The Aerospace Corporation

Christopher Joseph Clark

Robert Bernhard Dybdal

Christopher Patrick Silva

Andrew Alfred Moulthrop

Michael Steven Muha

Lan Xu

Samuel Joseph Curry

Fei Wang

Don J Hinshilwood

Flavio Lorenzelli

A system is provided with circuits and methods for dynamically reducing interference to maintain linear system operation and mitigate interference degradation to desired signal components. The system can include a binning subcircuit system configured to divide the digitized input signal into a plurality of spectral bins each having a power level. A power analysis subcircuit can be coupled to the binning subcircuit and configured to compare a collective power level of spectral bins to a threshold level that would produce nonlinear system operation. Based upon the collective power level exceeding the threshold level, outputting a gain control signal to a variable gain amplifier so that the system remains linear. This dynamic gain control can be applied to systems that receive and/or transmit signals. Residual interference components that degrade signal components can be dynamically removed by excision and the distortion introduced by the excision process can be reduced with equalization circuitry.

Circuits and methods for reducing interference that spectrally overlaps a desired signal based on dynamic gain control and/or equalization

Under one aspect, a system includes circuitry that digitizes and Fourier transforms first and second beams and outputs first and second sets of spectral bins. Each bin may include a portion of a group of signals or interference. The circuitry compares the collective power levels of each set of spectral bins to a predetermined threshold, and excises at least one bin of that set that contains the interference if the collective power level of that set exceeds the predetermined threshold. The circuitry determines an angular location of the interference based on excised bins, combines remaining bins with weights selected to form a null in a pattern of the first and second beams that is aligned with the interference's angular location, and inversely Fourier transforms the combined remaining bins and outputs the group of signals less any interference that was excised or excluded by the null.

Systems and methods for reducing narrow bandwidth and directional interference contained in broad bandwidth signals

A dynamic equalization system and method for use with a receiver is provided. The receiver may include an antenna for receiving a signal having multipath signal components and a digitizer for obtaining and digitizing the received signal and multipath signal components. The digitized signal segment and multipath signal components may be discretized into signal segments of length n. Channel parameters of each of the discrete signal segments may be analyzed and locked to, and a time-domain representation of the analyzed channel parameters may be output. Each time-domain representation may be Fourier transformed into a frequency-domain representation, based upon which equalization parameters to equalize the multipath signal components for each of the analyzed channel parameters may be determined. The equalization parameters may be applied to corresponding signal segments of the digitized signal and multipath signal components so as to equalize the multipath signal components.

Dynamic equalization systems and methods for use with a receiver for a multipath channel

Under one aspect of the present invention, a system for processing a group of signals and interference includes (a) an analog-to-digital (A/D) converter for digitizing the group of signals and the interference; (b) a Fourier transform circuit for obtaining a Fourier transform of the digitized group of signals and the interference and to provide as output spectral bins, at least one of which contains the interference; (c) a power analysis circuit for comparing the collective power level of the spectral bins to a predetermined threshold, and if the collective power level exceeds the predetermined threshold, and for excising at least one bin that contains the interference; and (d) an inverse Fourier transform circuit for obtaining an inverse Fourier transform of the remaining spectral bins and outputting a digitized group of signals less the interference in any excised spectral bin.

Systems and methods for reducing narrow bandwidth interference contained in broad bandwidth signals

A time-domain baseband measurement method measures modulated microwave signals typically used in communication systems by converting microwave signals to baseband before measurement for improved accuracy compared to direct measurement at the microwave frequency. A downconverting receiver is first characterized using a prior characterization method and then the modulated microwave signal is applied to the downconverting receiver and the response of the downconverting receiver is removed to provide an accurate characterization of the modulated microwave signal. Such an accurate measurement of the modulated microwave signal can be used for communications system performance verification as well as for characterizing communications devices and systems. One particular application is the measurement of input/output characteristics of nonlinear power amplifiers using such modulated microwave signals.

Baseband time-domain waveform measurement method

A three-pair measurement method determines the amplitude and phase transmission response of frequency translating devices including a device under test and two test devices using a vector network analyzer and a controller where one of the devices has reciprocal frequency response characteristics. The characterization of single sideband and double sideband devices such as mixers, is preferably performed by combining data from analyzer two-port swept measurements. The measurement method provides a low-pass equivalent transmission response of the devices.

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Hermosa Beach, CA, United States of America

Christopher Joseph Clark