| 摘要 |
PURPOSE:To increase a reading margin, to reduce an error rate and to use the titled device for a long period by changing the writing density and writing format of a track which is ordinally abandoned as a defective one. CONSTITUTION:When the error rate of a specific track in a floppy disc is increased, an FF19 is reset and an FF22 is set up in a latch circuit 5 to switch an 8-inch double density system clock signal to a 5-inch FM system clock signal and also switch a VFO circuit 11 (for 8-inch FMF) to a VFO circuit 14 (for 5- inch FM). Consequently the bit shifting margin is increased from + or -0.5sec to + or -2sec, i.e. 4 times, making it possible for instance, to remove an error generated by bit shifting due to the reduction of an output level. |
