Suppression of overtone oscillation and low‐current operation using novel‐design scheme for quartz crystal oscillators

A novel design is proposed for a low‐frequency quartz crystal oscillator circuit. Negative resistance in a low‐frequency CMOS‐inverter quartz oscillator was reviewed for the fundamental mode at 32 kHz and the overtone oscillation at 200 kHz. Suppression of the overtone oscillation, appropriate gain, and drive current reduction are realized by adding only three circuit components. Experimental results and an estimate of the absolute value of the negative resistance are presented for the conventional Colpitts circuit and two types of the quartz crystal oscillator circuit. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

石英晶体振荡器负载电容的匹配设计

介绍了石英晶体振荡器的结构和主要参数、负载电容的匹配设计和电路负阻的测量计算,以及晶体驱动功率的测量计算。针对实际应用中因谐振阻抗不匹配而出现的振荡电路不起振、频率偏差较大等现象,优化设计了基于舰用断路器电量监测模块实际应用的晶体振荡电路。     

车载雷达用恒温石英晶体振荡器设计

根据车载雷达的需要，利用AT切石英晶体谐振器从主振电路、辐度放大电路、波形变换电路、自动增益电路和压控电路等诸多因素综合考虑，设计了车载雷达用的小型单层恒温高稳晶振，具有良好的老化特性和高可靠性。     

Four‐segment oscillator circuit for piezoelectric sensing devices

Novel circuit design is proposed for a low‐frequency quartz crystal oscillator circuit that consists of four segments. The characteristics of the negative resistance in a low‐frequency Complementary Metal Oxide Semiconductor (CMOS)‐inverter quartz oscillator were reviewed for the two modes of SC (stress‐compensated) cut mode and the overtone of low‐frequency mode; separation of two modes and suppression of overtone oscillation were demonstrated successfully. Experimental results and an estimate of the absolute value of the negative resistance are presented for the four‐segment oscillator circuit and the conventional Colpitts circuit and two new types of oscillator circuits. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

QMEMS晶振的MEMS器件真空度测量方法研究

QMEMS晶振是一种采用MEMS(micro-electro-mechanical system)加工技术充分发挥石英(Quartz)晶体材质特性制造出的高性能、高集成度的新型石英晶振。利用QMEMS晶振体积小、性能稳定的特点,提出将QMEMS晶振作为传感器内置于MEMS器件管壳内部,对MEMS器件腔体内部真空度进行实时监测的方法。在对石英晶振测量真空原理进行分析的基础上,研究了QMEMS晶振的结构和管壳开口方法,设计了一套基于QMEMS晶振气压传感器的真空度测量系统,实现了对真空度的测量,并对系统进行了标定。试验表明,该真空计可实现1~30kPa压强范围的测量,测量精度约为5%,能满足MEMS器件实时真空度测量要求。     

三相BUCK型SVPWM整流器LC振荡阻尼混合控制

为了抑制电流型PWM整流器输入侧LC滤波器谐振引起网侧电流畸变和系统振荡,提出了一种采用有源阻尼控制和改进SVPWM技术结合的控制策略。采用虚拟谐波阻尼器的有源控制策略,在控制过程中增加虚拟的等效阻尼电阻,能够在不改变基波功率流动的前提下抑制LC谐振引起的畸变和振荡。分析BUCK型PWM整流器的数学模型,比较无源阻尼和有源阻尼控制优缺点,在采用改进SVPWM的BUCK型整流器中引入有源阻尼补偿器。仿真和实验结果表明,所提出的控制方法能够有效地减小线电流畸变,改善系统稳定性,具有一定的工程实用价值。     

A 5‐MHz AT‐cut quartz crystal oscillating circuit functioning in 350 nA

An oscillating circuit functioning at ultra low power (350 nA) for a 5‐MHz AT‐cut quartz crystal oscillator was investigated. This circuit has a resistance between the power terminal of the CMOS‐IC and the power supply, and another between the earth terminal of the CMOS‐IC and the ground (GND). These resistances discourage an inrush of current, and set a gain (g_m) necessary for oscillating the circuit at minimum. The developed circuit is quite simple, but enables driving at once‐unthinkable, low power (below 1 µA). © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

一种单片高稳振荡器芯片设计

针对传统Pierce振荡器改进了振荡器的起振电路结构,采用负阻起振理论基于0.35μm CMOS工艺设计了一种单片高稳振荡器芯片。芯片主要包含起振电路、缓冲器电路、驱动电路、使能电路及分频器电路,输出频率范围为4 MHz^30 MHz可调,应用cohesion及Hspice软件完成了电路设计与仿真,使用Cadence软件进行了芯片的版图设计,LVS验证后完成了芯片的后仿真工作,仿真结果表明在设定的6种晶体参数下,电路在800μs时完成了起振且在tt、ff、ss 3种模式下输出平稳,该芯片能适用于无线收发信机中。     

Transformer‐coupled π‐network differential CMOS oscillator circuit topology

This paper reports a novel oscillator circuit topology based on a transformer‐coupled π‐network. As a case study, the proposed oscillator topology has been designed and studied for 60 GHz applications in the frame of the emerging fifth generation wireless communications. The analytical expression of the oscillation frequency is derived and validated through circuit simulations. The root‐locus analysis shows that oscillations occur only at that resonant frequency of the LC tank. Moreover, a closed‐form expression for the quality factor (Q) of the LC tank is derived which shows the enhancement of the equivalent quality factor of the LC tank due to the transformer‐coupling. Last, a phase noise analysis is reported and the analytical expressions of phase noise due to flicker and thermal noise sources are derived and validated by the results obtained through SpectreRF simulations in the Cadence design environment with a 28 nm CMOS process design kit commercially available. Copyright © 2016 John Wiley & Sons, Ltd.     

基于调节振荡频率的脉冲占空比测量

脉冲占空比是反映脉冲信号的一个基本参数,在电子测量中占有重要地位。本文设计了一种利用可调频率振荡电路校准,基于电子计数的脉冲信号占空比的测量电路。该电路采用基本数字电路组合,以数字显示形式直接给出脉冲信号的占空比。通过Multisim仿真验证测量电路能够按照预先设计的方案对脉冲信号占空进行有效的测量,调节简便,测量结果可靠,对50Hz～10kHz范围内的脉冲信号测量的误差一般不超过2%,能较好地满足测量要求。     

振荡电路式 LVDT 测量系统设计

针对传统 LVDT 测量电路中高成本模块较多且性能不足的问题,提出并设计了一种基于振荡电路的 LVDT 测量系统。 测量系统将 LVDT 线圈作为谐振电感接入高性能 LC 振荡器,利用其谐振信号的频移获得待测位移,借助谐振器数学模型及理 论分析改善测量系统线性度。 样机实验结果显示,在满位移状态下频率范围可达到 73 ~ 122 kHz,采样速率和分辨率可根据实 际需求进行调整,其最高分辨率可达到 16. 7 bits,实现亚微米级测量,此时采样速率为 200 Sps,非线性误差为 0. 14%FS。 与传 统电桥方法相比,该测量系统综合性能更优,且无需低失真激励及高精度解调模块,在电路成本和尺寸方面具有显著优势。     

一种新的CAN总线位填充方案

针对CAN总线原5位填充模式的缺陷,提出了一种新的10位填充模式.新模式从CAN总线的位定时、位填充及振荡器容差的约束关系入手,基于石英晶体振荡器,不改变现有的位定时寄存器容量.新的位填充模式仅需在原CAN控制器进行简单的软件升级即可实现,提高了数据传输效率和CRC校验可靠性.     

分布电感对石英晶体测试精度的影响及补偿

IEC推荐的石英晶体电参数的(网络零相位测试方法依赖于对测试环境的严格限制来保证其测试精度。在实际应用中,生产现场的测试环境将引入杂散电抗并严重影响其测试精度.为提高测量精度,根据石英晶体的电参模型和理想网络与实际网络模型的差异,理论和实验分析了分布电感对石英晶体谐振频率测试精度的影响,采用电容补偿的方法可以显著减小这一影响。实验结果表明,经过补偿后的石英晶体串联谐振频率的测量精度可达到±2×10~(-6)。     

Survey of integrated‐circuit‐oscillator phase‐noise analysis

This tutorial distills the salient phase‐noise analysis concepts and key equations developed over the last 75 years relevant to integrated circuit oscillators. Oscillator phase and amplitude fluctuations have been studied since at least 1938 when Berstein solved the Fokker–Planck equations for the phase/amplitude distributions of a resonant oscillator. The principal contribution of this work is the organized, unified presentation of eclectic phase‐noise analysis techniques, facilitating their application to integrated circuit oscillator design. Furthermore, we demonstrate that all these methods boil down to obtaining three things: (1) noise modulation function; (2) noise transfer function; and (3) current‐controlled oscillator gain. For each method, this paper provides a short background explanation of the technique, a step‐by‐step procedure of how to apply the method to hand calculation/computer simulation, and a worked example to demonstrate how to analyze a practical oscillator circuit with that method. This survey article chiefly deals with phase‐noise analysis methods, so to restrict its scope, we limit our discussion to the following: (1) analyzing integrated circuit metal–oxide–semiconductor/bipolar junction transistor‐based LC, delay, and ring oscillator topologies; (2) considering a few oscillator harmonics in our analysis; (3) analyzing thermal/flicker intrinsic device‐noise sources rather than environmental/parametric noise/wander; (4) providing mainly qualitative amplitude‐noise discussions; and (5) omitting measurement methods/phase‐noise reduction techniques. Copyright © 2013 John Wiley & Sons, Ltd.     

微波测距仪计数频率漂移控制方法

从微波测距仪相位法测距和自动数字测相原理出发,分析了微波测距仪计数频率漂移对测距精度的影响,得出了计数时钟的频率出现漂移时,对微波测距仪的测距精度将造成较大的影响,形成了计数时钟频率漂移误差。针对这种误差设计了一种基于单片机的频率校准电路,通过反馈原理提高了晶体振荡器输出频率稳定性,稳定了计数时钟频率,达到减小计数时钟频率漂移误差的目的。实测数据表明：控制电路有效控制了频率漂移,提高了微波测距仪的测距精度。     

温度控制电路

通过设计石英晶体振荡器中的恒温控制电路,提出用软性开关实现的桥式差分比较控温方案,并介绍其温控灵敏度的计算.     

电子式互感器合并单元同步时钟模块的设计

利用全球定位系统（Global Positioning System,GPS）时钟信号和晶振时钟信号精度互补的特点,提出了一种利用GPS时钟同步晶振时钟的新方法。采用除法电路和余数分摊的策略进行误差校正,使采样脉冲均匀准确,进一步减小各合并单元提供的采样脉冲之间的同步误差,同时在GPS时钟丢失时能减小积累误差,保持更长时间的同步。软件仿真和硬件实验均证明此方法的有效性。     

Temperature‐frequency characteristics simulation of piezoelectric resonators and their equivalent circuits based on three‐dimensional finite element modelling

The electromechanical resonators made of piezoelectric crystals such as a quartz crystal are widely used for electronic devices. Their frequency–temperature characteristics are of primary importance for their applications to the frequency control devices. The present paper demonstrates numerical simulation for several types of resonators using 3‐D Finite Element Modelling. The results are compared with the theoretical values whenever they are available. As they are electronic devices, the equivalent circuit representation is often favourable for describing the admittance at the electrical terminals which enables the circuit analysis including the effect of the temperature change by using commercially available circuit simulators. Copyright © 2003 John Wiley & Sons, Ltd.     

Phase noise analysis in CMOS differential Armstrong oscillator topology

This paper reports a phase noise analysis in a differential Armstrong oscillator circuit topology in CMOS technology. The analytical expressions of phase noise due to flicker and thermal noise sources are derived and validated by the results obtained through SpectreRF simulations for oscillation frequencies of 1, 10, and 100 GHz. The analysis captures well the phase noise of the oscillator topology and shows the impact of flicker noise contribution as the major effect leading to phase noise degradation in nano‐scale CMOS LC oscillators. Copyright © 2016 John Wiley & Sons, Ltd.     

基于PC声卡的超低频函数信号发生器的设计

利用Mathematica软件,通过计算机声卡外接简洁合理的电路,将计算机强大的运算功能与直接数字式频率合成（DDS）技术的基本思想相结合,设计了一种超低频函数信号发生器。信号的频率、幅值和相位都可以通过键盘实现数控无级步进,频率稳定度与晶振在同一数量级,能写出数学表达式或给出数列值的信号都可以产生,是真正的函数信号发生器,无需切换波段,最大频率范围0．005Hz～10kHz,最大输出信号20Vpp,并能实现功率输出。