A disk drive has a sampled servo system controller and a disk. The disk has a
plurality
a plurality servo burst fields, each including a first normal burst field, a first
quadrature burst field, a second normal burst fields and a second quadrature burst
field. A portion of the first quadrature burst field is circumferentially contiguous
with the first normal burst field and spans a portion of a radial extent of the
first normal burst field. The second normal burst field is radially aligned with
and away from the first normal burst field and spans a portion of a radial extent
of the first quadrature burst field. The second quadrature burst field is radially
aligned with and away from the first quadrature burst field and spans a portion
of a radial extent of the second normal burst field. The first normal burst field
and the first quadrature burst field have a same first phase, the second normal
burst field and the first quadrature burst field have a same second phase and the
difference between the first phase and the second phase is less than 180 degrees.