Patent ID: 6043647
Filing Date: 2000-03-28
Classification: G01R,G01V

Abstract:
An apparatus for detecting anomalies in a magnetic field, comprising:means for generating a square wave;a sensor driven by said square wave generator for sensing changes in the magnetic field of said sensor, said sensor outputting a first pulse train having an equilibrium value in the absence of anomalies in the magnetic field and a pulse height which changes in response to anomalies in the magnetic field;a sensor amplifier connected to the sensor for receiving the first pulse train from said sensor and for amplifying changes in the first pulse train, said sensor amplifier outputting a feedback signal to said sensor; said feedback signal representing the difference between the equilibrium value and the changes in the pulse height due to the anomaly in the magnetic field; said sensor amplifier correcting the first pulse train to the equilibrium value;a main amplifier connected to the sensor amplifier for amplifying a filtered waveform output of the sensor amplifier; anda display responsive to the main amplifier.