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:
Oct. 13, 1987
Filed:
Sep. 30, 1985
Applicant:
Inventors:
Assignee:
NEC Corporation, Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
H04L / ;
U.S. Cl.
CPC ...
375 62 ; 332 / ; 375 44 ; 375 49 ; 375 51 ;
Abstract
A FSK code with reduced high frequency content is generated. First through fourth waveforms are provided to a selector which selects one of the four waveforms in accordance with a control signal which, in turn, is generated in accordance with a state indication signal identifying the presently selected one of the four waveforms. A D/A converter converts the selected digital waveform data to an analog waveform signal. First and second of the digital waveform data represent +sin .theta. and -sin .theta., and third and fourth of the digital waveform data represent +f(.theta.) and -f(.theta., respectively, where ##EQU1## wherein 0.ltoreq..theta..ltoreq.2.pi. and a, b and c are nonzero coefficients.