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:
Sep. 24, 1991
Filed:
Dec. 15, 1988
Abstract
A transfer function is determined in accordance with an amplitude characteristic and a phase characteristic. The transfer function is subjected to inverse Fourier transform. An imaginary part of a result of the inverse Fourier transform is set to zero and thereby the result of the inverse Fourier transform is converted into a converted result. The converted result is subjected to Fourier transform. The amplitude characteristic and the phase characteristic are updated in accordance with a result of the Fourier transform. Such processes are reiterated. A primary desired amplitude characteristic is corrected in accordance with the finally-obtained amplitude characteristic so that the primary desired amplitude characteristic is converted into a final desired amplitude characteristic. A final desired phase characteristic is determined in accordance with the finally-obtained phase characteristic. A second transfer function is determined in accordance with the final desired amplitude characteristic and the final desired phase characteristic. The second transfer function is subjected to inverse Fourier transform. Filter factors are calculated from a real part of a result of the inverse Fourier transform of the second transfer function. The calculated filter factors are set in a FIR digital filter.