MAGNETO-RESISTANCE EFFECT TYPE MAGNETIC HEAD DEVICE

摘要

PURPOSE:To remove a secondary higher harmonic wave and reduce distortion by alternating the in-phase and opposite-phase output voltages of a magneto-resistance effect sensitive MR part which is applied with the superposed magnetic field of a rectangular wave bias magnetic field and a signal magnetic field in synchronism with the bias magnetic field. CONSTITUTION:A rectangular wave signal from a generator 20 is supplied to a buffer 21 to flow a bias current IB to a bias conductor 3 with the output of the buffer. The MR sensitive part 5 is supplied with a signal magnetic field Hs while the rectangular wave magnetic field established around a conductor 3 with the current IB and a bias magnetic field based upon a magnetic field produced with the detection current iMR of the MR sensitive part 5. The terminal voltage across the MR sensitive part 5 based upon resistance variation with the magnetic field Hs is led out by a means 2 and supplied to an amplifier 14 through a capacitor 16. Then, the output of the amplifier 14 and its phase-inverted output are alternated through a switch 25 controlled with the rectangular wave signal and supplied to an LPF26, thereby obtaining a signal output corresponding to the magnetic field Hs at an output terminal 15.