| 摘要 |
PURPOSE:To make the check of the number of revolutions of a disc quickly and accurately, by reading out a plurality of check signals of ROM based on the sector signal detecting the notch for the sector of the disc and detecting the shift in the sector signal. CONSTITUTION:Based on the sector signal (b) by the detection of notches 3... of a disc 1 in response to the revolution of the disc 1, the chopping circuit 16 chops the clock (a) and applies the set output (c) to the NAND gate 22. The reset output (d) delayed by one clock further from the output (c) is produced and two sets of check signals (e) and (d) are read out from the ROM18 to detect the shift in the time of production for leading and trailing edges of the signal (b) via the NAND gate 22 and the D type FF19. Further, when the number of revolutions of the disc 1 is changed more than a given value, the error signal is produced via the NAND gate 23 and the JK type FF, allowing to check the number of revolutions of the disc for memory of the electronic computer quickly and surely. |
