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:
Jul. 27, 1993
Filed:
Mar. 30, 1992
James S Irwin, Paige, TX (US);
Robert C Ledzius, Austin, TX (US);
Dhirajlal N Manvar, Austin, TX (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A sigma-delta digital-to-analog converter (20) reduces even order distortion, such as a DC offset, in an output signal by chopping the output signal alternately with set and reset pulses. The sigma-delta digital-to-analog converter (20) includes a sigma-delta modulator (25), a chop circuit (261) associated with a corresponding bit of the sigma-delta modulator (25), and an output buffer (264) for providing the output signal. The chop circuit (261) alternately inserts first and second logic levels into an output data stream of the sigma-delta modulator (25) before providing it to the output buffer (264). Even-order distortion is eliminated with only a tolerable attenuation of the output signal.