| 摘要 |
PURPOSE:To prevent a data part of other sector and a corresponding data part of the sector from being misconceived, by providing a counting means such as a timer, and obtaining a time-out error unless the data part is detected within a specified time after detecting an address part. CONSTITUTION:Unless an address marker 8 of a data part 5 is detected by an address marker detecting circuit 21, an address marker detecting signal 28 does not become true even if an address detecting signal 24 is applied to an AND gate 26, therefore, an AND condition of the AND gate is not formed, and no signal is applied to a data part analyzing circuit 29 from the AND gate 26. Accordingly, the data part analyzing circuit 29 is not started. On the other hand, a timing circuit 25 starts its time counting operation by an address detecting signal 24, and in the end, it reaches a fixed time, namely, a set time limit. Subsequently, a time-out error signal 33 is outputted from the timing circuit 25, and resets an object address detecting circuit 23 through an OR gate 32. |
