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:
Jun. 06, 2006
Filed:
May. 06, 2004
Hubert Schlapp, Ebern, DE;
Johan D. Overby, Sunnyvale, CA (US);
Hubert Schlapp, Ebern, DE;
Johan D. Overby, Sunnyvale, CA (US);
Metrotech Corporation, Inc., Santa Clara, CA (US);
Abstract
When cables run side by side over a longer distance, an alternating-current signal used for cable location can couple or 'bleedover' to neighboring cables. The coupled current flowing in the neighboring cable creates field distortion and makes position determination of the targeted cable difficult. The resulting magnetic field of both (or more) cables has a non-circular shape and is commonly known as a distorted field. Established methods for finding the position of the cable under investigation lead to inaccuracies or even wrong locates. The method described herein eliminates the field distortion that is due to the coupled cables by demodulating a phase reference signal placed on the cable by a transmitter into two signal strength constituents. The inphase signal represents the field strength of the targeted conductor and is substantially free of field distortion. The other quadrature signal contains the component of the field associated with distortion.