Patent ID: 7362094

Claim:
Apparatus for detecting passing magnetic articles and providing a magnetic article detector output signal indicative of the passing magnetic articles comprising: a magnetic field sensor providing a signal proportional to an ambient magnetic field; a first circuit responsive to the magnetic field sensor signal to provide a first output signal indicative of the passing magnetic articles, wherein the first output signal provides the magnetic article detector output signal during a first time interval; a second circuit responsive to the magnetic field sensor signal to provide a second output signal indicative of the passing magnetic articles, wherein the second output signal provides the magnetic article detector output signal during a second time interval following the first time interval; a phase comparator responsive to the first output signal and the second output signal to provide a control signal indicative of a change of a phase relationship between the first output signal and the second output signal; and a switch having a first input responsive to the first output signal, a second input responsive to the second output signal, and an output at which the magnetic article detector output signal is provided, wherein the switch is controlled by the control signal.