The invention discloses a
system and a method for reducing
noise of a
tunnel magnetoresistance sensor. The
system comprises a coil-free shielding cylinder and a
driving circuit, wherein the coil-freeshielding cylinder is made of a soft magnetic material with high magnetic
conductivity; a to-be-processed TMR sensor is placed in the center of the coil-free shielding cylinder; the output end of theTMR sensor is connected with the input end of the
driving circuit; the coil-free shielding cylinder is based on the
supersaturation characteristic of a high-permeability soft magnetic material, and when
alternating current is introduced, the shielding capability of the coil-free shielding cylinder changes at
high frequency, so that a to-be-measured direct-current
magnetic field of the TMR sensor is converted into a high-frequency alternating-current
magnetic field, and 1 / f
noise of the TMR sensor is reduced; the
driving circuit performs phase-sensitive detection and low-pass filtering on an output
signal of the TMR sensor based on the reference
signal, filters out a sum frequency
signal, retains a difference frequency signal, and further filters out 1 / f
noise of the TMR sensor. According to the coil-free shielding cylinder, multiple turns of coils do not need to be wound, new noise cannot be introduced, and the
noise reduction effect is good.