Defect Accommodation in Track Positioning Servos
Original Publication Date: 1981-Jun-01
Included in the Prior Art Database: 2005-Feb-11
Track-positioning servos for flexible record media have to accommodate defects occurring in the servo signals A and B. That is, the integral of servo signal A should equal the integral of servo signal B when the head is faithfully tracking a data track. According to the present article, defects can be accommodated for faithful track following by using a plurality of peak detectors PD and a pair of counters for repetitively peak amplitude sensing the position (POS) portion of the servo signals A and B and selecting the maximum amplitude from A or B for input to a servo combiner to generate a position error signal (PES). In one constructed embodiment, each of the servo signals A and B has a preamble and postamble separated from the positioning signals POS by a start and stop flag, respectively.