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:
Jun. 11, 2002
Filed:
Jul. 01, 1998
Robert Edmund Grange, San Diego, CA (US);
Donald Brian Eidson, San Diego, CA (US);
Conexant Systems, Inc., Newport Beach, CA (US);
Abstract
An envelope feedforward technique is described that provides efficient, variable-power, linear amplification of an input signal. An input signal having phase and amplitude components is separated (decomposed) into an FM portion and an envelope portion. The FM portion contains the high frequency phase and frequency information from the input signal. The envelope portion contains the low frequency amplitude information from the input signal. An envelope combiner uses the envelope signal to amplitude-modulate the FM signal to produce an output signal. Spectral regrowth of the output signal is reduced by adjusting the relative time delays in the signal path of the envelope signal and the FM signal such that the FM signal and the envelope signal arrive at the envelope combiner at the same time. The envelope feedforward technique may be used to increase battery life in a handheld mobile RF unit such as a cellular telephone. An efficient Class D switching amplifier is constructed using a dual-gate FET by applying the envelope signal to the first gate to vary the transconductance of the FET and by applying the FM signal to the second gate to switch the FET on and off.