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. 20, 1990
Filed:
Dec. 16, 1988
David E Borth, Palatine, IL (US);
James F Kepler, Northbrook, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
There is provided a method of and apparatus for Automatic Frequency Control (AFC) of pure sine waves (PSW). It comprises discriminating to detect frequency differences between a received pure sine wave and a reference frequency, integrating the frequency differences to average the differences, and adjusting the reference frequency to eliminate the frequency difference. It is further characterized by digitizing, in quadrature, the received pure sine wave, mixing the received pure sine wave with a complex sinusoid to translate the pure sine wave to baseband, quadrature filtering the mixed sine wave, cross-product discriminating to detect frequency differences between a received pure sine wave and a reference frequency, integrating the frequency differences to average the differences, selectively calculating the mean variance between the pure sine wave and the reference frequency, and adjusting the reference frequency of a Voltage Controlled Oscillator to eliminate the frequency difference.