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31.
在会堂扩声时,由于接收声音信号的传声器与重放这些信号的扬声器处于同一空间,因此,不可避免地存在着声反馈,甚至产生啸叫的现象。这是会堂扩声中最感头痛和最难克服的一个问题。我们根据会堂的声学环境,在不损伤音质的前提下,适当利用扩声系统的多频音调器,并注意传声器和扬声器的指向性,对解决这一问题收到了一定的效果。 相似文献
32.
26W near diffraction limited Q-switched green laser based on a diode-end-pumped master oscillator power amplifier 下载免费PDF全文
An efficient acousto-optically Q-switched extracavity frequency-doubled 532nm laser based on a diode-end-pumped master oscillator power amplifier (MOPA) is demonstrated. With a type I non-critically phase-matched LBO, 26W of average power at 532nm in a near diffraction limited mode at a repetition rate of 30kHz was generated under 43W pump power of 1064nm Nd:YVO_{4} laser, which correspond to a frequency-doubling conversion efficiency of 60%. 相似文献
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信号的功率放大器是电子通信系统的关键器件之一,功放的输出信号相对于输入信号可能产生非线性变形,这将带来无益的干扰信号,研究其机理并采取措施改善,具有重要意义.通过利用无记忆非线性功放和记忆非线性功放的实测数据用数学方法对其分别进行建模,而后使用前置预失真器的方法改善功放的非线性特性,并对其中预失真器的建模做了研究,采用间接学习型结构构建预失真器模型.仿真结果显示功放非线性模型结合预失真器模型能够很好地逼近实际情况,并且能很好地抑制带外频谱扩展. 相似文献
35.
We demonstrate a 30-W all-fiberized laser in a master oscillator power amplifier(MOPA) structure with a central wavelength of 1 950 nm.The laser is a continuous-wave(CW) operation with double-clad Tm-doped silica fiber pumped by pigtailed laser diodes with a central wavelength of 793 nm.The optical-to-optical efficiency of the MOPA system is 37.5% with respect to the total 80-W pump power.The maximal slope efficiency of the system is approximately 43%,which belongs to the main amplifier and exceeds the Stoke limit.No obvious amplified spontaneous emitting(ASE) is observed in the experiment,and the power can be scaled straightforwardly by improving the pump power. 相似文献
36.
Amplified spontaneous emission (ASE) always occurs in high-power DF laser systems with master oscillator-power amplifier (MOPA) configuration. ASE not only reduces the energy extraction efficiency of the laser system, but also negatively influences its heat management. The interaction between the ASE flux and the coherent laser flux, as well as the effect of ASE on cuboid DF amplifiers, is studied using a finite difference method and an iterative arithmetic. In addition, the influence of ASE on coherent laser amplification is discussed in detail. 相似文献
37.
介绍了用工业控制计算机控制卫星地面站功率放大器的一种方法,阐述了控制系统的硬件和软件基本组成。 相似文献
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A single-frequency pulsed erbium-doped fiber(EDF) laser with master-oscillator power-amplifier configuration at 1 533 nm is developed. A short-cavity,erbium-doped phosphate glass fiber laser is utilized as a seeder laser with a linewidth of 5 kHz and power of 40 mW. The seeder laser is modulated to be a pulse laser with a repetition rate of 10 kHz and pulse duration of 500 ns. The amplifier consists of two pre-amplifiers and one main amplifier. The detailed characteristics of the spectrum and linewidth of the amplifiers are presented. A pulse energy of 116 μJ and a linewidth of 1.1 MHz are obtained. This laser can be a candidate transmitter for an all-fiber Doppler wind lidar in the boundary layer. 相似文献
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A high repetition rate Tm:Ho:LuLiF master-oscillator and polarization-maintaining (PM) Tm-doped fiber power-amplifier system is presented.A 11.3-kHz,0.4-nm line width,0.89-W Tm:Ho:LuLiF seed laser is developed.Using a two-stage PM Tm-doped fiber power amplifier system,32.4-W output power is obtained with 0.4-nm line width at a central wavelength of 2058.5 nm,corresponding to 0.66-W seed laser.The laser spectrum and pulse profile are measured. 相似文献