Patent ID: 6052244
Filing Date: 2000-04-18
Classification: G11B

Abstract:
A servo signal processing apparatus for processing a servo signal corresponding to servo information from a servo area provided on a recorded medium for controlling a read head, the servo area including a servo mark area for storing a servo mark indicative of a beginning of the servo area, a gray mark area for storing a gray mark indicative of a beginning of information for position control for the read head, and a gray code area for storing information, the apparatus comprising:an A-D converter for sampling and converting the servo signal to a digital data signal;a digital filter connected to the A-D converter for filtering the digital data signal based on a sampling clock, and for outputting filtered digital data;a servo mark detector connected to the digital filter for receiving the filtered digital data and for detecting the servo mark area based on a first continuity of a predetermined logical value; anda gray code decoder connected to the digital filter for receiving the filtered digital data and for detecting the gray mark area based on a second continuity of a predetermined logical value, wherein the gray code decoder decodes the information stored in the gray code area following the detected gray mark area, wherein the servo mark detector includes a 0 burst counter for counting the first continuity of a predetermined logical value;the servo mark detector increments the 0 burst counter when data received from the digital filter is 1, and clears the 0 burst counter when the received digital data is 0; andthe servo mark detector determines the continuity of the logical value of the data based on the value of the 0 burst counter in order to detect the servo mark area.