## ChirpSignal.jl

Chirp Swept-frequency sine generator.
Author sonosole
Popularity
0 Stars
Updated Last
5 Months Ago
Started In
January 2021

# ChirpSignal

Chirp Swept-frequency sine generator.

## Installation

Enter the REPL mode and add the module from the latest repository by :

`]add https://github.com/sonosole/ChirpSignal.git`

or from Julia's official registries by :

`]add ChirpSignal`

## Two Public APIs

```chirp(T, fs, fl, fh; method="linear", phase=0.0) -> Array{Float64,1}
chirp(T, fs, f::Function; phase=0.0) -> Array{Float64,1}```

The first API is enough for most usages. Detials could be found via Julia's helping mode.

`help?> chirp`

## Example

### Examples' public code

```using WAV
using ChirpSignal

fs = 16000.0; # sampling frequency
fl = 500.0;   # lower bound frequency
fh = 8000.0;  # upper bound frequency
T  = 5.0 ;    # total time of chirp signal```

### Linear chirp example

```# f(t) = (fh-fl)/T * t + fl
wav = chirp(T, fs, fl, fh; method="linear");
wavwrite(wav, "./doc/chirpLinear.wav", Fs=fs, nbits=32)``` ```# f(t) = k * t^2 + fl, k = (fh-fl)/T^2
wav = chirp(T, fs, fl, fh; method="quadratic"); ### Logarithmic chirp example

```# f(t) = k*log(t+1) + fl, k = (fh-fl)/log(T+1)
wav = chirp(T, fs, fl, fh; method="logarithmic");
wavwrite(wav, "./doc/chirpLogarithmic.wav", Fs=fs, nbits=32)``` ### Exponential chirp example

```# f(t) = exp(k * t) + (fl-1), k = 1/T*log(fh-fl+1)
wav = chirp(T, fs, fl, fh; method="exponential");
wavwrite(wav, "./doc/chirpExponential.wav", Fs=fs, nbits=32)``` ### Customizable chirp example by user's own function

Customizable chirp by specifying `fun(t) = 2000*t`

```fun(t) = 2000*t
wav = chirp(2.0, 16000.0, fun)
wavwrite(wav, "./doc/0_4000hz_linear.wav", Fs=fs, nbits=32)``` ### Customizable chirp example by user's anonymous function

Customizable chirp by specifying a anonymous function `t -> 2000*t^2`

```wav = chirp(2.0, 16000.0, t -> 2000*t^2 ) For `method="linear"` and `method="quadratic"` cases, the lower bound frequency `fl` could be set lager than the upper bound frequency `fh`, but not for the `method="logarithmic"` and `method="exponential"`.