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:
Oct. 29, 1996
Filed:
May. 18, 1995
John A Eisenberg, Los Altos, CA (US);
Spectrian, Inc., Mountain View, CA (US);
Abstract
An RF power amplifier utilizes predistortion to improve linearity of the amplifier. RF carrier signals from an input terminal are coupled to a power amplifier through a first amplitude and phase adjustor serially connected with a predistortion amplifier having signal distortion characteristics of the power amplifier. A first control loop includes a subtractor for receiving RF carrier signals from the input terminal and signals from the predistortion amplifier and producing a predistortion signal for applying to the power amplifier through a path including a second amplitude and phase adjustor and an error amplifier. A first loop control unit receives the RF carrier signals from the input terminal and the distortion signal and produces control signals for the first amplitude and phase adjustor for minimizing RF carrier signals in the predistortion signal. A second control loop including a second loop control unit receives signals from the output of the power amplifier and signals from the predistortion amplifier and generates control signals for the second amplitude and phase adjustor to minimize distortion in signals at the output of the power amplifier. Each of the control units includes a digital signal processor for generating control signals for the amplitude and phase adjustor, and frequency reduction circuitry is provided in each of the control loops for reducing the frequencies of input signals to within the range of the digital signal processors.