Signal detection technology for giant magnetoresistance sensors

摘要

Presently, many attentions have been paid on low-noise pre-amplifier circuits and steady signal processing methods, but seldom on the combination of two technologies. In this paper, a small size low noise pre-amplifier circuit with 110 dB Common Mode Rejection Ratio (CMRR) has been developed for giant magnetoresistance sensors (GMR) and its equivalent input noise voltage density is about 3.7 nV/(Hz)~(1/2)@3.5 KHz. In addition, we proposed a new signal processing method for the sensors. In the method, we defined the quotient between the complex multiplex computation times and the output data num as a new figure of merit to evaluate that algorithm efficiency in signal detection, and name that quotient the computation times-to-output data num ratio (CTOR). Simulation results showed that the new method realized better parameters evaluation precision and higher efficiency than Modified Rife method, could be implemented easily in embedded systems.