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:
Jun. 13, 1978
Filed:
Aug. 30, 1976
William George Crouse, Raleigh, NC (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A digital-to-analog converter method and apparatus is disclosed which utilizes a hybrid technique of combined pulse width and pulse rate modulation to achieve improved performance with reduced logic and circuitry requirements. Lower order bits of an N-bit digital data input for conversion to a corresponding analog output voltage level are treated in a manner similar to pulse rate modulation approaches utilized previously. High order bits are handled together in a variant form of pulse width (duration) modulation in which the pulse width required to generate the given analog voltage level corresponding to the high order digital bit inputs is divided into a fixed number of slices in a given sample time, each slice having a width or duration of pulse output which is variable in itself in correspondence to a function of both the high and low order bit value inputs. A low pass filter or integrator combines all of the pulses in a given sample to produce the analog voltage level output.