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. 31, 1990
Filed:
Aug. 29, 1988
Michael McGinn, Scottsdale, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A circuit for providing rapid charge and discharge of a capacitive load is utilized in conjunction with a phase detector error signal output generated in a television video demodulator system for controlling the operating frequency of the local oscillator. The circuit comprises a pair of comparators each biased to a respective threshold level whereby the first comparator provides an output signal when the error signal supplied thereto from the phase detector exceeds its threshold level and the second comparator provides an output signal when the error signal is less than its threshold level. An additional circuit is coupled to the outputs of the pair of comparators and is responsive to the first comparator for sourcing current to the capacitive load while being responsive to the second comparator for sinking current from the load. The capacitive load may be the AFC filter of an AFC loop of a television receiver wherein the local oscillator frequency is controlled by the voltage developed across the filter.