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.