| 摘要 |
A digital data separator for use with apparatus for recovering binary information recorded in FM or MFM on magnetic media comprises a measuring unit which in correspondence with a read pulse n, supplies information representative of the actual duration of interval N between pulse n and the previous read pulse n-1. A media speed error recovery unit corrects such duration relative to the nominal speed according to a code representative of the media speed error, a peak-shift recovery unit which depending on the peak-shift of pulse n-1, determined on the basis of the temporal history of the most recent pulses n-3, n-2 and n-1 of such corrected duration, supplies duration information related to such interval and information representative of the direction and the entity of the peak-shift of the read out pulse n, and a speed error measuring unit defines a code representative of such error as the difference between the actual duration of a period consisting of a suitable number of subsequent intervals between read pulses and their nominal duration. This duration is corrected relative to the peak-shift of the pulses defining the beginning and the end of the period and is further "normalized" according to the nominal duration of the period. The speed error code is applied to the speed error recovery unit. The nominal duration of interval N is applied to a logic unit which generates a "window" signal and reconstructs the read pulse in a suitable phase relationship with the window signal.
|
