论文部分内容阅读
本文介绍一台低噪声FET放大器的设计及特性,它用于de-SQUID信号检测,同时分析了放大器输入端信号传输线对输入噪声电流的影响。在SQUID调制频率50kHz条件下,利用双绞漆包线作为输入信号线的放大器噪声电压为0.48nV/Hz~(1/2),噪声电流为79.2fA/Hz~(1/2).放大器增益66dB,3dB带宽为15kHz～150kHz.该放大器已用于PIC-1型dc-SQUID超导磁强计中,频率1Hz时的磁通噪声(rms值)为1×10~(-4)φ_(orms)Hz~(1/2).
This article describes the design and features of a low-noise FET amplifier that is used for de-SQUID signal detection and analyzes the effects of the signal transmission line at the input of the amplifier on the input noise current. The amplifier noise voltage is 0.48nV / Hz ~ (1/2) and the noise current is 79.2fA / Hz ~ (1/2) when the SQUID modulation frequency is 50kHz. The amplifier gain is 66dB, 3dB bandwidth of 15kHz ~ 150kHz. The amplifier has been used in PIC-1 dc-SQUID superconducting magnetometer at a frequency of 1Hz flux noise (rms value) of 1 × 10-4 (φ) (orms) Hz ~ (1/2).