For anti-jamming and anti-countermeasure techniques of the sonar receiver, the response characteristics of the automatic gain control （AGC） circuit and the survivability of the prime circuit under strong interferenc...For anti-jamming and anti-countermeasure techniques of the sonar receiver, the response characteristics of the automatic gain control （AGC） circuit and the survivability of the prime circuit under strong interference are analyzed by simulations and experiments. An AGC simulation model based on the voltage control amplifier VCA810 prototype is proposed. Then static and dynamic simulations are realized with single frequency signal and linear frequency modulated （LFM） signal commonly used in the active sonar. Based on intense sound pulse （ISP） interference experiments, the real-time response characteristics of each module of the receiver are studied to verify the correctness of the model as well as the simulation results. Simulation and experiment results show that, under 252 dB/20 μs ISP interference, the specific sonar receiver will produce sustained cut top oscillation above 30 ms, which may affect the receiver and block the regular sonar signal.展开更多
A 2＂×2＂BC501A liquid scintillation detector with a gain stabilization system is developed and applied to neutron andγ-ray measurement on the EAST tokamak.Energy calibration of a liquid scintillator using a fas...A 2＂×2＂BC501A liquid scintillation detector with a gain stabilization system is developed and applied to neutron andγ-ray measurement on the EAST tokamak.Energy calibration of a liquid scintillator using a fast coincidence method is presented and compared with the Monte Carlo simulation.Determination of the proton light output function of the BC501A is presented.Results from dedicated experiments with an Am-Be neutron source,γsource and quasi-monoenergetic neutron beams,and from measurements on EAST tokamak are presented and discussed.展开更多
An equivalent circuit model is built for a coupled-resonator pulse compressor. Based on the circuit, the general second order differential equation is derived and converted into the first order equation to save comput...An equivalent circuit model is built for a coupled-resonator pulse compressor. Based on the circuit, the general second order differential equation is derived and converted into the first order equation to save computing time. In order to analyze the transient response and optimize parameters for the pulse compressor, we have developed a simulation code. In addition, we have also designed a three-cavity pulse compressor to get the maximum energy multiplication factor. The size of the cavities and coupling apertures is determined by HFSS.展开更多
We demonstrate a simple method to obtain accurate optical waveforms with a gigahertz-level programmable modulation bandwidth and a watt-level output power for wideband optical control of free atoms and molecules.Arbit...We demonstrate a simple method to obtain accurate optical waveforms with a gigahertz-level programmable modulation bandwidth and a watt-level output power for wideband optical control of free atoms and molecules.Arbitrary amplitude and phase modulations are transferred from microwave to light with a low-power fiber electro-optical modulator.The sub-milliwatt optical sideband is co-amplified with the optical carrier in a power-balanced fashion through a tapered semiconductor amplifier(TSA).By automatically keeping TSA near saturation in a quasi-continuous manner,typical noise channels associated with pulsed high-gain amplifications are efficiently suppressed.As an example application,we demonstrate interleaved cooling and trapping of two rubidium isotopes with coherent nanosecond pulses.展开更多
基金supported by the National Natural Science Foundation of China (10974154)the National Innovation Project of China for Undergraduates (101069935)
文摘For anti-jamming and anti-countermeasure techniques of the sonar receiver, the response characteristics of the automatic gain control （AGC） circuit and the survivability of the prime circuit under strong interference are analyzed by simulations and experiments. An AGC simulation model based on the voltage control amplifier VCA810 prototype is proposed. Then static and dynamic simulations are realized with single frequency signal and linear frequency modulated （LFM） signal commonly used in the active sonar. Based on intense sound pulse （ISP） interference experiments, the real-time response characteristics of each module of the receiver are studied to verify the correctness of the model as well as the simulation results. Simulation and experiment results show that, under 252 dB/20 μs ISP interference, the specific sonar receiver will produce sustained cut top oscillation above 30 ms, which may affect the receiver and block the regular sonar signal.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2013GB106004 and 2012GB101003)National Natural Science Foundation of China(No.91226102)
文摘A 2＂×2＂BC501A liquid scintillation detector with a gain stabilization system is developed and applied to neutron andγ-ray measurement on the EAST tokamak.Energy calibration of a liquid scintillator using a fast coincidence method is presented and compared with the Monte Carlo simulation.Determination of the proton light output function of the BC501A is presented.Results from dedicated experiments with an Am-Be neutron source,γsource and quasi-monoenergetic neutron beams,and from measurements on EAST tokamak are presented and discussed.
文摘An equivalent circuit model is built for a coupled-resonator pulse compressor. Based on the circuit, the general second order differential equation is derived and converted into the first order equation to save computing time. In order to analyze the transient response and optimize parameters for the pulse compressor, we have developed a simulation code. In addition, we have also designed a three-cavity pulse compressor to get the maximum energy multiplication factor. The size of the cavities and coupling apertures is determined by HFSS.
基金supported by the National Key Research and Development Program of China(Nos.2016YFA0302000 and 2017YFA0304204)the National Natural Science Foundation of China(NSFC)(No.12074083)the National Key Scientific Instrument and Equipment Development Project(No.12027806)。
文摘We demonstrate a simple method to obtain accurate optical waveforms with a gigahertz-level programmable modulation bandwidth and a watt-level output power for wideband optical control of free atoms and molecules.Arbitrary amplitude and phase modulations are transferred from microwave to light with a low-power fiber electro-optical modulator.The sub-milliwatt optical sideband is co-amplified with the optical carrier in a power-balanced fashion through a tapered semiconductor amplifier(TSA).By automatically keeping TSA near saturation in a quasi-continuous manner,typical noise channels associated with pulsed high-gain amplifications are efficiently suppressed.As an example application,we demonstrate interleaved cooling and trapping of two rubidium isotopes with coherent nanosecond pulses.
