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:
Aug. 05, 1997
Filed:
Mar. 30, 1994
Weimin Sun, Ikoma-gun, JP;
Icom Incorporated, Osaka, JP;
Abstract
A 90-degree digital phase shift network includes at least two all-pass digital filters which have a phase difference of 90 degrees therebetween. These digital filters are adapted to receive the same signal. Each of the all-pass digital filters has phase characteristics .theta.(.omega.) given by ##EQU1## where T represents a sampling period, P.sub.i a real number indicative of a filter coefficient, .omega. the angular frequency, m a weight variable, n'=n/2 (n=even number), n'=(n+1)/2 (n=odd number), n an order of a 90-degree digital PSN, m being a positive value other than 1, and satisfying .vertline.2m.omega..vertline./.vertline.P.sub.i .vertline.<1 when .omega.T is sufficiently lower than 1, while satisfying .vertline.-P.sub.i .omega.T.sup.2 .vertline./2m<1 when .omega.T is substantially equal to .pi..