The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 16, 1990
Filed:
Jul. 22, 1987
Erkki I Leinonen, Vantaa, FI;
Kari T Aittoniemi, Espoo, FI;
Outokumpu Oy, Helsinki, FI;
Abstract
The invention relates to a method and an apparatus for detecting metal objects in a metal detecting apparatus using impulse techniques. The metal detector comprises a compensation circuit arranged in between the transmitter system (13) and the receiver system (14) in order to compensate the mutual inductance between the transmitter (11) and the receiver (12). The compensation circuit is advantageously operated so that the signal caused by the metal object in this detector is measurable during both at least two measuring sequences (21,22) located within the range of the cut-off peak of the transmitter current and during at least one measuring sequence (23) located outside the range of the cut-off peak of the transmitter current.