A method for data transmission includes forming a notched radio-frequency
(RF) burst according to one or more data values, where a bandwidth of the
notched RF burst is at least two percent of the center frequency of the
notched RF burst. Forming a notched RF pulse includes altering, according
to the data, at least one of the amplitude and phase of one or more
selected components, where each of the selected components has a
bandwidth within the bandwidth of the notched RF burst.