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:
Jul. 01, 1997
Filed:
Mar. 28, 1995
Huong M Hang, San Jose, CA (US);
Spectrian, Inc., Mountain View, CA (US);
Abstract
To reduce the size and power dissipation of a feed-forward amplifier, two identical high power amplifiers in a quadrature combined configuration function both as the main amplifier and as the error amplifier. The feed-forward amplifier has two control loops to increase amplifier linearity and reduce intermodulation distortion. A first loop is provided to subtract a properly scaled and delayed sample of the amplifier input spectrum from a scaled and phase shifted sample of its output spectrum which contains intermodulation distortion. The result of this subtraction (if the samples are maintained at the same amplitude and 180 degrees out of phase) is a signal rich in the intermodulation products of the amplifier. A differential phase-amplitude comparator which compares the signals prior to and after amplification and generates control signals for amplitude and phase trimmers for the signal prior to the amplifier and thus maintains the required equal amplitude and 180 degree phase relationship required for carrier cancellation. A second loop is provided to reduce distortion of the error signal due to effects of the amplifier.