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:
May. 08, 2001
Filed:
Feb. 26, 1999
Hisashi Suganuma, Saitama, JP;
Pioneer Corporation, Tokyo, JP;
Abstract
A digital FM demodulation circuit which samples an input analog FM signal and digitally detects the sampled input signal has an arctangent circuit into which a second signal that is delayed from the sampled input signal by a constant time, and a third signal that is different in phase by 90 degrees from the second signal are input, and which outputs a corresponding arctangent value based on a result of a division of the two input signals. The arctangent circuit has: roundoff means for sequentially rounding the division result to one of plural typical values; and a ROM address unit for performing a control in which an arctangent value corresponding to the rounded typical value is selected from a ROM table containing arctangent values of the typical values, and the selected arctangent value is output.