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:
Jan. 23, 1990
Filed:
Jan. 15, 1988
Seiichi Ishikawa, Osaka, JP;
Masaharu Matsumoto, Osaka, JP;
Katsuaki Satoh, Osaka, JP;
Akihisa Kawamura, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An apparatus for calculating a filter factor for a digital filter which can be simply constructed and in which the time period for calculation can be shortened as compared with conventional techniques. The apparatus has an input circuit for inputting a desirable frequency property, a division circuit for dividing the inputted frequency property into a plurality of frequency bands, and a calculating circuit for obtaining filter factors for realizing a frequency property of each of the divided frequency bands. The input circuit inputs the frequency property with a frequency resolution corresponding to the number of the filter factors. The division circuit performs a correction for a division so that the frequency property becomes zero from a frequency over the high cut-off frequency of a band-pass filter toward the Nyquist frequency of the frequency band corresponding to the transversal filter, the Nyquist frequency being 1/2 of the sampling frequency. The calculating circuit has a transformation unit for performing a Hilbert transformation or a linear phase transformation with respect to the respective frequency properties divided by the division circuit.