Wideband front end for high-frequency SQUID electronics

摘要: We report the development of a wide-bandwidth, low-noise front end to facilitate high frequency operation both LTS and HTS DC SQUIDs. A transformer novel design non-resonantly matches dynamic impedance SQUID through twisted pair room-temperature amplifier. The amplifier uses active feedback techniques flatten response signal path. When operated in conjunction with electronics (developed by IBM T.J. Watson Labs) modulation 16 MHz, Quantum Design SQUID, system achieved slew rate 1.9/spl times/10/sup 6/ /spl Phi//sub 0/ s/sup -1/, closed-loop performance 5 MHz noise level 5.5 mu//spl 0//(Hz)/sup 1/2/. from input output was relatively flat 2 25 usable 45 MHz. believe is limited cabling expect significant improvements miniaturized design.