# chirp: A chirp signal In signal: Signal Processing

 chirp R Documentation

## A chirp signal

### Description

Generate a chirp signal. A chirp signal is a frequency swept cosine wave.

### Usage

``````chirp(t, f0 = 0, t1 = 1, f1 = 100,
form = c("linear", "quadratic", "logarithmic"), phase = 0)
``````

### Arguments

 `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 `"linear"`, `"quadratic"`, or `"logarithmic"`. `phase` phase shift at t=0.

### Details

`'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`

### Value

Chirp signal, an array the same length as `t`.

### Author(s)

Original Octave version by Paul Kienzle. Conversion to R by Tom Short.

### References

Octave Forge https://octave.sourceforge.io/

`specgram`

### Examples

``````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"))
``````

signal documentation built on June 26, 2024, 9:06 a.m.