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:
Jun. 18, 1985
Filed:
Sep. 15, 1980
Masao Kasuga, Sagamihara, JP;
Victor Company of Japan, Limited, Yokohama, JP;
Abstract
A digital filter having a band-pass filter characteristic or a band-elimination characteristic is constructed by a designing procedure comprising a step in which a function H(z) is obtained from a Z-transform of a bi-quad transfer function H(s) in a Laplace transfer form comprising conjugate pairs of poles and zeros, and establishing a center frequency of the filter characteristic from the radius of a circle in the s-plane in which the poles and zeros of the bi-quad transfer function H(s) are on the same circle, a step in which a quality factor Q of the filter characteristic is established so as to satisfy the following two equations (I) and (II) in which .sigma..sub.1 is the real-axis projection part and .omega..sub.1 is the imaginary-axis projection part of the above two poles in the s-plane, and .sigma..sub.2 is the real-axis projection part and .omega..sub.2 is the imaginary-axis projection part of the above two zeros, and a step in which a gain at the center frequency of the filter characteristic is established from a ratio .sigma..sub.2 /.sigma..sub.1 of the real-axis projection part .sigma..sub.1 of the poles and the real-axis projection part .sigma..sub.2 of the zeros in the s-plane ##EQU1##