Northrop Grumman Systems Corporation

Northrop Grumman Corpoation

Ian Robinson

Frank B Winter

Jeffrey Mark Hinrichs

Kenneth Weber

Jasmine Upendra Patel

Paul Charles MacFalda

William Marvin Skones

Frederic Joel Harris

Reza Dehmohseni

Jack Macek

Walter DeMore

A communication system and method is provided that modifies a signal for transmission at a transmitter to reduce peaks associated with the signal. The signal can be modified employing signal shaping, signal clipping, signal decomposition or other techniques to remove peaks associated with the signal. The communication system can also correct the modified signal at a receiver to reconstruct the originally wanted signal.

Communication system and method for improving efficiency and linearity

An assembly and method for processing of multi-carrier signals is provided. A plurality of carrier signals are combined into a combined multi-carrier signal represented in a first domain. The combined multi-carrier signal is converted from the first domain to a second domain. The converted multi-carrier signal is distributed into a plurality of signals represented in the second domain.

Multi-carrier transceiver assembly

Systems and methods for signal conversion are provided. Signals are spread in a continuous spectrum by a spread spectrum signal, such as a direct sequence spread spectrum (DS-SS) signal. The signals are then processed, which may include but is not limited to analog-to-digital conversion, digital-to-analog conversion, frequency conversion, clipping, filtering or a plurality of processes. The processed signal is then despread using substantially the same spreading signal that was used to spread the signal.

Systems and methods for signal conversion

Soft handover of a mobile unit is facilitated on a wireless network from base station to base station. The network can employ multi-channel receivers to receive signals from mobile units within range, including mobile units assigned to neighboring base stations. Information associated with received signals, such as an indication of their signal strength, can be relayed to a central location for assessing whether the mobile unit should be assigned to another base station, and implement reassignment of one or more mobile units based on such assessment. Soft handover reduces dropped calls when the connection from mobile to base station is unexpectedly lost. The second BTS can add a carrier to communicate with the mobile unit and provides the mobile unit with the necessary parameters, such as frequency and time slot data, to complete the handover or the connection can be established through a variety of contingency plans.

Method and system for soft handover

Signal conversion is implemented employing a memory system operating as a look-up table that stores a plurality of sets of output samples associated with each of a plurality of respective input samples. The look-up table thus can generate a corresponding set of output samples in response to a given input sample, thereby emulating desired digital upsampling and delta-sigma modulation. The output samples can be aggregated, such as by multiplexing, to provide an output data stream at a desired sample rate.

Look-up table delta-sigma conversion

Systems and methods are provided for providing high dynamic range operation over a variable range of frequencies. A delta-sigma modulator, having associated frequency characteristics, produces a digital output signal. A digital-to-analog converter converts the digital output signal into an analog signal. A clock circuit provides a clock signal to the delta-sigma modulator and the digital-to-analog converter. A frequency control controls one or more of the clock circuit, the delta-sigma modulator, and the digital-to-analog converter to alter the frequency characteristics of the delta-sigma modulator. A filter circuit can provide one or more passbands to one or more downstream amplifiers ensuring that out of band quantization noise is removed before amplification.

Frequency agile exciter

An amplification system and method is provided that employs a digital cross-cancellation technique which provides a separate digital signal to be input to a separate DAC to generate a cancellation signal. The cancellation signal is added to the output of the amplifier to produce a final signal with substantially reduced distortion and/or out-of-band emissions. The cancellation signal can be pre-computed or derived by generating an inverted version of the wanted signal, and combining it with a portion of the output signal to determine the error or unwanted portion of the output signal. This error signal is then combined with a delayed version of the output signal.

Digital cross cancellation system

Frequency synthesis is implemented by providing a delta-sigma modulated signal associated with a selected frequency, which frequency can vary based on a selection input. The delta-sigma modulated signal is converted from the digital to analog domain. The delta-sigma modulated signal can be provided directly from memory based on the selection input or, alternatively, it can be provided by a signal generator and processed by a delta-sigma modulator to provide the delta-sigma modulated signal. The selected frequency can be varied at a high rate of speed.

Digital frequency synthesis

An amplification system and method is provided that reduces peaks associated with an input signal, and provides correction, in one or more spectral bands, to signal distortion and out-of-band emissions that result from the peak reduction. The correction signal that removes signal distortion and OOB emissions associated with the peak reduction can be calculated or electronically derived. The correction signal can be combined with the peak reduced signal prior to or after amplification of the peak reduced input signal.

System and method for reducing dynamic range and improving linearity in an amplication system

An amplifier system is provided that switches between a linear mode of operation, an envelope tracking mode of operation and a polar mode of operation. The amplifier system switches between modes of operation based upon a characteristic of an input signal relative to a first threshold level and a second threshold level. A mode selector selects the operation mode by transmitting an amplitude modulated signal plus a variable headroom voltage to a supply terminal of a power amplifier during the envelope tracking mode, an amplitude modulated signal to the supply terminal and phase modulated input signal during the polar mode and a substantially constant amplitude signal to the supply terminal during the linear mode.

Multi-mode amplifier system

An amplification system and method is provided that reduces peaks associated with an input signal, and provides correction, in one or more spectral bands, to signal distortion and out-of-band emissions that result from the peak reduction. The correction signal that removes signal distortion and OOB emissions associated with the peak reduction can be calculated or electronically derived. The correction signal can be combinded with the peak reduced signal prior to or after amplification of the peak reduced input signal.

An amplifier system is provided that switches between operation in a polar mode and a signal restoration mode based on a characteristic of an input signal relative to a threshold level. The system includes a correction path that mitigates distortion and out-of-band (OOB) emissions in the polar mode and provides at least a substantial portion of the amplified output signal in the signal restoration.

Modified polar amplifier architecture

Systems and methods are provided for determining and providing an appropriate variable voltage supply to a power amplifier. A power amplifier is operative to amplify an input signal. A digital buffer stores a copy of the input signal representing a predetermined interval of time. An envelope profiler analyzes the buffered interval of the input signal and determines an appropriate supply signal profile for the power amplifier over the predetermined time interval. A supply control provides a supply signal according to the determined profile.

Variable supply amplifier system

An amplifier system for amplifying an input signal comprises first and second polar amplifier assemblies and a mode selector. The first polar amplifier assembly is operative to amplify the input signal to produce an amplified output signal for the system when the system is in a first mode. The second polar amplifier assembly is operative to amplify the input signal to produce the amplified output signal for the system when the system is in a second mode. A mode selector selects a mode of operation from at least the first and second modes for the amplifier system according to at least one characteristic of the input signal relative to at least one threshold parameter.

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Venice, CA, United States of America

Ian Robinson