Powerwave Technologies, Inc.

Paradigm Wireless Communications, LLC

Other

Charles R Gentzler

Richard D Posner

Do B Shin

Zvi Y Regev

Bill Vassilakis

Kwang Kim

Sandip Patel

Thinh Dat Do

Gregory French

Thuan Nam Tran

An amplifier arrangement including a main amplifier to which feed-forward cancellation is applied, where the amplifier arrangement comprises an input for receiving signals to be amplified, an output for providing an amplified input signal, a pilot signal modulation circuit to generate a CW frequency shifted pilot signal, a mixer down for converting the pilot signal to an IF signal, and a sampling circuit for digitally sampling the IF signal. The amplifier arrangement includes a signal cancellation loop and a distortion cancellation loop each acting as an independent control function for minimizing pilot signal. The signal cancellation loop utilizes a Cartesian loop method for controlling the signal cancellation loop for sensing both phase and amplitude information simultaneously. The Cartesian loop uses a high frequency active mixer, which is a dual cross coupled differential pairs of devices capable of operating with input signals from near DC to 2.4 GHz, for control of the signal cancellation loop.

Feed-forward amplifier loop control utilizing if signal processing

A switch assembly has a housing and a plurality of controllable switches. The housing has a plurality of input ports and an output port and the plurality of individually controllable switches is arranged within the housing. Each switch has an open position and a closed position and is coupled to one of a plurality of input ports of the housing and a common summing junction within the housing. Each input port receives a coherent radio frequency (RF) signal. The output port is coupled to the common summing junction and outputs a sum signal that includes at least one of the RF signals received at the common summing junction when a switch is in the closed position. The switch assembly may further include impedance matching lines that transform a reference impedance value to a higher value prior to switching and an impedance transformation line that provides for the reference impedance value at a distal end of the impedance transformation line. The impedance transformation lines may be located outside the housing, inside the housing or inside and outside the housing. Further, the switch assembly may include at least one matching stub associated with the output port.

Switch assembly with a multi-pole switch for combining amplified RF signals to a single RF signal

The invention relates to a low cost feed forward RF power amplifier arrangement for amplifying an RF input signal using a main power amplifier operating as a class A/B amplifier. The method and apparatus modify the input signal to the main amplifier to compensate for the distortion added by the main power amplifier. The circuit provides for injecting a delayed version of the input signal, through a fixed gain-phase circuity, at a point whereby the resulting signal is amplified by the error amplifier of the second loop. A digitally controlled processor iteratively modifies various phase and gain controls to adjust the output of the amplifier. Different gain and phase control lines are iteratively updated at different rates.

Low cost, pilotless, feed forward compensation for a power amplifier

This invention relates to the Linearization of multitone or multiple signal amplifiers or like devices. The telecommunications industry is currently employing amplifiers, transmitters or other active devices that are not only amplifying complex digital and analog modulation formats, but are transmitting or amplifying multiple complex signals simultaneously. In order to meet the transmission requirements, amplifiers or transmitters must exhibit extreme phase and amplitude linearity. Deviations from linearity are distortions which lead to intermodulation of the signal components; those intermodulation products appear variously through out the spectrum and cause interference between signals, which in turn degrades the amplified signals. Today the amplification of these signals requires the use of feedforward technology to achieve the performance required to meet government spectrum modulation mask requirements. This invention provides an important advance in the art of extreme phase and amplitude linearity.

Amplifier linearization by learned linear behavior

The invention relates to an amplifier arrangement for amplifying an input using a distorting main power amplifier such as one operating as a class AB amplifier. The method and apparatus add to the input signal to the main amplifier a predistortion signal intended to compensate for the distortion added by the main power amplifier. In accordance with the invention, the input to the predistortion circuit is modified by measuring peak-to-peak signal values of the distortion in the output of the main power amplifier. The peak-to-peak values are measured in a signal derived by comparing an output derived from the main amplifier with an output derived from the input signal. A digitally controlled processor iteratively modifies various phase and gain controls to adjust the output of the amplifier.

Predistortion compensation for a power amplifier

The invention relates to a method and apparatus for reducing the distortion output of an amplifier used with an RF signal. The method and apparatus typically modify the distortion of the amplifier to reduce it, by detecting cross-modulation components modulated onto a continuous wave, low level, pilot signal injected at the input of the amplifier system. The circuitry detects the cross-modulation components and provides correction signals in response thereto.

Amplifier distortion correction using cross-modulation

The invention relates to a low cost feed forward RF power amplifier arrangement for amplifying an RF input signal using a main power amplifier operating as a Class AB amplifier. The method and apparatus modify the input signal to the main amplifier to compensate for the distortion added by the main power amplifier. The circuit provides for injecting a pilot signal prior to the Class AB amplifier and adjusting the correction circuitry of the amplifier based on a quadrature modulated, chopped derivative of the injected pilot signal.

Feed forward compensation using phase and time modulation

A method and apparatus for reducing out-of-band frequency components of an RF signal having a carrier frequency which is not known in advance employ a control signal to vary adjustable bias parameters of the circuit. In particular embodiments, the RF signal is generated from a MOSFET power amplifier, which introduces distortion components into its output signal. Bias parameters of the MOSFET amplifier can be varied to reduce out-of-band frequency components, that is, out-of-band distortion. In addition, other elements of the network can be controlled by varying bias parameters, for example, a predistorter.

Amplification system having mask detection and bias 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

The invention relates to an amplifier arrangement for amplifying an input using a distorting main power amplifier such as one operating as a class AB amplifier. The method and apparatus add to the input signal to the main amplifier a predistortion signal intended to compensate for the distortion added by the main power amplifier. In accordance with the invention, the predistortion signals can be dynamically modified to improve, substantially, at least the third order intermodulation components in the output of the power amplifier. A digitally controlled processor iteratively modifies various phase and gain controls to adjust the output of the amplifier. Different gain and phase control lines are iteratively updated at different rates.

Dynamic predistortion compensation for a power amplifier

The invention relates to an amplifier arrangement for amplifying an input signal using a distorting main power amplifier such as one operating as a class AB amplifier. The amplifier can be biased at different operating points. The method and apparatus modify bias control signals to the main amplifier to reduce or minimize the distortion energy added by the main power amplifier. A digitally controlled processor iteratively modifies various control bias signals to adjust the output of the amplifier. Different gain and phase control lines can also be iteratively updated at different rates.

Adaptive biasing in a power amplifier

A broadband feed-forward amplifier configuration includes an amplifier having an input and an output. A comparison loop compares the signal output to the amplifier with a signal input to the amplifier to generate an error signal and this error signal is inverted, processed, and amplified to provide a correction signal at the output of the amplifier (the cancellation loop). In the cancellation loop and at the input of the main amplifier, the circuit includes gain and phase correction circuitry for correcting small variations in amplitude and phase. A quadrature modulated pilot signal is injected at the input to the main amplifier path and is cancelled in the output to generate control signals for controlling the gain and phase correction circuits within the cancellation loop and within the main amplification loop.

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Thousand Oaks, CA, United States of America

Charles R Gentzler