# chirp: A chirp signal In signal: Signal Processing

## Description

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

## Usage

 ```1 2``` ```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

 ``` 1 2 3 4 5 6 7 8 9 10``` ```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")) ```

### Example output

```Attaching package: 'signal'

The following objects are masked from 'package:stats':

filter, poly
```

signal documentation built on May 25, 2021, 9:06 a.m.