【摘要】 目前,国内生产的直流数字电压表,其最高灵敏度为0.1μV,距世界先进水平相差两个量级,为了把该项指标再提一个量级,我们研制了十毫微伏放大器。文中介绍了该放大器的原理,对MOS—FET斩波器进行了详细的分析。并从噪声理论出发,讨论了信号源阻抗,前级有源器件及工作点的选取;且引入“快速电路”较好地解决了通频带和灵敏度的矛盾,最后阐明了低噪电路的工艺要求。更多还原

【Abstract】 The Max.sensitivity of D.C. digital Voltmeter reached present in our countvy is 0.1μV. In compares with the advance level of world, it is about two orders of megnitude lagging. In order to raise the sensitivity by one order of magnitude. We have devoloped the 10nv amplifier. This paper introduces. the principle of the 10nv amplifier, The MOS—FET chopper is analysed in detail. According to the noise theory, the determinations of source risestance and active component of first stage, and selection of operating point are discussed. The "fast speed circuit" are applied for compromising the contradiction between Sensitivity and band pass. Finally, We deal with to technique requirements of the low noise circuit.更多还原