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:
Dec. 13, 2005
Filed:
Sep. 05, 2001
Leonard Rexberg, Hässelby, SE;
Bernt Johansson, Kista, SE;
Leonard Rexberg, Hässelby, SE;
Bernt Johansson, Kista, SE;
Telefonaktiebolaget LM Ericsson (publ), Stockholm, SE;
Abstract
A method is disclosed for obtaining high throughput linearity using a pre-distorter in front of a RF power amplifier, for instance a multi-carrier power amplifier (MCPA) for a communications system. The method can be carried out off-line to thereby save costs and components otherwise needed for a common on-line feed back. In a first step calibration is performed by measuring by an off-line spectrum analysis an output spectrum of the power amplifier and simultaneously applying a known input signal. As a next step digitized parameters characterizing the power amplifier are calculated in the frequency domain by comparing spectrum points between input spectrum and output spectrum. Thereafter calculated and weighted digitized parameters are transferred to a pre-distorting device. In a third step the known signal spectrum is transferred to the pre-distorting device feeding its output signal together with the original known signal spectrum to the power amplifier input thereby compensating for power amplifier non-linearity and minimizing inter-modulation products. Finally in a fourth step an uncompensated known input spectrum is compared with a corresponding compensated output spectrum of the power amplifier and the steps of calibration calculation are repeated until a best optimization input signal to the power amplifier regarding the inter-modulation products of the output signal has been achieved.