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, 2009
Filed:
Sep. 12, 2005
Satoshi Furuta, Tokyo, JP;
Naoki Hongo, Tokyo, JP;
Satoshi Furuta, Tokyo, JP;
Naoki Hongo, Tokyo, JP;
Hitachi Kokusai Electric Inc., Tokyo, JP;
Abstract
An amplifier apparatus for providing a pre-distortion to perform a distortion compensation, wherein even if the frequency of occurrence of levels around the input signal peak is small, a distortion compensation table is efficiently updated so as to improve the performance of the distortion compensation. The compensation values of a distortion compensation table () are divided into a first group of compensation values corresponding to large input levels that lead to large output distortions and a second group of compensation values corresponding to the other small input levels. If a level detected by a level detecting part () exceeds a threshold value, a control part () updates the first group of compensation values. Otherwise, the control part () updates the second group of compensation values. In this way, the updating process can be effectively performed even for signals having small frequencies of occurrence of the peak values of the signal levels as in the CDMA or OFDM system, thereby improving the performance of the distortion compensation.