xdemorse is a GTK+ based Morse code signal decoder. It has an
integer-arithmetic FFT-derived "waterfall" display of the incoming
audio signal's spectrum, as well as a 'scope-like display of the
audio detector's output and status of the mark/space discriminator
("slicer"). xdemorse also has CAT for the FT847 and FT857 and
this can be used to net the receiver's frequency to the incoming
signal, by clicking near its trace in the waterfall display.