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:
Oct. 24, 1989
Filed:
Dec. 02, 1988
Geoffrey W Perkins, Chandler, AZ (US);
Motorola Inc., Schaumburg, IL (US);
Abstract
A system for automatically tracking and locking to an applied scanning input signal the frequency of which may vary over a range of frequencies includes a PLL comprising a VCO and phase detector as well as a digital frequency counting section which forms a closed loop with the VCO. The VCO is operated preferably at 32 times the frequency of the applied input signal and provides a clock signal to the digital section which also receives the input signal. The digital section includes a counter and decoder-latch wherein the clock signal that is supplied to the counter is used to measure the frequency of the applied input signal. Counting and decoding result on alternating periods of the applied input signal such that the decoder-latch decides if the count is too low, too high or within the range of the PLL and controls the operating frequency of the VCO to find and maintain phase lock.