| 摘要 |
<p>A measuring apparatus for detecting a metal object includes two emission coils, a magnetoresistive measuring device, and a control device. The emission coils are configured to produce superimposed magnetic fields. The magnetoresistive measuring device is in the region of both magnetic fields, and is configured to emit an output signal which is dependent on the magnetic field. The control device is configured to supply the emission coils with alternating voltages such that the value of the alternating voltage component of the output signal, which is time synchronized with the alternating voltages, is minimized. The control device is further configured to detect the object when the ratio of the alternating voltages does not correspond to the distances between the magnetoresistive measuring device and the emission coils.</p> |
