Abstract: Systems and method are provided for making a balun's operational bandwidth tunable around multiple distinct center frequencies by using switches to vary the balun's dimensions. An embodiment of the present disclosure uses a pass gate structure for the switches, and the switches connect additional lengths of line in or out of the balun to change its frequency response. A balun in accordance with an embodiment of the present disclosure is able to switch its response between 2 or more adjacent bands by switching additional length of lines in and out of the balun's core windings.

Abstract: A Frequency Position Modulation system for encoding signals for transmission. A signal's discrete frequency support is used to represent symbols. The signal can be non-uniformly spread over many GHz of instantaneous bandwidth, resulting in a communications system that is resilient to interference and difficult to intercept. The FPM symbols are recovered using adaptive projections that use an analog polynomial nonlinearity paired with an analog-to-digital converter that is sampling at a rate at that is only a fraction of the instantaneous bandwidth of the signal. In the presence of partial band interference, nonlinearities generated by the transmitter are exploited by the receiver to help unambiguously recover tones that could otherwise be lost. The nonlinearities are generated by driving the power amplifier of the transmitter into saturation to induce distortions at a desired level.

Abstract: Systems and method are provided for making a balun's operational bandwidth tunable around multiple distinct center frequencies by using switches to vary the balun's dimensions. An embodiment of the present disclosure uses a pass gate structure for the switches, and the switches connect additional lengths of line in or out of the balun to change its frequency response. A balun in accordance with an embodiment of the present disclosure is able to switch its response between 2 or more adjacent bands by switching additional length of lines in and out of the balun's core windings.

Abstract: A Frequency Position Modulation system for encoding signals for transmission. A signal's discrete frequency support is used to represent symbols. The signal can be non-uniformly spread over many GHz of instantaneous bandwidth, resulting in a communications system that is resilient to interference and difficult to intercept. The FPM symbols are recovered using adaptive projections that use an analog polynomial nonlinearity paired with an analog-to-digital converter that is sampling at a rate at that is only a fraction of the instantaneous bandwidth of the signal. In the presence of partial band interference, nonlinearities generated by the transmitter of are exploited by the receiver to help unambiguously recover tones that could otherwise be lost. The nonlinearities are generated by driving the power amplifier of the transmitter into saturation to induce distortions at a desired level.

Abstract: A Frequency Position Modulation system for encoding signals for transmission. A signal's discrete frequency support is used to represent symbols. The signal can be non-uniformly spread over many GHz of instantaneous bandwidth, resulting in a communications system that is resilient to interference and difficult to intercept. The FPM symbols are recovered using adaptive projections that use an analog polynomial nonlinearity paired with an analog-to-digital converter that is sampling at a rate at that is only a fraction of the instantaneous bandwidth of the signal. In the presence of partial band interference, nonlinearities generated by the transmitter of are exploited by the receiver to help unambiguously recover tones that could otherwise be lost. The nonlinearities are generated by driving the power amplifier of the transmitter into saturation to induce distortions at a desired level.

Abstract: A Frequency Position Modulation system for encoding signals for transmission. A signal's discrete frequency support is used to represent symbols. The signal can be non-uniformly spread over many GHz of instantaneous bandwidth, resulting in a communications system that is resilient to interference and difficult to intercept. The FPM symbols are recovered using adaptive projections that use an analog polynomial nonlinearity paired with an analog-to-digital converter that is sampling at a rate at that is only a fraction of the instantaneous bandwidth of the signal. In the presence of partial band interference, nonlinearities generated by the transmitter of are exploited by the receiver to help unambiguously recover tones that could otherwise be lost. The nonlinearities are generated by driving the power amplifier of the transmitter into saturation to induce distortions at a desired level.

Abstract: Complex polyphase nonlinear equalizer (cpNLEQs) mitigate nonlinear distortions generated by complex in-phase/quadrature (I/Q) time-interleaved analog-to-digital converters (TIADCs). Example cpNLEQs upsample the digital waveform emitted by the TIADC, e.g., by a factor of two, then separate the upsampled digital waveform into upsampled in-phase and quadrature components. Processors in the cpNLEQs create real and imaginary nonlinear compensation terms from the upsampled in-phase and quadrature components. The nonlinear compensation terms are downsampled, and the downsampled imaginary nonlinear compensation term is phase-shifted, then combined with the downsampled real component to produce an estimated residual distortion. Subtracting the estimated residual distortion from the digital waveform emitted by the TIADC yields an equalized digital waveform suitable for further processing.

Abstract: Polyphase nonlinear digital predistorters (pNDPs) mitigate nonlinear distortions generated by time-interleaved digital-to-analog converters (TIDACs). Processors in an example pNDP compute nonlinear and linear compensation terms representative of channel mismatches and other imperfections in the TIDAC based on the digital input to the TIDAC. The pNDP subtracts these compensation terms from a delayed copy of the digital input to yield a predistorted digital input. The TIDAC converts on the predistorted digital input into a fullband analog output that is substantially free of nonlinear distortion.

Abstract: Polyphase nonlinear digital predistorters (pNDPs) mitigate nonlinear distortions generated by time-interleaved digital-to-analog converters (TIDACs). Processors in an example pNDP compute nonlinear and linear compensation terms representative of channel mismatches and other imperfections in the TIDAC based on the digital input to the TIDAC. The pNDP subtracts these compensation terms from a delayed copy of the digital input to yield a predistorted digital input. The TIDAC converts on the predistorted digital input into a fullband analog output that is substantially free of nonlinear distortion.

Abstract: Complex polyphase nonlinear equalizer (cpNLEQs) mitigate nonlinear distortions generated by complex in-phase/quadrature (I/Q) time-interleaved analog-to-digital converters (TIADCs). Example cpNLEQs upsample the digital waveform emitted by the TIADC, e.g., by a factor of two, then separate the upsampled digital waveform into upsampled in-phase and quadrature components. Processors in the cpNLEQs create real and imaginary nonlinear compensation terms from the upsampled in-phase and quadrature components. The nonlinear compensation terms are downsampled, and the downsampled imaginary nonlinear compensation term is phase-shifted, then combined with the downsampled real component to produce an estimated residual distortion. Subtracting the estimated residual distortion from the digital waveform emitted by the TIADC yields an equalized digital waveform suitable for further processing.

Abstract: A method or corresponding apparatus relates to a mathematical approach to efficiently search for and localize regions in a multi-dimensional signal space to enable inversion of power amplifier nonlinearities with a significant reduction in computational complexity and an efficient hardware implementation. To linearize a wideband power amplifier, an example embodiment of the present invention may represent a response of the wideband power amplifier using coefficients in a cube coefficient subspace, and search over the full multi-dimensional subspace according to an optimization criterion in order to identify a vector of cube coefficient subspace coefficients. The vector of coefficient subspace coefficients may be used to linearize the wide-band power amplifier.

Abstract: A method or corresponding apparatus relates to a mathematical approach to efficiently search for and localize regions in a multi-dimensional signal space to enable inversion of power amplifier nonlinearities with a significant reduction in computational complexity and an efficient hardware implementation. To linearize a wideband power amplifier, an example embodiment of the present invention may represent a response of the wideband power amplifier using coefficients in a cube coefficient subspace, and search over the full multi-dimensional subspace according to an optimization criterion in order to identify a vector of cube coefficient subspace coefficients. The vector of coefficient subspace coefficients may be used to linearize the wide-band power amplifier.