Powerwave Technologies, Inc.

Sandip Patel

Charles R Gentzler

Richard D Posner

Do B Shin

Kwang Kim

Wayne Roberts

Stefan Klein

A method and apparatus for reducing out-of-band frequency components of an RF amplified input signal, the amplified signal having both in-band frequency components and out-of-band frequency components, employ a feedforward network in which a microprocessor can sweep a frequency generator output connected to a mixer, the other input of the mixer being the amplified output, to find the carrier frequency of the input signal, and thereafter modify or control the feedforward circuit to reduce out-of-band frequency component energies in a particular manner. For example, gain and phase of a variable gain-phase network in a feedforward circuit structure can be modified for reducing the out-of-band frequency component energy.

Feedforward amplification system having mask detection compensation

An apparatus and method measure the energy in frequency bands of an amplified signal, the amplified signal being an amplified version of an RF received input signal, where the received signal has an allocated frequency bandwidth and carrier frequency. The carrier frequency, however, is not known in advance of receipt; and therefore, the apparatus and method provide structure and methodology for finding the carrier and then reducing the out-of-band frequency components of the amplified signal. The apparatus features a mixer configured as a four quadrant multiplier biased into a linear operating region. The mixer receives both the received signal and the amplified signal, and produces as its output a baseband signal. Various detection mechanisms can be used to determine the distortion correction control signals based upon the energy in portions of the amplified signal offset from the carrier signal. In a preferred embodiment, the mixer is a Gilbert Cell mixer and the received signal is a CDMA signal.

Amplification system using baseband mixer

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Costa Mesa, CA, United States of America

Sandip Patel