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:
Nov. 06, 2012
Filed:
Jul. 28, 2009
Yuzo Seo, Utsunomiya, JP;
Yuzo Seo, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A detection apparatus detecting an error component contained in two signals (A, B) approximated by a cosine and sine functions representing an object position, the detection apparatus including an arithmetic portion () which reduces an error contained in the signals (A, B) based on an error prediction value to output two error correction signals (A*, B*), a phase arithmetic portion () which calculates a phase (θ) based on the error correction signals (A*, B*), an arithmetic storage unit () which stores the error correction signals (A*, B*) and a plurality of sampling values of the phase (θ), and a Fourier transform portion () which obtains coefficients α, β, γ, and δin the following two expressions:+αcos θ+βsin θ+ . . . +αcossin+γcos θ+δsin θ+ . . . +γcossin(k≧2)wherein the arithmetic portion () updates the error prediction value using the coefficients.