SPOTLIGHT: a signal‐processing system for passive SONAR

SPOTLIGHT is an integrated signal‐processing display system which employs a time‐amplitude‐frequency orthogonal display and a hidden line‐removal technique to reduce clutter and create the appearance of a relief map. The signal processor employs an ideal box‐car integrator and overlapped transform methods to allow significant signal‐processing gains from increase integration time. This technique retains the ability to track dynamic changes in signal frequencies which would otherwise be lost during long integration intervals. Identification is provided by amplitude correlation of signals with specific target characteristic relationships. A sliding linear‐amplitude scale provides the display with a dynamic range matched to the signal processor. Cursors which increase the intensity of a few resolution bins may be swept through the selected frequency groups under operator control. The frequency location of the cursors in each group is displayed to the operator in a continuous alphanumeric read out. These cursors may be moved independently or according to the relationships of the groups like a SPOTLIGHT shining on a topological surface.