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. 26, 1994
Filed:
Mar. 20, 1992
Derek L Tattersall, Jr, Wheeling, IL (US);
James F Long, Glen Ellyn, IL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
Briefly described the present invention is a feed forward amplifier network (200) employing a frequency swept pilot tone signal (212) in order to reduce the distortion generated by the network's power amplifier (202). Initially a composite input signal (216) comprising either wide (520) and/or narrow (510) bandwidth modulation formats is input into the network (200). In addition, the frequency swept pilot tone (212), generated for example by a variable frequency oscillator (213), is injected into the input path of the power amplifier (202). Thereafter, distortion cancellation is employed to generate an amplified output signal (217) having output components (510,520) which replicate those within the input signal (216). Thereafter, pilot tone power is detected (by 215) within the amplifier passband where the output components (510,520) are absent, in order to ascertain the average pilot tone power remaining within the amplified output signal (217). In response to this detection, various amplifier network characteristics are adjusted (by 214, 208 and 209) in order to reduce the amount of pilot tone at the amplifier network output (217).