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:
Apr. 17, 2001
Filed:
Jan. 13, 2000
Ryoji Abe, Yokohama, JP;
Matsushita Electric Industrial., Ltd., Osaka, JP;
Abstract
A filter device includes a first section for receiving data of a desired cutoff frequency. A second section operates for deciding whether the desired cutoff frequency is in a predetermined low frequency band or a predetermined high frequency band. The predetermined low frequency band is lower in frequency than the predetermined high frequency band. A third section stores data of filter coefficients corresponding to different cutoff frequencies in the predetermined low frequency band. A fourth section stores data of precalculated basic coefficients corresponding to different cutoff frequencies in the predetermined high frequency band. The precalculated basic coefficients are equal to values resulting from a part of calculation to provide final filter coefficients. A fifth section operates for calculating final filter coefficients from precalculated basic coefficients through a coefficient expanding process. In cases where the second section decides that the desired cutoff frequency is in the predetermined low frequency band, data of filter coefficients corresponding to the desired cutoff frequency are read out from the third section, and are set in a filtering section. In cases where the second section decides that the desired cutoff frequency is in the predetermined high frequency band, data of precalculated basic coefficients corresponding to the desired cutoff frequency are read out from the fourth section. Then, the fifth section is caused to calculate final filter coefficients from the read-out precalculated basic coefficients, and data of the calculated final filter coefficients are set in the filtering section.