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:
Aug. 04, 1998
Filed:
Aug. 12, 1997
James Robert Kelton, Oak Park, IL (US);
David Paul Gurney, Algonquin, IL (US);
Michael Russel Mannette, Bloomingdale, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
An improved automatic frequency correction acquisition system utilizes an automatic frequency correction (AFC) loop (22) having an acquisition mode in which an estimate of the frequency offset of a received carrier signal is rapidly acquired and a tracking mode in which the automatic frequency correction loop more accurately follows changes of the frequency offset. The AFC is switchable in response to predetermined control signals between the acquisition mode and the tracking mode. A carrier to impairment ratio estimator (36) is coupled with the automatic frequency correction loop (22) for estimating the carrier to impairment ratio of the incoming carrier signal. An automatic frequency correction controller (30) is coupled with the automatic frequency correction loop (22) and with the carrier to impairment ratio estimator (30) and is responsive to the carrier to impairment ratio estimate being at or above a preselected threshold value for producing a tracking control signal (24) comprising one of the predetermined control signals. The automatic frequency correction loop (22) is responsive to the tracking control signal (24) for switching from the acquisition mode to the tracking mode.