Soma Networks, Inc.

Lucent Technologies Inc.

At+t Corp.

At&t Bell Laboratories

Wi-lan Inc.

Caci, Inc. - Federal

James Russell Blodgett

Michael W Goodwin

Robert B Ward

Fred J Heinzman

Harold Allan Simpson

Fred Judson Heinzmann

James P Moffatt

Gerald L Frazer

Karen E Leonard

Bruce R Bouchard

Fan Zhang

This application is generally related to methods and systems for improving amplifier performance. For example, the system includes two or more gain and phase modulators. The system also includes two or more component amplifiers operably coupled to, and downstream of, the power splitter, where each of the two or more component amplifiers is operably coupled to a respective one of the two or more gain and phase modulators. The system further includes a power combiner operably coupled to, and downstream of, the two or more component amplifiers, configured to output a power signal. The system even further includes a Walsh generator configured to generate and transmit first and second Walsh codes to each of the two or more gain and phase modulators. The first Walsh code is orthogonal to the second Walsh code. A first set of the first and second Walsh codes is inverted with respect to a second set of the first and second Walsh codes.

Method and apparatus for achieving and maintaining balance in solid-state RF and microwave power amplifiers

A wireless local loop system is provided that includes a wireless base station that communicates with a subscriber station via a wireless link. The wireless link can carry a voice service, such as telephone calls, or a data service, such as internet browsing. The subscriber station includes a steerable antenna. A presently preferred steerable antenna for use with the subscriber station includes a driven element mounted on a base plane that is surrounded by a plurality of parasitic elements also mounted to the base plane. The parasitic elements can be optionally grounded or floated in order to reflect the wireless link towards the driven element. The antenna can be oriented in a desired direction during the transception of a voice or data service. A method of transceiving between a wireless local loop subscriber station and a wireless local loop base station is also provided.

Wireless local loop antenna

A feed-forward amplifier having a signal cancellation loop including a cancellation node that includes a gain controller and a phase controller. Each controller provides a discrete tap steering signal and modulates the corresponding tap steering signal with a discrete tracer signal that takes on a preselected sequence of values. The sequence chosen so that the tracer signal is mutually orthogonal to each other tracer signal over a preselected period. A gain and phase adjuster connected to the outputs of the controllers provides a controlled gain change and phase shift in the signal cancellation loop, the magnitude of the gain change and phase shift controlled by the corresponding tap steering signals presented to the gain and phase adjuster by the controllers. A detector, the input of which is connected to the cancellation node and the output of which is connected to the controllers, outputs a measure of the envelope of the signal at the cancellation node. After the preselected period new values for the tap steering signals presented to the gain and phase adjuster by the controllers are obtained by multiplying detector output by the respective tracer signal, each over the respective preselected period, summing each resulting series of values, and changing the tap steering signals to be modulated and presented to the gain and phase adjuster in accordance with the values of the respective sums.

Method and apparatus for controlling adaptive circuits

An apparatus and method for providing an electrically adjustable RF delay in which a splitter splits an input signal into two signal paths, one signal path providing a delay fixed at an integral number of wavelengths of a desired center frequency and both signal paths providing electrically adjustable attenuation. A combiner combines the signals passing through the signal paths, such that the sum of the electrically-adjustable attenuation provided by the signal paths adds to unity, whereby the input signal is delayed by an adjustable time depending upon the attenuations provided by the signal paths.

Method and apparatus for electrically adjusting delay in radio-frequency systems

An apparatus and method for operating a feed-forward amplifier in which, after the signal-cancellation and intermodulation-cancellation loops have initially been nulled, the feed-forward amplifier is operated so that both loops are controlled so as to minimize intermodulation at the output of the feed-forward amplifier.

Apparatus and method for controlling feed-forward amplifiers

Apparatus and method for controlling adaptive circuits

The present invention provides a novel feed forward amplifier ('FFA') and a pilot tone generator-receiver therefor. In an embodiment of the invention, the feed forward amplifier only requires a single oscillator to operate both the pilot tone generator and pilot tone receiver used in conjunction with the amplifier circuitry of the FFA. In another embodiment of the invention, a method is provided of generating and detecting a pilot tone from a single oscillating signal.

Feed forward amplifier

An adaptive controller generates a sequence of dither signals for each of a plurality of control parameters. Each dither signal sequence is uncorrelated with every other dither signal sequence. Each nominal control signal has the first of its respective dither signal values simultaneously summed with it to form the control parameter values used by the controller. Updated control signals are applied in parallel to the controller outputs and a performance measure is taken and stored. The second signals in the dither control sequences are then summed with their respective nominal controls and applied in parallel to the controller and a second performance measure is taken and stored. This process is repeated for the length of the dither control signal sequence to yield a sequence of performance measurements. The sequence of performance measurements is correlated with each of the dither sequences, forming sequences of correlator outputs, one for each control signal. Each correlator output sequence is integrated and, depending upon the value of a correlator's integration output, the corresponding nominal signal has it's dither value added to or subtracted from it to form the respective, updated control values.

Apparatus and method for adaptive control

An apparatus and method for operating an adaptive circuit includes injecting a set of orthogonal tracer signals into the circuit. The tracers signals are extracted after modification by at least a portion of the circuit and are examined by respective controllers to modify operation of the circuit. In one embodiment, the invention is incorporated into a feed forward amplifier where a set of orthogonal tracer signals are injected into the amplifier. A detector controller detects the orthogonal tracer signals, as modified by portions of the amplifier, and applies each tracer signal to a respective controller. Each controller examines its respective signal and modifies its output to control a portion of the amplifier accordingly. The controllers apply their outputs to the respective portions of the amplifier at substantially the same time, leading to quick convergence of the operating point of the amplifier to an optimal or near-optimal configuration. Injection of the tracer signals into the amplifier is accomplished by dithering the controller outputs by the respective orthogonal tracer signals.

The present invention provides a novel feed forward amplifier (&ldquo;FFA&rdquo;) and a pilot tone generator-receiver therefor. In an embodiment of the invention, the feed forward amplifier only requires a single oscillator to operate both the pilot tone generator and pilot tone receiver used in conjunction with the amplifier circuitry of the FFA. In another embodiment of the invention, a method is provided of generating and detecting a pilot tone from a single oscillating signal.

An amplifier system includes an input circuit loop and an output circuit loop coupled to a balanced amplifier assembly. The balanced amplifier assembly provides both a nonlinear distortion signal component and a corrective precursor signal component for enhanced and virtually complete cancellation of the nonlinear distortion signal component. A phase shifter facilitates phase shifting in a feedback signal path between the output circuit loop and the input circuit loop to form a corrective signal component from the corrective precursor signal.

Amplifier having linear characteristics

A method for linearizing amplifiers by measuring the intermodulation products at the output of the linearized amplifier using minimum additional hardware without the performance problems associated with pilot tones. In one embodiment, the amplifiers are adaptively linearized using performance monitoring radios. Specifically, the performance monitoring radios are used to measure the signal levels of the intermodulation products in unused communication channels. Such measurements are then used to adaptively linearize the amplifiers and reduce the levels of intermodulation products.

Growing community of inventors

Walnut Creek, CA, United States of America

James Russell Blodgett