| 摘要 |
PURPOSE:To attain the recording/reproducing characteristics equivalent to an auxiliary magnetic pole exciting system with a main magnetic pole exciting system, by obtaining two-time differential waveforms of the output of a magneto-resistance effect type magnetic head when the information written to a vertical recording medium of a compound double-layer film recording medium and detecting the zero cross point of said differential waveforms. CONSTITUTION:The information is written to a compound double-layer film recording medium 6 by a unipolar type recording head 1 and then reproduced by a magneto-resistance effect (MR) type magnetic head 11. In this case, an isolated reproduction waveform similar to a function tan<-1> is obtained. Then a differential waveform (Fig. a) of said isolated waveform is obtained, and the effect of the DC component of said differential waveform is eliminated. This differential waveform is differentiated again to obtain a waveform (Fig. b), and the zero cross point of said waveform is detected. Therefore the zero cross point is detected for said isolated reproduction waveform. When the information is read out by the head 11, a sense current is supplied to the head 11. As a result, the resistance change of the head 11 due to the magnetic field of a vertical magnetic recording medium 3 is converted into a voltage change. This voltage is amplified by a preamplifier 13 and then differentiated two times by the 1st and 2nd differentiation circuits 14 and 15 to be supplied to a zero cross point detector 17 via an LPF16 for detection of the zero cross point. |
