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. 14, 1992
Filed:
Oct. 09, 1990
Georges Karam, Paris, FR;
Hikmet Sari, Creteil, FR;
U.S. Philips Corporation, New York, NY (US);
Abstract
Predistortion arrangement (9) for a digital transmission system transmits complex input data of a constellation by means of a modulator (14) and a power amplifier (15) which distorts the data. The arrangement comprising a predistortion circuit (11) which predistorts the input data in opposite sense before they pass through the amplifier and a transmit filter (10) which applies oversampled filtered data encoded with 2N bits to the predistortion circuit (11) at the rate k/T. The predistortion circuit (11) first determines approximate values of the predistorted data on the basis of a portion of 2M bits of the field of 2N bits (M<N), which data are thereafter revised with the aid of the remaining portion of said field. The predistortion circuit includes for each channel a memory (112) addressed by the field of M bits which produces the approximate values of the predistorted data and an interpolation circuit (111) which derives therefrom the revised predistorted data.