METAL DETECTOR FOR LOCATING METAL OBJECTS
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Abstract
The invention relates to a method for locating metal or metal-containing objects and materials, currents in at least two emission coils being regulated in relation to each other such that a reception coil output signal received by at least one reception coil or average values of demodulation phases generated from the reception coil output signal are regulated in relation to each other continuously to be “zero” even when exposed to metal. The amplitude(s) of the required controlled variable(s) is/are detected as a value by demodulation, preferably at least at 0° and at a demodulation which is set off by 90° and is/are equalized, thereby improving the method such as to allow a reliable detection of an object to be detected even if other metal objects are present in the area of detection.
15 Citations
13 Claims
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1-12. -12. (canceled)
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13. A method for locating metal or metal-containing objects and materials, comprising:
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mutually regulating currents in at least two transmission coils in such a way that a receiving coil output signal received by at least one receiving coil or average values of receiving coil output signals generated from demodulation phases are continuously mutually regulated to “
zero”
even under the influence of metal,wherein an average value of the receiving coil output signal demodulated in a first demodulation phase is of a same size in a stabilized state to an average value of the receiving coil output signal demodulated in a further demodulation phase that is shifted by 90°
to the first demodulation phase, andwherein the amplitude of control variables required for a regulation to “
zero”
are acquired and equalised by means of a multiplier.
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Specification