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:
Apr. 07, 1998
Filed:
Dec. 02, 1996
Scott R Humphreys, Boynton Beach, FL (US);
Darrell E Davis, Sunrise, FL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A PLL circuit (401), including a VCO (420) having a trimming port (418) and a tuning port (416), a PLL controller (404), a variable voltage source (408), a voltage measuring circuit (426) and a multiplexer (412, 414, 428), performs automatic trimming of the VCO (420). The PLL circuit (401) accomplishes this by initiating a trimming mode that controls the multiplexer so that it couples the output of the PLL controller (404) to the trimming port (418), and the output of the variable voltage source (408) to the tuning port (416), thereby to phase lock the VCO (420) to the reference frequency signal (421). The PLL circuit (401) then measures, by way of the voltage measuring circuit (426), a voltage at the trimming port (418), switches the PLL circuit (401) to an operational mode, and then adjusts the variable voltage source (408) to be substantially equal to the voltage measured.