Abstract: Nyquist folding receivers (NYFRs) are disclosed that use three or more non-modulated sampling clock signals with different frequencies to produce multiple projections in a sampled output. Using these three or more different sampling clock signals, multiple Nyquist zones are aliased together while still allowing signals from different Nyquist zones to be separated and identified in later processing based upon the sampling provided by the different sampling clock signals. NYFR sampling receivers are also disclosed that simultaneously produce multiple separate and different parallel channels from an input signal, with each different channel having a different sampling clock sampling rate from the other channels so as to generate a respective folding pattern that is different from the folding pattern generated by the respective RF sampling rate of each of the other simultaneous and parallel channels.

Abstract: Nyquist folding receivers (NYFRs) are disclosed that use three or more non-modulated sampling clock signals with different frequencies to produce multiple projections in a sampled output. Using these three or more different sampling clock signals, multiple Nyquist zones are aliased together while still allowing signals from different Nyquist zones to be separated and identified in later processing based upon the sampling provided by the different sampling clock signals. NYFR sampling receivers are also disclosed that simultaneously produce multiple separate and different parallel channels from an input signal, with each different channel having a different sampling clock sampling rate from the other channels so as to generate a respective folding pattern that is different from the folding pattern generated by the respective RF sampling rate of each of the other simultaneous and parallel channels.

Abstract: Systems and methods are disclosed for detecting and/or measuring signals contained in modulated sample data, and that may be implemented in one embodiment to detect and measure signals by producing a representation and/or visualization of the signal information of the wide band spectral environment. Signals may be detected and/or measured by demodulating and estimating signal spectra from the modulated sample data that contain the individual signals, and by then forming a frequency representation of the demodulated Nyquist zone spectral estimates into a visual representation in which the frequency of the original signals is visible or otherwise indicated.

Abstract: Systems and methods are disclosed for detecting and/or measuring signals contained in modulated sample data, and that may be implemented in one embodiment to detect and measure signals by producing a representation and/or visualization of the signal information of the wide band spectral environment. Signals may be detected and/or measured by demodulating and estimating signal spectra from the modulated sample data that contain the individual signals, and by then forming a frequency representation of the demodulated Nyquist zone spectral estimates into a visual representation in which the frequency of the original signals is visible or otherwise indicated.

Abstract: Methods and systems are disclosed herein for discriminating phase-shift-key (PSK) modulated signals from frequency-shift-key (FSK) modulated signals in received signal streams. First, a bit frequency analysis is applied to a digital signal stream representing the received signal stream. The bit frequency analysis computes bit frequencies for bit segments within the digital signal stream. These bit frequencies are then summed in an array to form a bit frequency histogram. Second, a bit phase analysis is applied to the digital signal stream. The bit phase analysis computes bit phases for bit segments within the digital signal stream. These bit phases are then summed in an array to form a bit phase histogram. Spikes within the bit frequency and bit phase histograms can be used to determine whether the received signal stream includes FSK or PSK signals. An enhanced bit phase analysis can also used, if needed.

Abstract: Systems and methods for detecting and/or identifying signals that employ streaming processing to generate time-frequency surfaces by sampling a datastream according to a temporal structure that may be chosen as needed. The sampled datastream may be correlated with a set of templates that span the band of interest in a continuous manner, and used to generate time-frequency surfaces from irregularly sampled data with arbitrary structure that has been sampled with non-constant and non-Nyquist sampling rates where such non-constant rates are needed or desired.

Abstract: Methods and systems are disclosed herein for discriminating phase-shift-key (PSK) modulated signals from frequency-shift-key (FSK) modulated signals in received signal streams. First, a bit frequency analysis is applied to a digital signal stream representing the received signal stream. The bit frequency analysis computes bit frequencies for bit segments within the digital signal stream. These bit frequencies are then summed in an array to form a bit frequency histogram. Second, a bit phase analysis is applied to the digital signal stream. The bit phase analysis computes bit phases for bit segments within the digital signal stream. These bit phases are then summed in an array to form a bit phase histogram. Spikes within the bit frequency and bit phase histograms can be used to determine whether the received signal stream includes FSK or PSK signals. An enhanced bit phase analysis can also used, if needed.

Abstract: Systems and methods for detecting and/or identifying signals that employ streaming processing to generate time-frequency surfaces by sampling a datastream according to a temporal structure that may be chosen as needed. The sampled datastream may be correlated with a set of templates that span the band of interest in a continuous manner, and used to generate time-frequency surfaces from irregularly sampled data with arbitrary structure that has been sampled with non-constant and non-Nyquist sampling rates where such non-constant rates are needed or desired.