| 摘要 |
A frequency-and-direction-finding system (10) employing a circular array (12) performs a two-dimensional Fourier transformation in space and time on the signals from the individual elements. The results of the transformation are fed to multipliers (22) that multiply them by correction factors that are derived from antenna patterns of the array but do not include the bearing-dependent factors in those systems. The result is an ensemble of values whose relative phases represent a spatial frequency proportional to the bearing angle of the source. Accordingly, a second fast-Fourier-transform circuit (26) operating on this ensemble of values produces an output only on an output port corresponding to the bearing angle of the source.
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