A NONLINEARITY SPECIFICATION FOR CONSTRUCTING THE SERVO POSITION ERROR SIGNAL

A high performance disk file actuator servo requires a position transd ucer whose response is linear with displacement, Two concerns that det rimentally affect positional linearity are the nonlinear response of t he burst detector to burst amplitude and the nonuniform sensitivity of the magnetic read element across its pole faces. Nonuniform field sen sitivity is of particular concern with the advent of magneto resistive heads for embedded servo systems, and this paper gives specification for both for good actuator positioning.