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:
Nov. 05, 1991
Filed:
Dec. 21, 1990
Applicant:
Inventors:
Irl W Smith, Concord, MA (US);
Manfred J Schindler, Newton, MA (US);
Assignee:
Raytheon Company, Lexington, MA (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
H04L / ;
U.S. Cl.
CPC ...
332103 ; 332104 ;
Abstract
A direct digital synthesizer (DDS) includes a phase accumulator which generates phase words periodically and means for changing the phase of an RF signal. In a preferred embodiment, a DDS includes a pair of phase shifter channels having inputs and outputs coupled in parallel by make before break RF switches. The use of the dual phase shifter channels and make before break RF switches provides relatively smooth phase advance while eliminating fly-back transitions. This arrangement reduces excessive noise power in the output signal.