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. 07, 1979
Filed:
May. 05, 1978
Glen D Rattlingourd, Salt Lake City, UT (US);
John W Zscheile, Jr, Murray, UT (US);
Sperry Rand Corporation, New York, NY (US);
Abstract
Electronic digital apparatus for computing an approximation of the arctangent of a given tangent number, N, being in the range of 0 to 1 and in binary form, operates in two stages to provide a solution of the expression: ##EQU1## During the first stage, steps are taken by the apparatus to find out where within the range of 0 to 1, divided preferably into four equal increments, the known tangent number N is located. When the correct increment represented by one of a plurality of increment numbers I.sub.j stored in a ROM unit of the apparatus is found, then one of a like plurality of center numbers C.sub.k of that increment also stored in the ROM unit may be readily selected, as can also be the corresponding one of a plurality of stored numbers A.sub.i representing the arctangents of the stored center numbers C.sub.k. During the first stage, the product number C.sub.k (N) is also formed. In the second stage of operation of the apparatus, the dividend and divisor numbers N-C.sub.k and 1+C.sub.k (N) are first calculated. The quotient number,