Method and apparatus for detecting the direction of crankshaft rotation during a single tooth/slot transition

An apparatus for detecting direction of rotation of a toothed target wheel, comprising:

• a single differential sensor comprising a first magnetostatic element and a second magnetostatic element, said first and second magnetostatic elements being mutually spaced a predetermined distance apart;
• means for magnetically biasing said single differential sensor;
• a target wheel having a plurality of tooth edges providing a predetermined pitch, said target wheel being rotatively disposed in relation to said single differential sensor, said first and second magnetostatic elements being spaced circumferentially with respect to said target wheel;
• current source means connected with said single differential sensor for providing first and second voltages respectively from each of said first and second magnetostatic elements responsive to each tooth edge of said plurality of tooth edges passing said single differential sensor;
• and
• signal conditioning circuit means connected with said single differential sensor for providing a voltage output responsive to said first and second voltages, wherein said output voltage is indicative of direction of rotation of said target wheel in relation to said single differential sensor;
• wherein said predetermined distance is less than one-quarter said predetermined pitch.