Patent ID: 6774626
Filing Date: 2004-08-10
Classification: G11B

Abstract:
A device for measuring a magnetic property of a magnetic reproducing head at a measurement point thereon, comprising:means for applying a first magnetic field which oscillates at a predetermined oscillation frequency to the measurement point; means for applying a second magnetic field of which strength changes slower compared with the oscillation frequency of the first magnetic field to the measurement point; means for detecting a signal generated by the magnetic reproducing head according to the total strength of the first magnetic field and the second magnetic field; and means for measuring the signal's dependency on applied magnetic field strength, wherein the measuring means comprises means for extracting amplitude components synchronizing with the oscillation frequency from the signal; and means for calculating changes of the signal against the total magnetic field strength based on the extracted amplitude components; and wherein the extracting means extracts amplitude components synchronizing with double the oscillation frequency from the signal.