适应于特殊信号的低噪声前置放大器

本文着重讨论了在超高频,超低频、高源和低源阻抗等特殊情况下,低噪声前置放大器的实用设计原则和利用E_a～R_s和E_n～f曲线来选择使用低噪声运放的正确方法,并给出了设计实例。文章还结合屏蔽、接地,相干检测等微弱信号检测理论,讨论了隔离放大器的内部结构和外部接线的原理,确立了外围元件的选择并给出了有关的计算公式。

A SUITABLE FOR SPECIAL SIGNALS PRE-AMPLIFIER OF LOW-NOISE

In this paper, the author had an especial discnssion on thedesigning principles of the pre-amplifier of low-noise under the special opera-tion conditions, such as ultra high frequency, ultra low freguency, low sourceimpedance, high source impedance, etc. The author also explained the currentmethod to choose an operational amplifier by using the E_n-R_? and E_n-f cur-ves. And a practical designing example Was also given. When using the sheldinggrounding and correlative detection of the weak signal detection theories, it dis-cured the principles of the internal construction and external circuits of theislation amplifier, and established their choosing. Principles of the peripheralparts and their relative culculating formulas were given.