| 摘要 |
PURPOSE:To improve the reliability with reduction of the current which is supplied to a coil for impression of driving magnetic field by reducing the bubble driving magnetic field or the bias magnetic field less than the value of a normal means after writing the magnetic bubble to a memory elements and detecting a minor loop having a lower level of bubble transfer power. CONSTITUTION:A normal memory test current A1 is flowed to coils 3 and 4 to generate a driving magnetic field, and a transfer gate 17 is actuated in a state where a normal bias magnetic field is applied by a permanent magnet 5. Thus the magnetic bubbles written within a major loop 11 are stored in each minor loop 12. The current A1 is turned off, and a current A2 which has an extremely small level yet can drive bubbles is flowed to transfer the stored bubbles in >=1 round within the loop 12. Then the current A2 is turned off, and the current A1 is flowed to actuate the gate 17. Thus the bubble drawn out to the loop 11 is read and written by a detector 13 and compared with the bubble. In such a way, the stay and delay of transferred bubbles are detected to detect a defective transfer loop. |
