A 12-channel dual-lock-in platform for magneto-resistive DNA detection with ppm resolution

摘要

Although lock-in detection is a well consolidated sensing technique, state-of-the-art commercial lock-in amplifiers do not allow reaching ppm resolution on long time scales due to low-frequency noise. We present a custom, multichannel platform that provides 0.7 ppm resolution, dedicated to pathogen DNA detection by means of Magnetic Tunnel Junction magneto-resistive sensors. A double modulation architecture (magnetic and electrical) is implemented in the FPGA that represents the core of the embedded digital processing unit.