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:
Jul. 04, 1978
Filed:
Jun. 10, 1977
Benjamin C Alm, Jr, Arnold, MD (US);
Francis W Hopwood, Severna Park, MD (US);
Robert A Jelen, Arnold, MD (US);
John P Muhlbaier, Joppa, MD (US);
Joseph F Wright, Jr, Columbia, MD (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
A digitally controlled microwave phase lock loop for switching rapidly from one lock frequency to another is disclosed. A digital word corresponding to a desired input voltage for a selected frequency is converted to an analog voltage for application to the coarse tuning port of the loop's voltage controlled oscillator. Prior to switching to another frequency, the error voltage for the fine tuning port is compared with a zero error reference voltage. The least significant bit of the digital word for such frequency is increased or decreased by one depending on the direction difference between the compared voltages. This incrementally changed word controls the coarse tuning voltage during the next selection of the particular frequency. The system is initialized by repetitively selecting each of the possible frequencies until the digital word for each selected frequency is within one increment of the zero error reference voltage for the fine tuning port.