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. 11, 1991
Filed:
Dec. 20, 1989
Stephen P Caldwell, Columbia, MD (US);
David S Korn, Washington, DC (US);
Francis W Hopwood, Severna Park, MD (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
An oscillator circuit is coupled to receive first and second reference signals and includes a voltage-controlled oscillator for generating an oscillating signal. A difference frequency calculation circuit is coupled to the voltage-controlled oscillator to produce a count signal corresponding to a difference in frequency between the oscillating signal and the first reference signal. A feedback circuit is coupled to the difference frequency calculation circuit and coupled to receive the second reference signal which corresponds to a predetermined frequency for the oscillating signal. The feedback circuit provides a control signal as an input to the voltage-controlled oscillator to control the frequency of the oscillating signal. The method for tuning the voltage-controlled oscillator which generates the oscillating signal includes a step of calculating a difference in frequency between the oscillating signal and a first reference signal, and generating a count signal corresponding to the difference in frequency. The count signal is compared to a reference count signal corresponding to a predetermined frequency for the oscillating signal, and an error signal is generated based on the results of the comparison. The error signal and a prepositioning signal corresponding to the predetermined frequency for the oscillating signal are added to generate a control signal which is provided to the voltage-controlled oscillator to control the frequency of the oscillating signal.