共查询到19条相似文献,搜索用时 109 毫秒
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本文以双端口网络的等效噪声模型为依托,通过采用精密测量所得的全参数En-In模型描述有源器件的噪声,以有效地提高低噪声放大器的设计精度;并通过研究En-In模型与其它六种等效噪声模型的谱关系实现噪声网络的模块化分析与设计,从而简化了噪声估算的过程。 相似文献
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本文通过描述同相放大器等效输入噪声电压谱密度Eni^2,导出了一种双极型运放En-In噪声矩阵参数的提取方法。并通过分析复相关系数的相对误差确定了提取准则。与现有方法相比,本文方法不仅可以完整的描述运放的噪声特性,而且还有利于不同运放电路(如宽带前置放大器,有源滤波器)的精确低噪声设计。最后,还充分验证了本文方法的可行性和正确性。 相似文献
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级联电路的En-In噪声性能分析 总被引:1,自引:1,他引:1
本文从级联电路的En-In噪声模型出发,分析了Friis定量的局生,并描述了级联电路En-In噪声的数学模型,模型形式简捷,参数提取方便,便于移植到电路噪声仿真程序中,文中不报前置级联电路的最小噪声条件,由于充分考虑了En与In噪 提的相关性,从而有效地保证了级联电路噪声计算的精度。 相似文献
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研究了如何从电路结构上减少运算放大器的噪声,以一种低噪声运放为例。着重介绍输入级设计。并借助计算机分析选择合适的输入器件尺寸。最后通过对运放噪声的仿真验证,得到了满意的结果。 相似文献
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基于红外探测器的前置放大器噪声特性分析 总被引:1,自引:0,他引:1
红外探测器的快速发展引起了国内外的广泛关注,但其读出电路的发展却相对滞后。如何降低电路噪声是读出电路研究热点之一,本文就红外探测器的电压型和跨导型两种基本结构前置放大器,建立了噪声等价模型,分析比较了其信噪比。并根据具体探测器对前置放大器进行了优化设计,以广泛适用于各种类型的红外探测器。 相似文献
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描述了有关放大器的噪声机理和特性,详细论述了前置放大器的低噪声设计步骤和过程,并根据晶体管的噪声特性曲线和噪声系数等值曲线对输入晶体管的偏置进行了理论计算。 相似文献
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采用0.18μm CMOS工艺,针对DMB-T/H标准数字电视调谐器应用,设计了一个基于噪声抵消技术的宽带低噪声放大器.详细分析了噪声抵消技术的原理,给出了宽带低噪声放大器的设计过程.仿真结果表明,在48~862 MHz频率范围内输入输出反射系数均小于-20 dB,噪声系数低于3 dB,增益大于17 dB,1 dB压缩点为-6dBm.在1.8V电压下,电路功耗为10.8mW. 相似文献
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In this paper, a novel method for analyzing the noise characteristic of solar cells with En-In model was studied. The En-In noise model in two-port network was introduced to study the low-frequency noise characteristic of solar cells. According to the relationship between the output noise power spectrum and the two noise parameters in En-In noise model of the solar cell, known as En and In, an accurate method for extracting the two noise parame- ters was proposed. At the same time, the measurement method for the both parameters from 1Hz to 10kHz was studied. After 1/f noise curve fitting and characteristic frequency of G-R noise extraction on the noise spectrums of a large amount of solar ceils, the analyzing results of spectrum compositions proved the validity and significance of the En-In noise model for noise analysis of solar cells. It also provided the essential theoretical and experimental basis for the further research on noise characteristic and reliability estimation of solar cells and PV modules. 相似文献
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《Microwave Theory and Techniques》1973,21(5):327-333
A thorough investigation is made on the frequency-dependent properties of a varactor diode loss resistance at UHF. The variation of the losses with frequency in a varactor diode mounted cavity has been theoretically investigated, and it is shown that the previously reported inverse-squared frequency dependence of the varactor loss resistance can be attributed to the distributed cavity losses transformed across the varactor diode. A new measurement technique is introduced in which the circuit losses are first matched to the input line instead of the varactor loss resistance as an application of the relative impedance method. Measurements carried out with this technique for five different varactor diodes showed that the loss resistances of these diodes are not frequency dependent. It is also shown that the choice of the varactor diode capacitance plays an important role on the parametric amplifier noise temperature at UHF. In an experimental parametric amplifier the effect of varactor diode capacitance on the noise temperature has been demonstrated. It has been theoretically and experimentally shown that, generally, varactor diodes having higher capacitances result in better noise temperature at UHF. 相似文献
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STFT, WT, WVD和Cohen类是目前信号分析和处理的有力工具。本文用WT的二次型时频形式分析了线性时频特性,研究了尺度图和变化窗谱图与Cohen类之间的关系;将尺度图纳入到Cohen类的框架,从而使WT广义化为时频域、时延频偏域的双线性时频分布以及谱相关域的二维频率分布;定义了尺度图、小波模糊函数(WAF)和小波谱相关函数(WSCF);分析了它们的物理意义。推导并仿真了单频、双频和高斯白噪声的WSCF,分析了各自的特性。最后通过引入一种离散小波变换的加密算法,解决了小波时频分布的计算问题。 相似文献