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. 02, 1988
Filed:
Jul. 29, 1986
Ronald J Canniff, Naperville, IL (US);
American Telephone and Telegraph Company AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
A method and apparatus for generating accurate digital representations of one or more sine waves. A digital signal processor is used to generate the sample digital values, spaced at period T, of a sine wave of frequency F, F<1/2T, using recursive methods. The magnitude of the generated sample values is stabilized and controlled by normalizing the recursively generated samples from time to time, but not necessarily after each recursive calculation. Methods are described for generating values based on the values of two previously generated samples using the recursion formula: y(n)=y(n-1)2 cos.omega.-y(n-2) where .omega.=2.pi.FT and y(n), y(n-1) and y(n-2) represent three consecutive sample values. The normalizing factor, used for multiplying a recursively generated sample value to stabilize the amplitude, associated with this calculation is ##EQU1## where A is the desired amplitude. Methods are also described for generating two sine waves of the same frequency but displaced in phase, and for generating frequency and phase-shift keyed sine waves. Advantageously, these methods and apparatus minimize the resources required for performing the generation of the sine waves.