Detecting signals that are long, weak, and narrowband is a well known and important
problem in acoustic signal processing. In this paper an ad hoc scheme is developed: its
stages include the DFT, a multiresolution decomposition in the frequency domain, and a
GLRT. The computational load is light, and the performance is remarkably good. This is so
not just in the original narrowband situation, but also, due to an inherent adaptivity to the
data, in the detection of signals that are relatively broadband in nature. Generalizations are …