levels increased along the hair strands. Comparison of the two methods revealed that DSS-GFAAS had several advantageous characteristics over MAD-GFAAS, including the need for much less sample material and having a less time-consuming procedure, lower sample blank absorbance, lower memory effect, and no risk of environmental pollution by digesting chemicals. The direct solid sampling technique can be employed as a good alternative to conventional wet digestion in AAS assays.     

高隔离度双极化微带天线直线阵的设计

本文介绍一种新型的1×16双极化微带天线直线阵的设计.该天线采用双极化角馈方形贴片单元,阵列的垂直极化端口采用共面馈电,水平极化端口采用口径耦合,并在馈电网络中应用反相馈电技术.实验结果表明,天线二端口驻波比小于1.5的相对带宽分别达到15％和13.5％,两端口之间的隔离度在频带内高于33dB,最大达到43dB.本直线阵可用作星载综合口径雷达系统的天线子阵,便于与有源收发器件结合.     

Precise Design of Millimeter Wave Quasi-Optical Faraday Rotators

A method of designing high performance millimeter wave quasi-optical Faraday rotators (QOFR) is reported in this paper. First, the dielectric and magnetic parameters for the ferrite sample are determined by fitting theoretical curves to the measured data. These fitted parameters are then used in a precise numerical model to predict the rotation angle and insertion loss of the QOFR. Finally, the parameters of the QOFR are optimized according to the requirements of devices. Examples are given showing the performance of the QOFR with an isolation better than 20 dB and an insertion loss less than 0.6 dB from 75 GHz to 95 GHz.     

一种改进的扬声器异常音快速检测方法

扬声器生产过程中,所有厂商都希望在装配流水线上快速生产出高质量的扬声器产品。扬声器的“异常音(Rub Buzz)”检测显得格外重要,目前生产厂家仍然以主观听音为主——依赖扫频仪,通过人工纯音检听进行判断,导致“异常音(Rub Buzz)”的判断标准因人而异的局面未能改善。虽然国内外也生产出一些异常音检测设备,但是检测速度慢、误判率高、价格昂贵等致命缺陷,至今扬声器生产厂家仍然将这一具有先进性的客观判断测量设备拒之门外。