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为了扩展光电振荡器(OEO)的频率范围,设计了 一种基于载波相移系统的二倍频OEO(FD-OEO)。 系统采用相位调制器(PM)和Mach-Zehnder调制器(MZM)并联,构成载波相移系统,利用载 波相移双边带(CPS-DSB) 调制的方法产生二次谐波分量;同时利用啁啾光纤布拉格光栅(CFBG)色散特性实现边带分 量与CPS补偿,维持 OEO环路中基频信号的振荡。实验结果显示,在OEO环路系统基频信号为2.23GHz情况下,产生了4.30 GHz的FD信号,且通过边模抑制性能、稳定性及相位噪声对系统性能进行了验证。 相似文献
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介绍简谐振子的工作原理。利用ANSYS软件,采用有限元法创建了简谐振子质量块的实体模型,选择单晶硅作为简谐振子中质量块的材料;设置了模型的材料属性,采用智能分网的方式对模型划分网格,并对质量块模型施加沿x轴水平方向载荷,进行三维的静力分析和模态分析。静力分析得到实体模型的总位移是0.236×10-19μm;模态分析时只对前四阶模型进行了分析,根据其振型图及其总位移的应力云图,得到实体模型的二十阶振动模态的频率是78 001Hz,二十阶的总位移是0.122×10-6μm。 相似文献
14.
The stability of a linear oscillator with delayed state feedback driven by parametric Gaussian white noise is studied in this paper. The first and second order moment equations of the system response are derived by using moment method and Itô differential rule. Based on the moment equations, the delay-independent stable conditions of both moments are proposed: For the first order moment, the sufficient and necessary condition that guarantee delay-independent stability is identified to that of the deterministic system; for the second order moment, the sufficient condition that ensure delay-independent stability depends on noise intensity. The theoretical results are also illustrated with numerical simulations. 相似文献
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W. H. Steeb 《中国工程学刊》2013,36(6):717-720
Abstract The chaotic behaviour of the sinusoidally driven nonlinear circuit proposed by Hunt is investigated. The results are compared with those from other driven nonlinear circuits. 相似文献
18.
Efficient generation of sub-millimetre microbubbles was recently made possible by pulsating the flow of gas supplied into a parallel-exits aerator, using a fluidic oscillator for the purpose. Without moving parts, it can generate oscillation at high frequency, an important factor due to bubble natural frequency rapidly increasing with the desirable decrease of their size. This paper discusses development of an unusual oscillator – a part of an integral oscillator/aerator unit – capable of generating a particularly high driving frequency, in the kilohertz range, in a layout that promotes a strong third harmonic frequency of the basic oscillation. 相似文献
19.
In this paper, a promising heat engine technology capable of utilizing low grade heat is examined. Based on a two-phase thermofluidic oscillator concept, the novelty and advantage of this particular system lie in its use of phase change and its lack of reliance on inertia to sustain oscillations, though it is recognized that inertia will always be present in any physical manifestation of the engine. The system is analysed using lumped linearized one-dimensional network models, both with and without inertia, based on thermoacoustic principles and extending these to account for phase change. The gain (temperature difference between source and sink heat exchangers) and frequency at which marginal stability (desirable continuous oscillations) can be achieved is calculated. The effects of the load resistance (fluid drag) and fluid inertia, as well as of the flow resistance due the feedback valve on the marginal stability gain, frequency and exergetic efficiency of the system are investigated. It is found that an increase in feedback resistance leads to a need for a higher gain for oscillatory behaviour to be achieved. In addition, even though an increase in either the resistance or inertia in the load, or the feedback resistance at low values of these variables has almost no effect on the required gain and the oscillation frequency of the system, an increase in these variables can lead at higher values to increased gains and reduced frequencies. A reduced feedback resistance and greater load inertia can also lead to considerably higher efficiencies, while increasing the load resistance allows for an increase in efficiency until a maximum is reached, after which the efficiency decreases again. The validity of certain approximations made previously is considered, and it is shown that these must be made with care. The results from this study can be used for the improved design and optimization of such oscillators, and similar systems. 相似文献
20.
A new mathematical method is proposed to convert the oscillator instability parameters from Allan variance to Spectrum Density(SD)of random phase fluctuations,which is the inversion of the classic transformation formula from SD to Allan variance.Due to the fact that Allan variance does not always determine a unique SD function,power-law model of the SD of oscillator phase fluctuations is introduced to the translating algorithm and a constrained maximum likelihood solution is presented.Considering that the inversion is an ill-posed problem,a regularization method is brought forward in the process.Simulation results show that the converted SD of phase fluctuations from Allan variance parameters agrees well with the real SD function.Furthermore,the effects of the selected regularization factors and the input Allan variances are analyzed in detail. 相似文献