Itt Manufacturing Enterprises, Inc.

Stephen P Stoyanov

Gene L Cangiani

Paul A Gilmour

A communication system generates a constant-envelope composite signal containing at least two signals whose power levels, bandwidths, and/or data rates are independently controllable. Binary offset carrier (BOC) modulation is applied to the signals to be combined in the composite signal. The BOC modulated signals are then combined via interplex modulation to form a constant-envelope composite signal in which the constituent signals modulate different offset carriers. For example, real BOC modulation can be used to generate a ranging signal in edge portions of the transmission band of the composite signal, while complex BOC modulation can be used to generate a frequency agile data signal in a center portion of the transmission band. Such a signal can be used for full duplex communications in satellite crosslinks. The interplex modulation allows independent control of the power levels of the two signals while maintaining a constant envelope, permitting use of saturated RF amplifiers.

System for generating constant envelope simultaneous data and ranging waveform with anti-jam properties

A technique for combining a plurality of signals to form a multi-carrier constant-envelope composite signal includes generating a constant-amplitude inphase (I) composite signal based on a majority vote of a first set of signals and generating a constant-amplitude quadrature (Q) composite signal based on a separate majority vote of a second set of signals. The I and Q components of a carrier signal are respectively modulated with the I and Q composite signals and combined to form the constant-envelope composite signal. In the case where a single offset carrier code is a constituent of the constant-envelope composite signal, a scale factor is applied to one of the I and Q composite signals to equalize the power of the I and Q components of the offset carrier code.

Multi-carrier constant envelope signal scheme for power and bandwidth efficient communications

A signal synthesizer according to the present invention produces a high speed or high frequency carrier waveform without employing an ASIC or FPGA operating at a sampling rate of greater than twice the carrier frequency. The signal synthesizer basically simulates a high speed or high frequency direct digital synthesizer with a plurality of low speed or low frequency direct digital synthesizers. The low speed synthesizers are operated in parallel and each one produces an intermediate carrier waveform with a frequency less than the desired carrier frequency. The intermediate carrier waveforms are subsequently multiplexed together to form a high frequency digital carrier waveform that is subsequently converted to an analog signal with a high-speed digital-to-analog converter. In addition, the signal synthesizer may perform phase, frequency and/or amplitude modulation.

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Clifton, NJ, United States of America

Stephen P Stoyanov