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. 19, 1991
Filed:
Nov. 27, 1989
Raymond C Blackham, Penn Valley, CA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
Distortion in a digital-to-analog converter (DAC) is eliminated by adding a digital random number to each sample of the digital signal, converting the sum into analog form, and subtracting from this analog sum the analog counterpart of the digital random number. The result is the analog counterpart to the input digital signal. The conversation of the summed digital signal and the random number into analog form can be performed by two conventional DACs. For any digital input sample, the output of each DAC is equally likely to contain any of the possible distortion errors produced by the DAC. (An exception is the most significant output bit of the DAC that processes the summed signal, an exception that may be handled by stripping off the most significant bit and applying it to a one-bit DAC.) The error signal at the output of each of the two DACs is thus a random sequence (i.e. noise) of DAC distortion errors. The time average of this noise signal is a small offset error which, if desired, can be removed by subsequent processing stages.