A chirp signal
Generate a chirp signal. A chirp signal is a frequency swept cosine wave.
chirp(t, f0 = 0, t1 = 1, f1 = 100,
form = c("linear", "quadratic", "logarithmic"), phase = 0)t |
array of times at which to evaluate the chirp signal. |
f0 |
frequency at time t=0. |
t1 |
time, s. |
f1 |
frequency at time t=t1. |
form |
shape of frequency sweep, one of |
phase |
phase shift at t=0. |
'linear' is:
f(t) = (f1-f0)*(t/t1) + f0
'quadratic' is:
f(t) = (f1-f0)*(t/t1)^2 + f0
'logarithmic' is:
f(t) = (f1-f0)^{t/t1} + f0
Chirp signal, an array the same length as t.
Original Octave version by Paul Kienzle. Conversion to R by Tom Short.
Octave Forge http://octave.sf.net
ch <- chirp(seq(0, 0.6, len=5000)) plot(ch, type = "l") # Shows a quadratic chirp of 400 Hz at t=0 and 100 Hz at t=10 # Time goes from -2 to 15 seconds. specgram(chirp(seq(-2, 15, by=0.001), 400, 10, 100, "quadratic")) # Shows a logarithmic chirp of 200 Hz at t=0 and 500 Hz at t=2 # Time goes from 0 to 5 seconds at 8000 Hz. specgram(chirp(seq(0, 5, by=1/8000), 200, 2, 500, "logarithmic"))
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