| 摘要 |
PURPOSE:To improve the S/N ratio of bubble output, by arranging a bubble detector for data unit in the rotation direction of a rotating magnetic field at a prescribed angle to a bubble detector for defect information unit. CONSTITUTION:A bubble detector 26 for data unit is arranged in the rotation direction of the rotating magnetic field at a rotation angle of 0-180 deg., for example, 90 deg. to a bubble detector 21 for defect information unit, and signals are detected from detectors 21 and 26 with a phase difference of 90 deg., and the digital detection signal from a comparator 303 is inverted by an inverter 307. A data enable signal 409 and an information signal 408 based on defect information are outputted from sampling circuits 304 and 305 corresponding to detectors 21 and 26 respectively. When bubble presence and absence or the like are allowed to correspond to indefectible loops and defective loops as defect information respectively, the signal is not smaller in case of indefectible loops, and there are no influence because of the ignored signal in case of defective loops even if the signal of a data unit is smaller; and the just preceding detection output has no influence by a phase difference of 270 deg., thus improving the S/N ratio of the bubble detection output. |
