| 摘要 |
PURPOSE:To discriminate a recording system of a recording medium by making use of the data since just after the detection of an index until just before the top gap in the preamble part of a data format where the 1st sector begins. CONSTITUTION:The data of the top gap in a preamble part in the format of a floppy disc is FF in the case of FM recording and is 4E in the case of MFM recording and is written with several bytes continuously; therefore, the number of pulses withot jitter of the read signal 1 when the pulse width of three is made 32mus is eight in the case of FM recording and is six in the case of MFM recording. Thereupon, if the value N to be preset from a data input part 5 where the number of pulses in FM recording at the output pulse width (t) of M1 is designated as (m) and the number of pulses in MFM recording as (n) is set at m+n/2 by making use of the difference between the same, the discrimination of whether the FM recording of MFM recording is accomplished from the borrow output of six including the fluctuating margin of the number of pulses owing to some jitter or the like. |
