共查询到18条相似文献,搜索用时 125 毫秒
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介绍了X波段极低噪声低温放大器的研制。在≤15K的环境温度下,X波段100MHz带宽内,实测放大器的等效噪声温度:≤8.8K;增益:>36dB;带内起伏:<0.4dB;输入反射损耗:<-22dB;输出反射损耗:<-20dB。它的研制成功,将可以替代进口产品满足X波段低温接收机的研制需要。 相似文献
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介绍了8~9GHz极低噪声低温放大器的研制。在≤15K的工作温度下,实测放大器的主要性能指标如下:等效噪声温度≤7.9K;增益>31dB,带内起伏≤1dB;输入反射损耗<-21dB;输出反射损耗<-23dB。它的研制成功,实现了深空探测、天文观测等X波段宽带低温接收机的核心器件国产化。 相似文献
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介绍了低温低噪声放大器使用的HEMT(高迁移率晶体管)器件噪声模型的建立,对HEMT用S参数和噪声参数讲行仿直,获取适合的模型.给出了实例,放大器在低温10K工作,增益≥30dB,噪声温度≤4K. 相似文献
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中介绍了S波段低温低噪声放大器的研制.在15K左右的环境温度下,300MHz带宽内,实测放大器的等效噪声温度≤4.6K,增益≥35dB,增益平坦度≤1.0clB,输入、输出回波损耗≤-20dB.它已经成功运用于射电天文等领域. 相似文献
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介绍了低温低噪声放大器的研制历史、现状及应用情况 ,举例分析了在该类放大器的结构设计中需要解决的关键技术 ,对军事和民用装备的有关领域有参考作用。 相似文献
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超导接收前端以超导滤波器和高电子迁移率晶体管(HEMT)低温放大器构成核心微波电路,其HEMT放大器在低温下拥有极低的工作噪声,但对偏置供电的要求很高,只有在特定偏置下,系统才拥有最佳的工作稳定度、高增益和低噪声。本文针对多信道超导接收前端,设计了一种多通道、模块化,带程控通讯的超导接收前端用HEMT低噪放电控组件,为设备核心射频通道提供供电、切换和远程控制。其供电偏置可调、供电纹波≤3 mV,并提供多路TTL电平接口,支持RS485数据通讯控制,便于模块化安装,在超导接收前端分机中工作状况良好。 相似文献
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Kazuro Kikuchi 《Fiber and Integrated Optics》1993,12(4):369-380
We show that the classical model of the amplifier noise can well describe the amplifier-noise characteristics and that the signalgain, the spontaneous emission factor, and the optical bandwidth are all the information necessary for analyzing the amplifier-noise characteristics. The accumulation of noise in the amplifier chain is also discussed in detail. 相似文献
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K. Hinton 《Optical and Quantum Electronics》1991,23(6):755-773
A model for the noise processes in a Fabry-Perot semiconductor laser amplifier is presented. This model is based on the application of perturbation techniques to the travelling-wave rate equations for the amplifier. The model includes the effects of end-facet reflections and the backwards-travelling wave into the amplifier. The noise power spectral densities for the intensity, electron density and phase noise are derived. The model can be applied to an arbitrary gain profile and does not require homogenization of the photon field over the length of the device. 相似文献
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Noise measurements on high-transimpedance amplifiers suitable for long-wavelength OTDRs give results higher than is predicted by normal noise models. Consequently, we have developed two useful techniques to measure independently the noise contribution of the JFET and the feedback resistor to the overall amplifier noise. p ]Our results show that the noise of the JFET is in accordance with an accurate theoretical model for such a device. In contrast, the noise from the feedback resistor is much higher than is predicted from the normal resistance-capacitance model for such a component. This increase results from the distributed nature of high-ohmic resistors. Our results indicate that both choice of resistor manufacturer and individual selection of a resistor from a specific manufacturer are warranted. By selecting a low-noise resistor we demonstrate a 500-M transimpedance amplifier with an input equivalent noise current of 13.8 pA. In comparison, the same amplifier with a noisy resistor had an input equivalent noise current of 23 pA. p ]We use our results to show that a reasonable value of the input equivalent noise current of a low-noise photodiode-amplifier combination is 20 pA. 相似文献
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We measure the phase fluctuation in a high-power fiber amplifier using a multi-dithering technique.Its fluctuation property is qualitatively analyzed by the power spectral density and integrated spectral density.Low frequency fluctuations caused by the environment are dominant in the phase fluctuations in an amplifier,whereas the high frequency components related to laser power affect the control bandwidth.The bandwidth requirement of the active phase-locking is calculated to be 300 Hz,670 Hz,1.6 kHz,and 3.9 kHz under the output power of 25,55,125,and 180 W,respectively.The approximately linear relationship between the control bandwidth and laser power needs to be further investigated. 相似文献
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Temperature-dependent gain and noise in fiber Raman amplifiers 总被引:2,自引:0,他引:2
An experimental investigation of the temperature dependence of the gain and noise performance of a silica-fiber Raman amplifier is described. A decrease in the Raman scattering cross section in a fiber amplifier cooled from a temperature of 300 K to 77 K was measured and found to be in agreement with theoretical values. No difference between the Raman gain coefficients at these two temperatures was observed. 相似文献