.\" @(#)timeVarSpec	1.4	12/17/92
.NA timeVarSpec
.SD
A time varying spectrum is displayed.
.DE
.LO "~ptolemy/src/domains/sdf/demo"
.DM SDF Universe
.SV 1.4	12/17/92
.AL "Edward A. Lee"
.LD
A signal is generated by filtering white Gaussian noise
and then modulating it with a chirp (a sinusoid with steadily increasing
frequency).
.Ie "chirp signal"
.Ie "spectral estimation"
.Ie "time varying spectrum"
.Ie "spectrum, time varying"
.Ie "waterfall plot"
.Se "Waterfall
Spectral estimates are repeatedly computed using the autocorrelation method,
and displayed using the Waterfall star.  Note that in the display, the
first plot shows a roughly baseband spectrum, while in subsequent
displays the spectrum is centered at successively higher frequencies.
Note also that hidden points are not displayed.  This can be changed
by altering the parameters of the Waterfall star.
.SA
autocorrelation,
powerSpectrum,
Waterfall.
.ES
