精密基准源LM199的恒温电路机辅分析

基于精密基准电压源LM199的解剖,对其恒温电路作了全面的计算机辅助分析。对器件灵敏度、容差范围进行了分析,并进行了电路优化、器件模型参数优选,提出了关键设计参数、电路工艺难点及可实现性。     

A clock feedthrough reduction circuit for switched-current systems

A clock feedthrough reduction circuit useful for switched-current systems is proposed. This circuit adopts the concept of current cancellation. It is a signal-dependent clock feedthrough reduction circuit. To verify the usefulness of the proposed circuit, a test pattern was fabricated using 1.2 μm CMOS process. The simulation and the experimental results of the proposed circuit reveal a reduction of clock feedthrough errors in comparison with conventional circuits. The circuit based on this concept also permits a decrease in area of about 20%     

Monolithic arrays of surface emitting laser NOR logic devices

Monolithic, cascadable, laser-logic-device arrays have been realized and characterized. The monolithic surface-emitting laser logic (SELL) device consists of an AlGaAs superlattice lasing around 780 nm connected to a heterojunction phototransistor (HPT) in parallel and a resistor in series. Arrays up to 8×8 have been fabricated, and 2×2 arrays show uniform characteristics. The optical logic output is switched off with 40 μW incident optical input     

传输均匀场的加载介质壁矩形波导的研究

本文给出了一种能够传输均匀场的介质壁矩形波导，在数值计算的基础上得出了其结构参数；并进一步分析了加载工作物质对其场型的影响。     

Epitaxial lift-off GaAs HEMT's

An extensive study of epitaxial lift-off (ELO) Al_0.3Ga _0.7As/GaAs modulation doped heterostructure high electron mobility field-effect transistors (HEMT's) is presented. Effects of ELO on electron transport properties of two-dimensional electron gas at AlGaAs/GaAs interface are investigated. An ELO HEMT with 1.5 μm gate length had a maximum extrinsic transconductance g_m-max=125 mS/mm, a unity current gain cut-off frequency f_t=10.5 GHz, and a maximum frequency of oscillation f_max=12 GHz. Statistical distributions of maximum intrinsic transconductance of ELO HEMT's are presented and compared with their on-wafer counterparts. Stability of the ELO HEMT's has also been evaluated by continuous operation at room temperature under dc bias     

全离子注入C波段功率单片放大器及内匹配功率单片放大器

报道了全平面C波段功率单片放大器及四单片合成放大器研究结果。单片放大器采用全离子注入工艺，均匀性好，平均成品率40％，可靠性高。工作频率4．7—5．2GHZ，中心频率5．0GHz处输出功率2．5W，增益15dB，功率附加效率31．5％。单片放大器芯片面积2．8mm×2．0mm，四路合成的4×MMIC频率范围不变，中心频率4．95GHz处输出功率8．2W，增益13dB，功率附加效率26％，四路合成效率接近80％。实验结果与理论预测基本吻合。     

共享打印机接口设计

本文介绍了由单片机实现打印机共享接口电路的设计原理，该接口设计简单、可靠。     

Fixed Point Implementation of the QCELP Speech Coder

The Qualcomm code excited linear prediction (QCELP) speech coder was adopted to increase the capacity of the CDMA Mobile System (CMS). In this paper, we implemented the QCELP speech coding algorithm by using TMS320C50 fixed point DSP chip. Also the fixed point simulation was done with C language. The computation complexity of QCELP on TMS320C50 was about 33 MIPS and program size was 10k words and data memory was 4k words. In the normal call test on the CMS, where mobile to mobile call test was done in the bypass mode without double vocoding, mean opinion score for the speech quality was 3.11.     

SO42-/TiO2-Al2O3固体超强酸催化合成甲酸乙酯

用SO4^2-／TiO2-Al2O3固体超强酸作催化剂催化合成甲酸乙酯,考察了催化剂的活化温度、催化剂用量、反应物配比对酯化反应的影响。结果表明,SO4^2-／TiO2-Al2O3固体超强酸是合成甲酸乙酯的良好催化剂,并且可以重复使用。在醇酸摩尔比2：1、催化剂用量（以每摩尔甲酸计）2g、反应时间4h的最佳条件下,甲酸乙酯的产率可达99．5％。     

振动测量法评定磨损自修复添加剂的效果

针对现有测量自修复效果方法所存在的不足,提出了评定磨损表面自修复效果的振动测量新方法.研究表明,振动测量法评定磨损表面自修复添加剂的效果是可行的.