Signal Toolkit - chirp

Function File: chirp (t)

Function File: chirp (t, f0)

Function File: chirp (t, f0, t1)

Function File: chirp (t, f0, t1, f1)

Function File: chirp (t, f0, t1, f1, shape)

Function File: chirp (t, f0, t1, f1, shape, phase)

Evaluate a chirp signal at time t. A chirp signal is a frequency swept cosine wave.

t

vector of times to evaluate the chirp signal

f0

frequency at time t=0 [ 0 Hz ]

t1

time t1 [ 1 sec ]

f1

frequency at time t=t1 [ 100 Hz ]

shape

shape of frequency sweep ’linear’ f(t) = (f1-f0)*(t/t1) + f0 ’quadratic’ f(t) = (f1-f0)*(t/t1)^2 + f0 ’logarithmic’ f(t) = (f1/f0)^(t/t1) * f0

phase

phase shift at t=0

For example:

  specgram (chirp ([0:0.001:5]));  # default linear chirp of 0-100Hz in 1 sec
 specgram (chirp ([-2:0.001:15], 400, 10, 100, "quadratic"));
 soundsc (chirp ([0:1/8000:5], 200, 2, 500, "logarithmic"), 8000);
 

If you want a different sweep shape f(t), use the following:

 y = cos (2 * pi * integral (f(t)) + phase);