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:
Sep. 26, 2006
Filed:
Oct. 14, 1998
Harri Kimppa, Salo, FI;
Markus Pettersson, Turku, FI;
Kjell Östman, Salo, FI;
Nokia Mobile Phones Limited, Espoo, FI;
Abstract
The invention relates to a calibration method and a calibration arrangement for an active filter intended to be used especially in portable radio apparatus. The filter () according to the invention is an active RC filter and it is integrated except for one or more of its capacitances or one or more of its resistances. Advantageously the highest capacitance or the highest resistance is left unintegrated. When using an external capacitance, the principle of the calibration is as follows: The integrated resistances are corrected using a common coefficient such that the external capacitance together with the integrated resistances produces the correct time constants (). Then the integrated capacitances are corrected using a common coefficient such that they together with the internal resistances that were corrected in the previous phase produce the correct time constants (). If the filter comprises multiple circuit stages, the two-phase calibration process described above is repeated for each circuit stage.