An Improved Chua's Circuit and Its Use in Hyperchaotic Circuit

An improved implementation of Chua's circuit using dual output current conveyor is presented. The present proposal offers the advantages of low component count, current mode processing, availability of current across inductor and availability of voltage across inductor in form of current. The application of present circuit in designing low hardware inductorless hyperchaotic circuit is also presented. The paper concludes with a discussion of advantages of present proposal of Chua's circuit and inductorless hyper chaotic circuit thus designed over their earlier counterparts. The designs are adequately supported by SPICE simulation results. Patent pending.     

Modeling Energy Recovery Using Thermoelectric Conversion Integrated with an Organic Rankine Bottoming Cycle

Engine and industrial waste heat are sources of high-grade thermal energy that can potentially be utilized. This paper describes a model system that employs thermoelectric conversion as a topping cycle integrated with an organic Rankine bottoming cycle. The model has many parameters that define combined system quantities such as overall output power and conversion efficiency. The model can identify the optimal performance points for both the thermoelectric and organic Rankine bottoming cycle. Key analysis results are presented showing the impact of critical design parameters on power output and system performance.     

基于Monte Carlo方法的任意概率密度随机数字信号发生器设计

在信号处理和计算机微观模拟的过程中,经常要构造具有特定概率密度的随机数发生器.采用常规方法实现难度较大且不具普遍性,本文根据Monte Carlo方法基本原理和随机信号的数字特征给出一种任意概率密度随机数发生器的设计方法及核心源代码.实验证明该方法简单高效、通用性好.     

基于双向PWM变换器的微燃机发电系统起动／发电控制研究

针对微型燃气轮机（微燃机）发电系统的特点,建立了以电压型双向脉宽调制（PwM）变换器为功率变换装置的起动／发电控制模型。微型燃气轮机发电系统起动时,采用矢量控制;发电运行时,采用电压外环电流内环的双环PWM整流控制。仿真实验结果表明：起动时,高速永磁同步电机（PMSG）采用矢量控制比速度开环控制性能更优,减少了起动时间,满足快速起动的要求;发电运行时,与二极管整流相比,PWM整流能使交流侧电流跟踪发电机的感应电动势,功率因数约为1,降低了发电机侧的电流谐波,即减少了谐波热。同时保证了发电机在一定宽速范围内,输出直流电压稳定,并且在起动一发电过渡转换过程中,直流母线电压降落后,快速恢复为稳定值,满足平滑转换的要求。     

皮肤阻抗检测系统隔离刺激器的设计与实现

隔离刺激器是皮肤阻抗检测系统中重要的组成部分,根据检测系统的具体要求,提出一种新型的刺激器设计方案。该方案采用LM317HV调整刺激器信号的电压输出幅度,最高可达80 V;通过HV632调整输出脉冲的宽度和周期,从而实现一个幅度、脉宽和周期均可调的高压脉冲发生器。该刺激器具有操作简便、性能稳定、精度高和脉冲波形好等优点,可广泛应用于需要高压可调脉冲的场合,亦可对其进行扩展,满足具体的工程需求。     

人体死后经过的时间阻抗自动测量仪

本设计采用恒流源电路、双频交流发生器、交流测量电路、双单片机内部通信以及与微型计算机实时串行通信构成智能型人体电阻抗测定系统,可用于对案发现场的人死后人体电阻随时间的变化和现场的环境温度自动测量,由单片机进行数据实时采集、A/D转换和数据存储,把存储的数据通过RS-232发送给计算机,并对阻抗、频率、测量时间、测量速度、测量温度分类处理和计算,自动拟合出测量曲线.通过分析,最终确定人死后经过的时间(PMI).     

Plasmatron with Microwave Excitation of Nonequilibrium Plasma

Testing results of a microwave plasma generator (plasmatron) intended for excitation of a strongly nonequilibrium plasma arepresented. Nonequilibrium properties of the plasma are described in detail.The plasma flame is formed at an open end of a coaxial line under atmospheric pressure. Argon is used as plasma forming gas, and a 10 GHz CW magnetron with 10 W output power is used for plasma excitation.The efficiency of absorption of microwave power in the plasma is higher than90% with specific absorbing capacity of 0,4.4 kW/cm³     

Oscillator-Based Reconfigurable Sinusoidal Signal Generator for ADC BIST

In order to perform an on-chip test for characterizing both static and transmission parameters of embedded analog-to-digital converters (ADCs), this paper presents an oscillator-based reconfigurable sinusoidal signal generator which can produce both high and low frequency sinusoidal signals by switching the oscillator into different modes. Analog and digital signals can additionally be produced concurrently in both modes to provide not only test stimuli, but also reference responses for the ADC built-in self-test. The generated oscillation signal amplitude and frequency can be easily and precisely controlled by simply setting the oscillator clock frequency and initial condition coefficients. Except for a 1-bit digital-to-analog converter and smoothing filter, this proposed generator is constructed entirely by digital circuits, and hence easily integrates this silicon function and verifies itself before testing the ADCs.

高压钠灯电子镇流器的设计

高压钠（HPS）灯是高强度放电灯的一种,因其具有高光效（80～140 lm/W）、省电、寿命长和透雾性强等优点,而被广泛应用。传统的电感式镇流器存在功率因数低和自身损耗大的缺点,而且对电网电压波动的适应能力不强,所以研制性价比较高的电子镇流器取代电感式镇流器是大势所趋。目前,高压钠灯电子镇流器大多都是高频电子镇流器,在高频状态下,高压钠灯容易熄弧,存在声共振问题。文章利用可变频脉冲信号产生器设计的高压钠灯电子镇流器较好地避免了声共振问题,加上异常工作状态保护电路,使电子镇流器的性能显著提高。     

多功能便携式信号发生器设计

在现代测控领域,波形信号发生器已经成为系统研发和调试必不可少的工具。而目前市场上的信号发生器价格昂贵,体积比较大,不能满足实际的需要。针对信号发生器小型化便携式需求,设计了基于MSP430单片机的多功能信号发生器。介绍了相关原理,详细说明了软硬件设计,并对所产生的信号进行了误差测试分析。分析结果表明符合设计指标,具有很强的实用性。