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:
Nov. 06, 2012
Filed:
Dec. 03, 2010
Gregory A. Fung, Fremont, CA (US);
Gregory A. Fung, Fremont, CA (US);
Linear Technology Corporation, Milpitas, CA (US);
Abstract
An actual linear amplifier distorts an input signal, such as an RF signal, and generates third order intermodulation (IM3) products. A single-port predistortion circuit is connected at a single node of an input line to the amplifier via an AC coupling capacitor. The fundamental frequency of the input signal is applied to a forward biased diode junction. The current through the diode is applied to a second capacitor. The appropriate setting of a tuning device, such as a tunable resistor or a tunable capacitor, causes the predistortion circuit to invert the second harmonic generated by the diode. The inverted second harmonic signal is applied to the single node of the input line to add predistortion to the signal applied to the amplifier. The predistortion cancels or substantially reduces the IM3 products at the output of the amplifier.