ADAPTIVE MEDIUM SPEED DRIVING UNIT, TIMING REFERENCE SERVO SYSTEM AND TRACKING CLOCK GENERATING METHOD

摘要

PROBLEM TO BE SOLVED: To form a tracking clock of high precision in formation of the tracking clock used for writing data on a magnetic medium so that data bits written on the magnetic medium are arranged on the magnetic medium at equal intervals independently of speed. SOLUTION: In an adaptive medium speed driving unit used for a magnetic storage medium, a timing reference servo pattern is written in the magnetic storage medium by forming a servo band. The servo pattern contains transition and a driving device reads the servo pattern. A driving device contains a servo reading element 39 which is constituted so as to generate a signal containing a recognizable signal event corresponding to the servo reading element 39 reading servo transition by reading the servo pattern. Further, the driving device contains a magnetic head 38 containing a data writing element 170 and a servo decoder 48 containing time capture logic 56 constituted so as to determine time quantity between signal events and a digital controlled oscillator in which the writing element 170 can be utilized for writing data in the storage medium at equal intervals independent of speed of the storage medium and which contains a polyphase clock generator and thereby enhances resolution.