.TH ENVELOPE 1carl CARL
.SH NAME
envelope \- plot high-resolution temporal envelope of a signal
.SH SYNOPSIS
.B envelope
< floatsams > floatsams
.SH DESCRIPTION 
.I envelope
produces on stdout a very high-resolution temporal envelope of the
signal on stdin.  Mathematically, the envelope is obtained as the
magnitude of the analytic signal
.IP
z(n) = x(n) + j x^(n)
.LP
where x(n) is the input signal and x^(n) is the
hilbert transform of the input signal.
This envelope is like the envelope produced by
.I energy,
but it has none of the temporal smearing which typifies envelopes
produced by
.I energy.
If such smearing is desired, it can be introduced in
a controlled fashion by filtering the output of 
.I envelope
with an appropriate filter.  In the absence of filtering, the
output of
.I envelope
is of such high resolution that it can be played and recognized.
Whether this has any musical application is questionable.
.SH AUTHOR
Mark Dolson

