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:
Sep. 18, 2001
Filed:
Feb. 04, 2000
Yoshihiro Hanada, Yokohama, JP;
Akira Toyama, Chigasaki, JP;
Nippon Precision Circuits, Inc., Tokyo, JP;
Abstract
A delta-sigma D/A converter has a quantizer, a thermometer code converter portion, and an odd/even bit-interchanging portion. The quantizer produces a first digital signal. The thermometer code converter portion and odd/even bit-interchanging portion divide the output level of the first digital signal such that it is represented by the sum of the output levels of second and third digital signals. Each of the second and third digital signals has an output level obtained by dividing the output level of the first digital signal by a factor of 2 or an integer close to it. During the former half of each sampling interval, first and second adders produce, respectively, a level signal corresponding to the second digital signal and an inverted level signal corresponding to an inversion of the third digital signal. During the latter half of the sampling interval, the adders produce, respectively, a level signal corresponding to the third digital signal and an inverted level signal corresponding to an inversion of the second digital signal. An operational amplifier subtracts the inverted level signal from the level signal and produces an analog signal corresponding to the output level of the first digital signal.