Main Content

Scalogram of Hyperbolic Chirp

Use Signal Analyzer to display a hyperbolic chirp and its scalogram. This example requires a Wavelet Toolbox™ license.

Generate a signal sampled at 1 kHz for 1 second. The signal consists of two hyperbolic chirps. One of the chirps is active between 0.1 second and 0.68 second. The other chirp has twice the amplitude and one-third of the instantaneous frequency of the first chirp. The second chirp is active between 0.1 second and 0.75 second.

n = 1000;
t = (0:n-1)/n;

ff = [1 2]*(sin(pi*[15 5]'./(t-0.8001)).*(t>0.1 & t<[0.68 0.75]'));

The chirp is modulated by an envelope that starts at 0.1 second and is nonzero for 0.7 second.

envl = zeros(size(t));
M = 0.7*n;
envl(n/10+(1:M)) = tukeywin(M,0.8);

nw = ff.*envl;

Display the signal in Signal Analyzer. Click Time-Frequency ▼ on the Display tab and select Scalogram.


On the Scalogram tab, set the Voices Per Octave to the maximum value. Set the lower magnitude limit to 0.5.

See Also



Related Examples

More About