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:
Feb. 23, 1993
Filed:
Oct. 15, 1991
Takashi Shimada, Hyogo, JP;
Satoru Inoue, Hyogo, JP;
Takaaki Maekawa, Hyogo, JP;
Akio Jitsumori, Hyogo, JP;
Japan National Oil Corporation, Tokyo, JP;
Abstract
A receiving apparatus for receiving information transmitted from a bottomhole to a surface by means of electromagnetic waves. The receiving apparatus includes a receiving antenna for receiving a transmitted signal from the bottomhole, a noise detector for detecting noise current received by the receiving antenna, and a noise canceller for removing noise components received by the receiving antenna by comparing an output signal from the receiving antenna and an output signal of the noise detector. The noise canceller is a noise canceller using parallel adaptive filters, and includes a plurality of adaptive filters arranged in parallel fashion, an adder for summing output signals of the plurality of adaptive filters, and a subtracter for subtracting an output signal of the adder from a main input signal.