Andrew Corporation

Robert W Kooker

Paul E White

Thomas A Bachman, Ii

Paul S Everline

Robert Snyder

Leonard Sarver

David M January

Philip Shenenberger

A feed forward power amplifier system and method identify active channels across a frequency band to suppress unwanted intermodulation distortion (IMD) products in a communications signal such as a single- or multi-carrier communications signal. A scanning receiver identifies at least one active channel in a frequency band, and identifies at least one portion of the frequency band likely to include IMD products based upon the identified active channel(s). Based upon the identified portion of the frequency band, IMD products are suppressed from the communications signal, e.g., by controlling the magnitude and/or phase of a suppression signal mixed with the communications signal.

Scanning receiver for use in power amplifier linearization

A power feedforward amplifier uses integral cavities to provide RF isolation between subcircuits of the power amplifier. The chassis includes a main chassis body and a lid structure adapted to couple with the chassis body and define the subcircuit cavities. The inner lid includes an amplifier dividing wall and interstage walls adapted to isolate the main and error amplifier subcircuits of the feedforward power amplifier and further to isolate individual components of the subcircuits. In one embodiment, the amplifier subcircuits are mounted on a single circuit board and isolated from each other by the dividing wall. A delay line subcircuit portion is integral with the main chassis body and is coupled beneath the error amplifier subcircuit to contain and electromagnetically shield a delay line filter subcircuit while providing direct connection with the error amplifier.

Compact, high efficiency, high isolation power amplifier

A power amplifier system and method for locating carrier frequencies across a frequency band, identifying the modulation format of each carrier, and locating and suppressing undesired intermodulation distortion (IMD) products generated by the power amplifier. The system includes an amplifier for amplifying RF carrier signals in a main signal path, a variable phase shifter and variable attenuator on a feed forward path, and a tunable receiver that digitizes a portion of the frequency band to baseband. The tunable receiver includes a tunable voltage controlled oscillator which provides an oscillating frequency to a mixer and is phase-locked to a highly stable reference oscillator. The mixer downconverts a desired RF based on the oscillating frequency to IF. A filter passes only a selected portion of the IF signals, and the filter has a passband sufficient to discern both narrowband and wideband carriers and their associated IMD products. Based on the locations of the carrier frequencies, a processing unit determines the IMD locations of the carrier frequencies, determines the IMD locations, and adjusts the variable phase shifter and variable attenuator on the feed forward path until the IMD products in the main signal path are suppressed below a desired threshold.

Digital baseband receiver in a multi-carrier power amplifier

The present invention provides a power amplifier system in which one or more power amplifiers may be inserted. The occupancy of ports by power amplifiers is monitored by a controller. The system has a plurality of output lines, each with different electrical line characteristics. The controller is responsive to ports becoming occupied or unoccupied by power amplifiers and routes the output signal through the output line having the electrical line characteristics that ensure an efficient signal transfer. Further, the switching configuration of the present invention eliminates the need for output signals to traverse through a switch.

Growing community of inventors

Freeland, MD, United States of America

Robert W Kooker