Robust semiglobal swarm tracking of coupled harmonic oscillators with input saturation and external disturbance

The robust semiglobal swarm tracking problem of N coupled harmonic oscillators and 1 actual leader with input saturation and external disturbance on a directed communication topology is considered, in which the N coupled harmonic oscillators are referred to followers. First, the low‐and‐high gain feedback technique is introduced to construct a relative state‐dependent control algorithm. Then, an observer‐based control algorithm is designed based on the low‐and‐high gain feedback technique and the high‐gain observer design methodology. Sufficient conditions are derived to guarantee robust semiglobal swarm tracking for state‐feedback control and output‐feedback control, respectively. Numerical simulations are finally provided to verify the theoretic results.     

Pinning Cluster Synchronization of Coupled Nonidentical Harmonic Oscillators Under Directed Topology

This paper addresses cluster synchronization of coupled harmonic oscillators over directed fixed and switching topologies, where uncoupled harmonic oscillators in the same cluster have the identical node dynamics, while any pair of nodes in different clusters are essentially distinguishing according to their local dynamics. A pinning control protocol is proposed for such coupled harmonic oscillators system, and then some graphic topology conditions easy to verify are established for cluster synchronization. The main contributions of the present investigation include: (i) cluster synchronization problem of coupled nonidentical harmonic oscillators is addressed over directed topology; (ii) desynchronizing motion of harmonic oscillators from different clusters doesn't depend on negative coupling weights but leader of every cluster; (iii) this paper deals with what kind of harmonic oscillators ought to be pinned in order to reach cluster synchronization. Finally, numerical examples and simulations demonstrate the obtained theoretical results.     

两个耦合Van der Pol振子系统的一阶近似守恒量

用直接积分法计算两个耦合Van der Pol振子系统的一阶近似守恒量,将两个耦合Van der Pol振子系统看成是未受微扰系统与微扰项的迭加,先通过坐标变换将未受微扰系统解耦,并对解耦系统的3种可能状态进行讨论,得到未受微扰系统的13个精确守恒量,再考虑微扰项对精确守恒量的影响,运用一阶近似守恒量的性质,得到1个稳定的一阶近似守恒量.另外,由13个精确守恒量直接得到13个平凡的一阶近似守恒量.     

Synchronization of electrochemical oscillators of S-NDR type

Electrochemical oscillators are classified as truly potentiostatic or Negative Differential Resistance (NDR) type considering, respectively, the nonessential or essential role of double-layer potential on the dynamics. NDR type oscillators are further grouped into N-NDR and S-NDR type systems where N and S refer to the characteristic shape of the polarization curve. Here, we report on the effect of global coupling on the dynamics of interacting electrochemical oscillators of S-NDR type where the electrode potential acts as an essential negative feedback variable. The Lee-Jorné scheme has been applied to model Zn electrodeposition on two or an array of 128 globally coupled nonidentical electrodes. The strength of global coupling between the electrodes can be systematically varied by changing collective and individual resistors in the circuit. Several different scenarios for synchronization and partial synchronization have been observed and analyzed. The collective dynamics is characterized by an order parameter, the average phase shift between the oscillators, and phase portraits based on Hilbert transform. The effect of changing the double-layer capacitance on the dynamics is also explored.     

8.64-11.62 GHz CMOS VCO and divider in a zero-IF 802.11a/b/g WLAN and Bluetooth application

A fully integrated VCO and divider implemented in SMIC 0.13-μm RFCMOS 1P8M technology with a 1.2 V supply voltage is presented.The frequency of the VCO is tuning from 8.64 to 11.62 GHz while the quadrature LO signals for 802.11a WLAN in 5.8 GHz band or for 802.11b/g WLAN and Bluetooth in 2.4 GHz band can be obtained by a frequency division by 2 or 4,respectively.A 6 bit switched capacitor array is applied for precise tuning of all necessary frequency bands.The testing results show that the VCO has a phas...     

High-power continuous-wave operation of a fiber optical parametric oscillator in L and U bands

Fiber optical parametric oscillators (OPOs), based on a highly-efficient four-wave mixing process in a χ⁽³⁾ medium, are reviewed. Their capability to provide very large tuning ranges with high output power is discussed. A novel architecture for CW fiber OPOs is presented, which has allowed us to significantly extend the performance of these devices. To do so we used: (i) a highly-nonlinear fiber (HNLF) as the parametric gain medium; (ii) a narrowband tunable intracavity filter; (iii) a high output coupling fraction from the feedback loop (up to 3 dB). With these features, we have been able to obtain excellent performance in terms of output power and tuning range, even with a reduced pump power. With only about 2 W of pump power, we have obtained the following performances: (i) tuning range of 254 nm; (ii) output power in excess of 1 W at some wavelengths; (iii) external conversion efficiency in excess of 60% at some wavelengths; (iv) linewidth as low as 8 GHz.This architecture of fiber OPO can be used for providing narrow linewidth tunable high-power CW radiation over hundreds of nanometers. Such sources could find applications in remote sensing, optical communication, nonlinear optics, etc.     

Chaotic Oscillators Derived from Sinusoidal Oscillators Based on the Current Feedback Op Amp

A collection of novel chaotic oscillators displaying behavior similar to that of the chaotic Colpitts oscillator and requiring the same number and type of energy storage elements is proposed. The oscillators use as an active element the current feedback op amp (CFOA) mostly employed as a current negative impedance converter (INIC). Nonlinearity is introduced through a two-terminal voltage-controlled nonlinear device with an antisymmetric driving-point characteristic. The chaos generators are designed based on sinusoidal oscillators that have been modified for chaos in a semi-systematic manner. By using CFOAs, several attractive features are attained, in particular suitability for high frequency operation. Systems of third- and fourth-order ordinary differential equations describing the chaotic behaviors are derived. Experimental results, PSpice circuit simulations and numerical simulations of the derived mathematical models are included.     

经典极限下量子卡诺热机经济最优性能

根据现代非平衡统计理论和有限时间经济分析法，研究受热漏影响的谐振子系统量子卡诺热机在经典极限下的经济最优性能．得到了量子热机的最大利润率以及对应的最佳功率和效率．所得结论对实际热机的优化设计有一定指导意义     

用于铷频标频率综合器中的可变分频器

对用于铷频标频率综合器中的可变分频器进行了设计、介绍了可变分频器的改进、实验结果表明，该频综器的性能指标满足要求。     

Time Domain Verification of Oscillator Circuit Properties

The application of formal methods to analog and mixed signal circuits requires efficient methods for constructing abstractions of circuit behaviors. This paper concerns the verification of properties of oscillator circuits. Generic monitor automata are proposed to facilitate the application of hybrid system reachability computations to characterize time domain features of oscillatory behavior, such as bounds on the signal amplitude and jitter. The approach is illustrated for a nonlinear tunnel-diode circuit model using PHAVer, a hybrid system analysis tool that provides sound verification results based on linear hybrid automata approximations and infinite precision computations.