Papers by Keyword: Oscillator

Abstract: The oscillatory behaviors of an oscillator made from double-walled carbon nanotubes (DWCNTs) with vacancy defects were systematically investigated via molecular dynamics simulation method. We found that the vacancy defects change the off-axial rocking motion and the van der Waals potential, resulting in more energy dissipation. Unlike the case in the C60–nanotube oscillators (Song, et al., Phys. Lett. A. 373 2009, 1058-1061) that one vacancy can make the oscillators more stable, our study showed that the vacancies cannot improve the performance of DWCNT-based oscillators no matter where vacancy defects are located.

Abstract: According to the requirement of the vehicle-mounted radar and taking into consideration of main circuit, amplifying circuit, waveform conversion circuit, automatic gain circuit and voltage control circuit, and other factors of the AT-cut quartz crystal resonator. We designed a small single layer constant temperature high stability crystal vibration for vehicle-mounted radar.

Abstract: In this paper, SimpleC algorithm and Realizable turbulence model are applied to simulate the detailed flow field of oscillator, which is the key component of the vertical drainage jet flowmeter. Based on analyzing the pressure fluctuation of fluid in the feedback channels of the oscillator at different flowrates, the results indicate that there is an obviously linear relationship between velocity and oscillation frequency of static pressure in the vertical feedback channels within a certain range of flowrate. The achievements can be helpful to the optimization the design of vertical drainage jet flowmeter.

Abstract: Based on the CMOS technology, the sawtooth wave oscillator used in switching power supply is designed. In the condition of 27 °C and 4 V power supply voltage, the oscillation frequency of sawtooth wave oscillator is 246.61 KHz. The oscillation frequency of sawtooth wave oscillator changes between 245.94 KHz and 247.89 KHz when the power supply voltage changes between 3V and 6V. The maximum deviation is ±0.52%. From the experimental results, the sawtooth wave oscillator has good linearity, the effect of temperature and power supply to the oscillation frequency of sawtooth wave oscillator is very little. The CMOS sawtooth wave oscillator is suitable for switching power supply.

Abstract: This paper presents the simulation and testing of Vibration-to-Electrical Power Generators (VEPG) with different kinds of permanent magnet oscillators for scavenging ambient vibrations. The finite element method is used for magnetic fields calculation. Firstly, single permanent magnet type oscillators are simulated under the sinusoidal vibration. The calculation results show that the permanent magnet oscillator with diameter 20 mm and height 5 mm will realize 4 V peak-peak voltage. Secondly, multiple permanent magnets type oscillators are simulated under the same vibration and comparative studied with the single permanent magnet type. The results show that multiple permanent magnets oscillator with suitable structure will dramatically improve the power density of VEPG. By the end, prototypes with different kinds of oscillators are tested on the condition of sinusoidal vibration. And the experimental results agree well with the simulation ones.

Abstract: This paper mentioned the design of an isolated feedback generator with SOI process. This generator adopts 40V SOI technology and it integrates reference, high frequency oscillator, error amplifier and modulator, meanwhile this generator predigests the mission of designing for the closed loop feedback of the switching power supply which types are the isolated and primary controlled. Along with the developing of the power conversion, this circuit is specially designed for high reliability, high capability and anti-radicalization applications.

Abstract: This paper presents an digital microwave oscillator which employs a phase lock loop (PLL) chip and a direct digital synthesizer (DDS) chips to realize a pure frequency at 3.417GHz (half of the ⁸⁷Rb atom ground-state hyperfine transition frequency) for the coherent population trapping (CPT) atomic clock application. And at this frequency, the oscillator demonstrates low noise (lower than-50dBc/Hz@100Hz and lower than-55dBc/Hz@1kHz) and purity. Moreover, based on the communication between a computer and the MCU, this oscillator could be completely controlled by self-developed user interface.

Abstract: This paper presents a time-domain CMOS oscillator-based temperature sensor with one-point calibration for test cost reduction. Compared with the former CMOS sensors with linear delay lines, the proposed work composed of a temperature-to-pulse generator with adjustable time gain and a time-to-digital converter (TDC) can achieve lower circuit complexity and smaller area. A temperature-dependent oscillator for temperature sensing was used to generate the period width proportional to absolute temperature (PTAT). With the help of calibration circuit, an adjustable-gain time amplifier was adopted to dynamically adjust the amplified width that was converted by the TDC into the corresponding digital code. After calibration, the fluctuation of the sensor output with process variation can be greatly reduced. The maximum inaccuracy after one-point calibration for six package chips was 1.6 °C within a 0 80 °C temperature range. The proposed sensor fabricated in a 0.35-μm CMOS process occupied a chip area of merely 0.07 mm², achieved a fine resolution of 0.047 °C/LSB, and consumed a low power of 25 μW@10 samples/s.

Abstract: We present three oscillator designs using the negative-differential-resistance (NDR) circuit which is composed of several Si-based metal-oxide-semiconductor field-effect transistor (MOS) devices and one SiGe-based heterojunction bipolar transistor (HBT) devices. These oscillator circuits are composed of the NDR circuit, resistor, inductor, and capacitor. The oscillation frequencies are about several GHz based on the HSPICE simulation results. The circuits are designed using a standard 0.18 μm BiCMOS technique. Because our circuits are mainly made of a BiCMOS-NDR circuit that is different from a tradition NDR device made by a resonant tunneling diode with a quantum-well structure, we can utilize the nanobased BiCMOS process to implement these circuits by further improving the parameters.

Abstract: A mathematical modal for a new oscillator under Gravity is gived by The Second Law of Neton and proved the correctness by The Energy Method .We obtained a equation for the equilibrium point of system by the definition .We observe the dynamics action by the Hamilton function.Meanwhile the phase trajectories and the Poincaré sections are also presented. The analysis shows the complicated nonlinear dynamics with periodic motion in some special case.