Additional illustration of a pulse train according to (4). Panel I of the figure shows simulated instantaneous total power response of quadrature receivers tuned to 1- and 3-GHz frequencies (green and black lines, respectively) to an amplitude-modulated 2-GHz carrier of unit power. The squared impulse response of the low-pass filters in the receiver channels is shown in the upper right corner of the panel. Panels II(a) and II(b) of the figure show the modulating signal and its first derivative, respectively. For the modulating signal shown in the figure, n = 2 in (2). The lower panel of the figure shows instantaneous total power response of a quadrature receiver as a spectrogram in the time window w(t) shown in the upper left corner of the panel.