Stability and morphology-dependence of Sc3+ ions incorporation and substitution kinetics within ZnO host lattice

In this study, sol–gel spin coating route was carried out to prepare Scandium doped ZnO thin films with different controlled percentage (1–7%). Particularly, it has been demonstrated, through original conjoint morphological-structural and optical investigations, that some interesting physical properties were induced. Indeed, X-ray diffraction (XRD) analysis shows that (002) preferential crystalline plane for Sc doped ZnO films was kept along with ZnO hexagonal würtzite structure, although Sc doping seemed to cause a decrease in crystallinity. Except for 1 at% Sc doping ratio, optical band gap changes reversely with Urbach energy with a decrease in optical gap and a broadening of the absorption tail. Ab-initio calculations of lattice dynamical properties outlined additional strong hybridization between Sc and O atoms and show the stability of Scandium doped ZnO.     

Investigations on the bifurcation of a noisy Duffing–Van der Pol oscillator

This study carried out investigations on the bifurcation characteristics of a Duffing–Van der Pol (DVDP) oscillator subjected to white noise excitations. Dynamical (or D-) bifurcations are characterised by dramatic changes in the dynamical behaviour leading to topological changes in the phase portrait. An additional mode of bifurcation - phenomenological (or P-) bifurcation, is observed in stochastically excited systems when the stationary joint probability density function of the state variables undergo topological changes in the probability space. While D-bifurcation analysis is quantified in terms of the sign changes in the largest Lyapunov exponent, P-bifurcation analysis is usually qualitative and through visual inspection. In this study, a new quantitative measure for P-bifurcations based on the Shannon entropy is proposed. A comparison of the parameter regimes of the noisy DVDP oscillator identified by the three bifurcation methodologies have been presented.     

A quadrature RC-oscillator with capacitive coupling

In this paper the capacitive coupling in quadrature RC-oscillators is investigated. The capacitive coupling has the advantages of being noiseless with a small area penalty and without increasing the power dissipation. The results show that a phase error below 1° and an amplitude mismatch lower than 1% are obtained with a coupling capacitance about 20% of the oscillator׳s capacitance value. Due to this kind of coupling, the phase-noise improves by 3 dB (to −115.1 dBc/Hz @ 10 MHz) and the increase of power requirement is only marginal leading to a figure-of-merit of −154.8 dBc/Hz. This is comparable to the best state-of-the-art RC-oscillators, yet the dissipated power is about four times less. We present calculations of frequency, phase error and amplitude mismatch that are validated by simulations. The theory shows that phase error is proportional to the amplitude mismatch, indicating that an automatic phase error minimization based on the amplitude mismatches is possible. The measurements on a 2.4 GHz voltage-controlled quadrature RC-oscillator with capacitive coupling fabricated in 130 nm CMOS circuit prototypes validate the theory.     

3MZ3216C球轴承沟道精研机振荡器的改进

针对3MZ3216C球轴承外圈沟道精研机振荡器球面连杆与轴承间产生间隙后影响产品质量且维修困难等问题,对振荡器结构进行了改进,使维修简单迅速,减少了停机时间,保证了产品质量。     

A time-domain digitally controlled oscillator composed of a free running ring oscillator and flying-adder

t supply voltages ranging from 0.6 to 1.2 V, and consumes 4 mW of power with 500 MHz frequency output at 1.2 V supply voltage.     

On the systematic synthesis of OTA-based Wien oscillators

A NAM expansion method for systematic synthesis of OTA-based Wien oscillators is given. Moreover, the NAM expansion method for four different classes of the oscillators is considered. The class I oscillators employ three OTAs, the class II oscillators employ four OTAs, the class III oscillators employ five OTAs, and the class IV oscillators employ six OTAs. Each class has 32 different forms, resulting in 128 Wien oscillators using OTAs. Having used grounded capacitors, the circuits are easy to be integrated and their parameters can be tuned electronically through tuning bias currents of the OTAs. The MULTISIM simulation results have been included to support the generation method.     

An Analytical Approximation for the Pull‐Out Frequency of a PLL Employing a Sinusoidal Phase Detector

The pull‐out frequency of a second‐order phase lock loop (PLL) is an important parameter that quantifies the loop's ability to stay frequency locked under abrupt changes in the reference input frequency. In most cases, this must be determined numerically or approximated using asymptotic techniques, both of which require special knowledge, skills, and tools. An approximating formula is derived analytically for computing the pull‐out frequency for a second‐order Type II PLL that employs a sinusoidal characteristic phase detector. The pull‐out frequency of such PLLs can be easily approximated to satisfactory accuracy with this formula using a modern scientific calculator.     

High-power microwave generation by double-anode virtual cathode oscillator

The virtual cathode oscillator (vircator) is one of the promising devices to oscillate high-power microwaves. Simplicity and high-power capability are advantages. However, the low efficiency and frequency stability are serious problems. In this article, we dealt double anode to strengthen the microwave interactions. The measurement result shows that the output of the virtual cathode oscillator can be progress by using the double-anode.     

3mm波段集成振荡器研究

描述了一种3mm波段集成振荡器,该振荡器由雪崩二极管、微带谐振器、阻抗匹配器、鳍线过渡组成.通过对3mm波段集成振荡器进行理论分析和实验研究,最终在国内首次采用3mm连续波雪崩二极管成功研制出微带集成振荡器,工作频率为94.78GHz,输出功率大于7mW.