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:
Feb. 13, 1990
Filed:
Dec. 14, 1987
Richard J Kerr, San Diego, CA (US);
Lindsay A Weaver, San Diego, CA (US);
Qualcomm, Inc., San Diego, CA (US);
Abstract
A method and apparatus for reducing spurious output noise in digital frequency synthesizers employing sine amplitude converters connected to Digital-to-Analog converters to generate analog waveforms from sine amplitude data. Random or pseudorandom numbers having a value equal to or less than plus or minus one-half of a minimum quantization step or value change for the sine amplitude data are generated and added to the sine amplitude data with the resulting sum being transferred to the Digital-to-Analog converter. In one embodiment, a summation circuit is connected between an output of the sine function converter and an input of the Digital-to-Analog converter and also has a second input connected to a pseudorandom number generator which provides Pseudorandom numbers varying in value over a range of .+-.1/2.sup.n+1 times a least significant step value, or bit for base 2, of a corresponding Digital-to-Analog input data value where n is greater than or equal to 1.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile