Filter unit is a key circuit of echo signal processing of magnetostrictive displacement sensor

which related to accurate acquisition of displacement detecting and subsequent digital processing.Through detection of echo signal generated by pure Ni waveguide wire and analysis on frequency characteristics

comparison study is carried out

echo signal filtering performance of two order Butterworth low pass filter

a four order band pass filter based on MAX275 is designed.Result shows that reasonable filter design can not only effectively restrain noise and interference signal

improving the signal to noise ratio of 10.2dB

but also can reduce the effect of remanent magnetization phenomenon and other interfering factors on useful signals.