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:
May. 03, 2011
Filed:
Oct. 18, 2006
Mahibur Rahman, Lake Worth, FL (US);
John J. Parkes, Jr., Boynton Beach, FL (US);
James J. Riches, Lake Worth, FL (US);
Mahibur Rahman, Lake Worth, FL (US);
John J. Parkes, Jr., Boynton Beach, FL (US);
James J. Riches, Lake Worth, FL (US);
Freescale Semiconductor, Inc., Austin, TX (US);
Abstract
A digital tuning system () for changing a cutoff frequency of an analog filter () includes digital synthesizers (and) for producing a two-tone calibration signal () applied to an input of the filter after a quality factor of the filter is increased. The filter includes at least one R/C circuit with two resistors (and) for changing the quality factor and arrays (and) of capacitors for changing the cutoff frequency. The amplitude of the magnitude responses (and) of the filter to each tone (and) is measured by a two discrete Fourier transform single-frequency bin power detection circuits (and) while the filter is sequenced through a plurality of capacitance settings. An optimal capacitance for the R/C circuit is selected by comparing, to a pre-selected value, a difference between the responses of the filter to each tone, for each capacitance setting.