Abstract: Apparatus and method for reducing nonlinearities in a position error signal (PES) of a disc drive data handling system. The disc drive data handling system includes a disc recording surface having a number of tracks and a controllably positionable read/write head. A servo circuit generates a sequence of PES samples indicative of head position with respect to a selected track using servo position data samples transduced from the selected track and a first set of compensation values selected to reduce nonlinearities in said PES samples. The PES samples are combined with the first set of compensation values to generate an updated set of compensation values. This process is preferably repeated a number of iterations to converge to a final set of compensation values which provide a substantially linear PES across the radial width of each track.

Abstract: Apparatus and method for reducing nonlinearities in a position error signal (PES) of a disc drive data handling system. The disc drive data handling system includes a disc recording surface having a number of tracks and a controllably positionable read/write head. A servo circuit generates a sequence of PES samples indicative of head position with respect to a selected track using servo position data samples transduced from the selected track and a first set of compensation values selected to reduce nonlinearities in said PES samples. The PES samples are combined with the first set of compensation values to generate an updated set of compensation values. This process is preferably repeated a number of iterations to converge to a final set of compensation values which provide a substantially linear PES across the radial width of each track.

Abstract: A device is provided for testing the strength of plant stalks. The device includes a frame adapted to be secured to a tractor or combine. An upright member is pivotally attached to the frame and has an arm extending substantially horizontally therefrom. A spring is connected between the upright member and the frame so as to provide biasing against the pivotal movement of the upright member and attached arm. In operation, as the tractor or combine moves along a row of plants, the arm engages each plant which bends over and breaks if the stalk is not sufficiently strong to resist the force of the forwardly moving arm. If the stalk is sufficiently strong, the stalk will bend but not break or the arm will pivot rearwardly until it passes by the stalk and then is automatically returned to its initial position.