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