System and method for processing analyte signals in GMR-based detection of biomarkers

A signal processing system used for GMR-based detection of a target analyte in a sample under test, comprising: a measurement circuit configuration unit configured to build a GMR sensor measurement circuit by routing in at least one GM Rsensor, and to build a reference resistor measurement circuit by routing in at least one reference resistor; a magnetic field excitation unit configured to apply an AC magnetic field of frequency o2 to the at least one GMR sensor; a carrier signal applying unit configured to apply acarrier signal of frequency oi to the GM Rsensor measurement circuit, and apply carrier signals of frequency i, 01+02, and oi 02 to the reference resistor measurement circuit; a measurement signal pick-up unit coupled to the measurement circuits, configured to collect reference resistor measurement signals from the reference resistor measurement circuit and GMR sensor measurement signals from the GMR sensor measurement circuit; and a phase sensitive solution unit coupled to the measurement signal pick-up unit, configured to analytically solve for resistance change of the at least one GM Sensor based on both the reference resistor measurement signals from the reference resistor measurement circuit and the GM Rsensor measurement signals from the GM Rsensor measurement circuit.