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:
Mar. 01, 1994
Filed:
Mar. 02, 1993
Edwin R Twitchell, Quincy, IL (US);
Daniel B Talbot, Hudson, MA (US);
Harris Corporation, Melbourne, FL (US);
Abstract
Spurious frequency components from the output signal of a direct digital synthesizer are reduced with minimum degradation of the fundamental frequency of the output signal. The synthesizer has a phase accumulator for receiving digital multibit modulation data words from a source, a periodic wave function converter for converting the modulation data words into digital waveform data words and a digital-to-analog converter for converting the digital waveform data words into an analog signal which serves as the output signal. The output signal has a frequency and waveform dictated by the modulation data words. Reduction of spurious frequency components is achieved by generating a dither waveform representing a band limited waveform. The dither waveform is summed with the modulation data words prior to application to the wave function converter to provide a dither modulated analog output signal. A sampled dither signal is combined with the dither modulated analog output signal in such a manner that the dither waveform is cancelled from the fundamental waveform of the analog output signal.