The Nanomechanical Bit

The applicability of nanomechanical devices for computational approaches is reviewed. The focus is on the representation and processing of information based on nanomechanical bits. Several device concepts are discussed ranging from nano‐electromechanical systems in silicon to circuits based on carbon nano‐tube switches, combinations of nanomechanical resonators and traditional transistors, and integration into a computing architecture. The strengths of mechanical systems include their scalability, robustness to external electrical shocks, and their low‐energy consumption. Hence, they may lead the way to new forms of ultradense memory and alternative routes of computing. In conjunction with quantum mechanical single electron circuits, nano‐electromechanical systems may also have potential for quantum computational circuits.     

一种CMOS张弛振荡器的设计与分析

针对在较宽的电源电压和温度变化范围内一般的振荡器频率误差较大的问题,研究并设计了一种广泛用于电荷泵(ChargePump)电路和DC/DC电压转换电路的高稳定性的CMOS型OTA-C张弛振荡器;该振荡器利用基准电流源产生的恒流源对电容进行充放电,同时利用高速度、低功耗的跨导运算放大器OTA作比较器比较阈值电压,再经整形滤波电路产生频率为1MHz方波信号;该电路采用0.6μm的CMOS工艺设计,利用Hspice进行仿真验证,结果表明,温度在-40℃~85℃,同时电源电压在2.6V~5.5V之间变化时,该张弛振荡器振荡频率随温度和电源电压的变化很小,总体误差在±2.5%以内,比较适合于产生低速时钟信号;此电路已成功集成到某型DC/DC电压转换芯片之中。     

可去抖动的时钟脉冲发生器

为了克服晶体振荡器的温漂问题,提高时钟精度,控制输出脉冲。本文设计了一种脉冲发生器,采用基于分频链的时钟校准方法,结合脉冲控制电路,可以输出标准时钟脉冲。标准时钟脉冲在脉冲发生器的控制下产生频率和脉冲个数都可调节的脉冲序列,其校准精度达±0.25 ppm,校准范围±32 ppm。经仿真验证,该方案符合设计初衷,达到设计要求。     

质量-弹簧振子系统的ANSYS有限元分析

对质量-弹簧振子系统进行的ANSYS有限元模态分析,得出了与理论计算特征频率完全一致的结果。通过这种相互一致的印证,可以确信关于弹簧有效质量的理论计算公式是准确、可靠的。     

微型自动喷灌控制系统的设计

为设计一种符合温室生产特点的微型自动喷灌控制系统,采用多谐振荡电路产生计时脉冲,14位计数器CD4060进行分频,共同组成一超长定时器,驱动控制电路和执行装置实现自动喷灌操作。实用证明,该电路可在喷灌时间5 s-1.5 min、间歇时间1 min-1.5 h之间任意调节,较好地解决了小水量持续供水模式的温室生产实践问题。该系统只需在原供水装置上增设自动控制电路即可实现,结构简单,工作可靠,具有一定的实用价值和推广前景。     

一种电容式触摸输入模块的设计

针对传统机械按键式输入方式易磨损、寿命短等不足,设计了一种电容式触摸输入模块。分析了电容式触摸的基本原理,包括接触前后电容值变化和对变化电容值的检测,并对现有的几种电容检测方法的优缺点和易于实现程度进行了详细阐述;设计了一种基于松弛振荡器电容值检测方法的电容式触摸输入模块的方案,并给出了基于PSoC微处理器的电容式触摸模块的软硬件设计流程。实验表明设计的电容式触摸输入模块精确度较高,灵敏度可调,误操作率低,具有一定的工程应用价值。     

在恒定弱电场中一维线性谐振子能级的计算

线性谐振子在量子力学中占有重要的地位,许多体系都可以近似地看做是线性谐振子.因此,对线性谐振子的研究具有重要意义.本文分别用配方法、微扰法求解出一维线性谐振子在恒定弱电场中的能量本征值,给出了求解在恒定弱电场中一维线性谐振子能级的两种典型方法.     

一种超声清洗电源频率跟踪技术

针对超声清洗过程中超卢换能器谐振频率发牛漂移的问题,设计了一种由D触发器、单片机、数字电位器和压控振荡器组成的频率跟踪系统。该系统利用单片机检测超声清洗电源负载的电压、电流的相位差,并通过数字电位器来改变压控振荡器的输山频率。与其它频率跟踪方法梢比,该系统降低了程序编写的复杂性,电路简单且易于实现。     

Increasing power efficiency in the design of a low power and low phase noise CMOS LC oscillator

This study developed a local oscillator (LO) with low phase noise and low power consumption. The proposed oscillator core comprises a pair of cross‐coupled transistors, which are fed by another pair of transistors that injects current at moments close to the peak of output voltage. The position of the current injection transistors, which are inserted in series with the cross‐coupled transistors, affects the waveform of current injected into an inductive–capacitive (LC) tank. Installing a capacitor on the source node of the cross‐coupled transistors increases the current injected into the LC tank and thereby augments the output voltage amplitude and power efficiency of the LO. The resonator phase shift and Q can be corrected by adjusting the source capacitance, which filters noise. These changes reduce the phase noise to ?123.4 dBc/Hz at a frequency offset of 1 MHz and improve oscillator performance with a figure of merit equal to ?193.5 dBc/Hz. To evaluate the LC tank, a 5 GHz LO was simulated at 1.8 V power supply and 2.5 mW power consumption. The simulation was conducted using a practical 0.18 complementary metal–oxide–semiconductor model manufactured by the Taiwan Semiconductor Manufacturing Company. The simulation results confirmed the analytical findings.     

基于信号预处理的杜芬振子弱信号检测方法

杜芬振子对周期信号极其敏感,对噪声具有较强免疫力,被研究用于强噪声背景下弱周期信号的检测及其各项参数的测量。为进一步提高杜芬振子检测含噪信号的性能,本文提出了先对待测信号预处理再送入杜芬振子的弱信号检测算法,并在理论上进行了证明。该方法先将待测信号分割、叠加、延拓再送入杜芬振子进行检测,仿真表明该方法在将信号分割成多段、叠加、延拓时可获得较大的信噪比增益,其中分割数目为3时,检测信噪比下限降低约为2 dB,分割数目为5时,检测信噪比下限降低约为3 dB。