Optimization analysis on the bandwidth algorithm for the phase-locked loop (PLL) in OTU

The bandwidth of phase-locked loop (PLL) in optical transponder unit (OTU) is affected by both the external input jitter and the internal phase noise jitter, so the selection for the bandwidth of the PLL has a contradiction and it is necessary that the bandwidth is optimally designed. Under the consideration of both the external input jitter and the internal phase noise, the bandwidth algorithm of the PLL is comprehensively analyzed, and the optimization algorithm of the bandwidth for the PLL of the OTU can be deduced and obtained through improving the former calculation and analytical methods. The optimal bandwidth of the PLL has been analyzed and obtained so as to ensure that the clock output of the OTU has a lower jitter noise. And then the optimization algorithm is applied in 2.5 Gbit/s and 10 Gbit/s OTU, the optimal parameters of the PLL and the output jitter value of the OTU have been acquired by taking the quantitative and qualitative analysis of the PLL parameters. The study shows the optimization algorithm is superior and feasible as well as it is better used in the OTU and plays an important part in the practical application.     

Energy-based analysis of frequency entrainment described by van der Pol and phase-locked loop equations

This paper analyzes frequency entrainment described by van der Pol and phase-locked loop (PLL) equations. The PLL equation represents the dynamics of a PLL circuit that appear in typical phase-locking phenomena. These two equations describe frequency entrainment by a periodic force. The entrainment originates from two different types of limit cycles: libration for the van der Pol equation and rotation for the PLL one. To explore the relationship between the geometry of limit cycles and the mechanism of entrainment, we investigate the entrainment using an energy balance relation. This relation is equivalent to the energy conservation law of dynamical systems with dissipation and input terms. We show response curves for the dc component, harmonic amplitude, phase difference, and energy supplied by a periodic force. The obtained curves indicate that the entrainments for the two equations have different features of supplied energy, and that the entrainment for the PLL equation possibly has the same mechanism as does the regulation of the phase difference for the van der Pol equation.     

Evaluation of Properties and Structural Transitions of Poly-L-lysine: Effects of pH and Temperature

Abstract

The structural response to temperature and pH changes of poly-l-lysine (PLL) has been studied by a variety of experimental methods including turbidimetry, dynamic light scattering, and Zeta potential analysis. The experimental results and the molecular dynamics simulations showed that the PLL structural transitions were a result of a competition between electrostatic repulsion, which promotes an extended state, and the hydrophobic effect, which favors a compact state. In fact, as the pH was decreased, the PLL conformation changed from α-helix to the random coil and the hydrophilic volume increases resulted in a transition to spherical micelles which then swelled due to charge-charge repulsions. Following a rise in temperature and/or at high pH, PLL undergoes the α-helix-to-β-sheet transition and reacted more rapidly to form hydrophobic aggregates.     

Signal design using nonlinear oscillators and evolutionary algorithms: application to phase-locked loop disruption

This work describes an approach for efficiently shaping the response characteristics of a fixed dynamical system by forcing with a designed input. We obtain improved inputs by using an evolutionary algorithm to search a space of possible waveforms generated by a set of nonlinear, ordinary differential equations (ODEs). Good solutions are those that result in a desired system response subject to some input efficiency constraint, such as signal power. In particular, we seek to find inputs that best disrupt a phase-locked loop (PLL). Three sets of nonlinear ODEs are investigated and found to have different disruption capabilities against a model PLL. These differences are explored and implications for their use as input signal models are discussed. The PLL was chosen here as an archetypal example but the approach has broad applicability to any input∕output system for which a desired input cannot be obtained analytically.     

Regeneratively mode-locked fiber laser with a repetition rate stability of 4.9x10-15 using a hydrogen maser phase-locked loop

We demonstrate an ultrastable regeneratively mode-locked fiber laser that employs a phase-locked loop (PLL) circuit with a hydrogen maser. The stability for an integration time of 1s was 6.2x10(-13), which is 16 times better than that of a conventional PLL laser. For an integration time of 1000s, the stability reached as high as 4.9x10(-15). The repetition-rate stability was limited by the synthesizer used for the PLL operation, and there was no additional fluctuation induced by the laser operation.     

Noisy fringe pattern demodulation by an iterative phase locked loop

The phase locked loop (PLL) technique applied to demodulate two-dimensional carrier-frequency fringe patterns has been developed recently. Here we present an extension to the basic PLL scheme to demodulate noisy fringe patterns. This modified technique estimates the phase in the fringe pattern iteratively; that is, the first wavefront estimation is done using a flat reference phase and the second iteration takes the demodulated phase found in the first iteration as the new reference. The third demodulating iteration uses the second phase estimation as the reference and so on, until further changes in the detected wavefront fall below a predefined threshold. During the iterative process the bandwidth of the iterative PLL system is gradually decreased to improve the signal-to-noise ratio of the detected phase as well as to resolve noise-generated phase inconsistencies.     

彩色图像实时采集的硬件设计

本文分析了不同图像信号源的特点,提出了彩色图像数据采集的硬件设计方案。论述了数字化参数的选择原则。较详细地分析了所设计的两种锁相环电路：以彩色同步为基准的单片锁相环和以行频ｆＨ 为基准的锁相环。两种锁相环产生的时钟信号分别适合于标准信号和非标准信号。最后简述了帧存贮体和接口设计。本文提出的实时采集方案具有硬件少、软件简单、调试容易等优点     

直流电机的数字同步锁相

在某高速摄影机中,我们采用了同步数字锁相环路,本文叙述该机中直流电机的数字同步锁相原理及其所用数字相位误差积分器线路的构成。     

Properties of Optical Phase-Locked Loop Based on Four Wave Mixing in Semiconductor Laser Amplifiers

In this paper, the properties of the optical phase-locked loop(PLL) based on the four-wave mixing in the semiconductor laser amplifiers (SLAs) are discussed. The components that achieve the function of detecting the bit phase of the input optical signal are concerned and discussed in detail together as a function module named as the optical bit phase detector referred to the general electronic PLL. Therefore, most of the properties of the optical PLL can be analyzed by applying the general phase-locked theory. Here the stability of the optical PLL is discussed. It's shown that the variance of input signal power in the practical application will cause optical PLL system unstable because of its long loop delay. The influence on the output phase jitter of the optical PLL is also investigated.     

多聚赖氨酸诱导的负电性磷脂巨囊泡形变

利用荧光显微技术表征了多聚赖氨酸诱导的负电性磷脂巨囊泡的动力学响应行为.研究发现,多聚赖氨酸可吸附至二油酰磷脂酰胆碱和二油酰磷脂酸混合磷脂巨囊泡的表面,诱导其发生粘连、出"绳"及破裂现象.分析认为,在低盐环境中,膜形变由多聚赖氨酸吸附于二油酰磷脂酸富集区引起的膜两叶应力不对称,以及静电相互作用等因素产生.研究结果对基于聚合物-巨囊泡体系的药物输运控释、细胞形变、微控反应和基因治疗等方面的研究提供有价值的支持.