A magnetic field sensor for measuring movement of a target object, the movement in an x-z plane within x-y-z Cartesian coordinates with x, y, and z orthogonal axes, the target object capable of rotating about an axis of rotation parallel to the y-axis, the magnetic field sensor comprising: a substrate having a major planar surface; and an electronic circuit disposed upon the substrate, the electronic circuit comprising: a plurality of magnetic field sensing elements disposed upon the major planar surface of the substrate, the plurality of magnetic field sensing elements including two magnetic field sensing elements (502, 508) disposed upon the major planar surface of the substrate, the two magnetic field sensing elements (502, 508) having respective major response axes parallel to the major planar surface of the substrate, the two magnetic field sensing elements (502, 508) having the respective major response axes parallel to each other, a line passing through any two of the plurality of magnetic field sensing elements not intersecting the target object, wherein the two magnetic field sensing elements (502, 508) are configured to generate a respective two magnetic field signals (510, 512); and a differential amplifier coupled to receive the two magnetic field signals (502, 508) and configured to generate an output signal as a difference of the two magnetic field signals (510, 512), the output signal indicative of a position of the target object relative to the two magnetic field sensing elements (502, 508), wherein the major surface of the substrate overlaps the target object such that a line perpendicular to the major surface of the substrate, within twenty degrees of parallel to the axis of rotation of the target object and passing through at least one of the two magnetic field sensing elements (502, 508), intersects the target object, and a line parallel to the major planar surface of the substrate is in a direction perpendicular to the axis of rotation of the target object. a substrate having a major planar surface; and an electronic circuit disposed upon the substrate, the electronic circuit comprising: a plurality of magnetic field sensing elements disposed upon the major planar surface of the substrate, the plurality of magnetic field sensing elements including two magnetic field sensing elements (502, 508) disposed upon the major planar surface of the substrate, the two magnetic field sensing elements (502, 508) having respective major response axes parallel to the major planar surface of the substrate, the two magnetic field sensing elements (502, 508) having the respective major response axes parallel to each other, a line passing through any two of the plurality of magnetic field sensing elements not intersecting the target object, wherein the two magnetic field sensing elements (502, 508) are configured to generate a respective two magnetic field signals (510, 512); and a differential amplifier coupled to receive the two magnetic field signals (502, 508) and configured to generate an output signal as a difference of the two magnetic field signals (510, 512), the output signal indicative of a position of the target object relative to the two magnetic field sensing elements (502, 508), wherein the major surface of the substrate overlaps the target object such that a line perpendicular to the major surface of the substrate, within twenty degrees of parallel to the axis of rotation of the target object and passing through at least one of the two magnetic field sensing elements (502, 508), intersects the target object, and a line parallel to the major planar surface of the substrate is in a direction perpendicular to the axis of rotation of the target object. a plurality of magnetic field sensing elements disposed upon the major planar surface of the substrate, the plurality of magnetic field sensing elements including two magnetic field sensing elements (502, 508) disposed upon the major planar surface of the substrate, the two magnetic field sensing elements (502, 508) having respective major response axes parallel to the major planar surface of the substrate, the two magnetic field sensing elements (502, 508) having the respective major response axes parallel to each other, a line passing through any two of the plurality of magnetic field sensing elements not intersecting the target object, wherein the two magnetic field sensing elements (502, 508) are configured to generate a respective two magnetic field signals (510, 512); and a differential amplifier coupled to receive the two magnetic field signals (502, 508) and configured to generate an output signal as a difference of the two magnetic field signals (510, 512), the output signal indicative of a position of the target object relative to the two magnetic field sensing elements (502, 508), wherein the major surface of the substrate overlaps the target object such that a line perpendicular to the major surface of the substrate, within twenty degrees of parallel to the axis of rotation of the target object and passing through at least one of the two magnetic field sensing elements (502, 508), intersects the target object, and a line parallel to the major planar surface of the substrate is in a direction perpendicular to the axis of rotation of the target object.