Patent ID: 7167329

Claim:
A machine comprising: a sensor or transducer; a compound phase pattern for use on a reference surface of said machine to compute the cross-track position relative to said pattern, said pattern described in logical coordinates in the time or down-track direction and in the orthogonal or cross-track direction, said pattern comprising a plurality of full servo blocks, and said full servo blocks comprising: a. basic elements in the form of slender parallelograms with detectable transitions at the long edges of said parallelograms, and b. certain of said basic elements called timing elements with said detectable transitions along isochrones or lines of equal values of said time coordinate, and c. one or more special groups of said timing elements to distinguish certain of said servo blocks or to identify a particular location as a timing reference within said servo blocks, and d. a plurality of phase bursts or groups of said basic elements at predetermined angles relative to said isochrones and with various predetermined pitches in said cross-track direction and with the same period λ in said down-track direction and spanning predetermined numbers of cycles in said down-track direction, with combinations of phases of said phase bursts encoded to define a unique cross-track position, whereby both fine and coarse components of said cross-track position are computed from phase information of data obtained from said transducer scanning said compound phase pattern only once in said down-track direction, and whereby the small variation of widths of said basic elements mitigates magnetic transfer of said pattern to said reference surface of a magnetic recording device, and whereby said compound phase pattern can be used as the final servo pattern for said magnetic recording device.