Andrew Corporation

Blue Danube Systems, Inc.

Lucent Technologies Inc.

At&t Bell Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

Josef Ocenasek

Christopher F Zappala

William A Nitz

James Emerick

Robert M Honeycutt

Robert Charles Frye

George Philip Vella-Coleiro

Peter Kiss

John Stanley Rucki

Richard J Lisco

Bernard J Arntz

James C Giacobazzi

Michael Eugene Burke

Jeffrey G Strahler

Jeffrey A Siegel

A removable module for a phased array, the module including: a circuit board having a ground plane formed on one side of the circuit board; an antenna mounted on and extending away from a topside of the circuit board; circuitry on a backside of the circuit board, the circuitry including an RF front end circuit coupled to the antenna; and a group of one or more first connecters mounted on the backside of the circuit board, the first connectors for physically and electrically connecting and disconnecting the module from a master board through a corresponding group of one or more matching second connectors on the master board, the first connectors on the module having electrically conductive lines for carrying an externally supplied LO signal for the RF front end circuit and an IF signal for or from the RF front end circuit.

Modular phased array

An antenna system including: a metal base plate; an antenna element arranged on and extending away from the front side of the base plate; a circuit board including a ground plane, adjacent to, and in thermal contact with the base plate; a plurality of electrical components on the circuit board including a power amplifier and an I/O connector; a metal support plate separated from, parallel to, and facing the base plate, with the circuit board located between the base and support plates; a plurality of thermally conductive standoffs thermally connecting the base plate to the support plate; and a master board including an I/O connector mating with the I/O connector on the circuit board and electrically connecting the circuit board to the master board, the master board located between the circuit board and the support plate and including signal paths for routing signals to the circuit board.

Low thermal impedance structure in a phased array

In one embodiment, an amplifier system has a tap, a delay filter, a linearized amplifier, and a hybrid combiner. The tapped portion of an input signal is amplified by the amplifier, the untapped portion of the input signal is delayed by the delay filter, and the combiner combines the resulting amplified, tapped portion and the delayed, untapped portion to generate an amplified output signal. By re-combining the delayed, untapped portion of the input signal with the amplified, tapped portion, the power of the untapped portion is not lost, and the amplifier does not have to compensate for all of the distortion that would otherwise be associated with the total output power level. Such an amplifier system is applicable, for example, in upgrading an existing GSM cell site to support both GSM communications as well as UMTS communications without degrading GSM operations.

Amplifier system for cell sites and other suitable applications

In an amplifier system that linearizes an amplifier by pre-distorting the input signal prior to amplification, a baseband pre-distortion processor processes the input signal in a digital baseband domain to generate one or more pre-distortion parameters based on the power of the digital baseband input signal. The digital baseband signal is up-converted and D/A-converted into a non-baseband (e.g., IF or RF) signal which is then pre-distorted, e.g., using a phase/gain adjuster or a vector modulator. By generating the pre-distortion parameters at baseband, while pre-distorting the input signal at non-baseband, the amplifier system avoids the cost and inaccuracies associated with analog signal delay and RF power detection of prior-art 'all-RF' pre-distortion implementations, while avoiding the wider-bandwidth filtering of prior-art 'all-baseband' pre-distortion implementations.

Linearization of amplifiers using baseband detection and non-baseband pre-distortion

Two or more digital-input RF amplifiers are configured in parallel such that a combiner combines their respective outputs to generate a relatively large composite RF output signal. A feedback control architecture minimizes the phase differences between the various amplifier outputs so that the outputs can be efficiently combined. The feedback control can measure the return loss for each amplifier to determine how to adjust each amplifier's phase. In some embodiments, the feedback control can also measure the composite RF output signal for use in phase adjustment. In certain implementations, phase adjustment is implemented by an iterative coarse phase-adjustment mode (e.g., based on either the return loss or the composite output signal) followed by an iterative fine phase-adjustment mode (e.g., based on the return loss).

Paralleling digital-input amplifiers

In an amplifier system having two or more different amplifier sub-systems, the input signal to at least one of the amplifier sub-systems is pre-distorted based on the combined output signal from the two or more amplifier sub-systems. In one embodiment, each other amplifier sub-system pre-distorts its input signal based on only its own output signal. In one operational scenario, during initial operations, each amplifier sub-system separately pre-distorts its input signal based on only its own output signal. After pre-distortion has settled, one of the amplifier sub-systems is switched to pre-distort its input signal based on the combined output signal, while the other amplifier sub-systems continue to pre-distort their input single based on only their own output signals.

Pre-distortion cross-cancellation for linearizing power amplifiers

An amplifier distortion reduction system detects a plurality of amplitudes corresponding in time within a frequency band of operation. In response to at least one of the plurality of amplitudes, adjustments can be made to components within the frequency band of operation, enabling the amplifier distortion reduction system to adapt to changing operating conditions. In a feed forward embodiment having a carrier cancellation loop and IMD cancellation or distortion cancellation loop, the output of the carrier cancellation loop can be monitored and equalizer adjustments provided to reduce the amplitude of the carrier signal(s) equally over the frequency band of operation. The output of the IMD cancellation loop can be monitored and equalizer adjustments provided to reduce the IMD components equally over the frequency band of operation. Thus, processing circuitry can monitor amplitudes corresponding in time over the frequency band of operation and provide improved performance over the frequency band.

System and method for producing an amplified signal using plurality of amplitudes across spectrum

A predistortion system uses a pilot signal to determine a predistortion function which is used to produce amplitude and/or phase adjustment(s) of an input signal on a signal path. Rather than simply detecting the input signal envelope before and after distortion generating circuitry, such as an amplifier, a pilot signal is provided on the signal path prior to the distortion generating circuitry. After the distortion generating circuitry, the pilot signal is detected. The predistortion system can determine the predistortion function by using the generated pilot signal and the detected pilot signal, for example, to provide improved characterization of the amplifier amplitude and/or phase response or to directly improve the determination of the predistortion function. In certain embodiments, the predistortion function is implemented using a look-up table to produce the amplitude and/or phase adjustment values, and the pilot signal is produced on the signal path by adding the pilot signal to the amplitude and/or phase adjustment values of the look-up table.

Predistortion system and method using a pilot signal

Therefore a method and apparatus for controlling a linear amplifier processing a plurality of carrier signals of a multi channel carrier system alters the phases of one or more sources of the multi-channel signals in response to a detected peak envelope power or of a peak to average power ratio at regular scheduled intervals. This reduces the peak envelope power to average envelope power ratio and enables the reduction in the power rating required by the amplifiers handling the multi-channel signal.

Method and apparatus for reducing the peak-to-average power in

The power output from a laser transmitter is maintained within predetermined levels. These levels are maintained at fixed percentages on either side of the average laser output power which is transmitted, regardless of variations in ambient temperature. This is achieved by coupling the bias current control loop to the modulation current control circuit.

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Whippany, NJ, United States of America

Josef Ocenasek