gentone

Command-line program for writing audio wav files of pure tones and synth waveforms.

Installation

Use gcc to compile.

For UNIX systems type:

git clone https://github.com/fergarciadlc/gentone.git
cd gentone/
sudo gcc gentone.c waveform.c savewav.c -lm -w -o /usr/local/bin/gentone

For Windows: clone or download this repository, open a terminal in the directory and type:

gcc gentone.c waveform.c savewav.c -o gentone

Then, place the gentone.exe file in any location on your PATH (except for C:\Windows\System32).

Usage

Generate a wav file of a pure tone by typing:

gentone -f <(Hz)> [OPTIONS]

where:

-f 	Frequency of the signal in Hertz (Mandatory argument)

Options:

-t	Time of the signal in seconds	(default: 1 s)
-a 	Amplitude of the signal (0-1)   (default: 1)
-s 	Sampling frequency in Hertz 	(default: 44100 Hz)
-b 	Bit depth, only 16 or 8		(default: 16 bits)
-w      Waveform:   <sine>   (default)
                   <square>
	          <triangle>
		  <sawtooth>
-d	Phase Shift in degrees 		(default: 0)
-r	Phase Shift in radians		(default: 0)
-N 	filename (default: "[freq]Hz--waveform--date--time.wav")

Type gentone -h to see the usage and help.

Example

Type:

gentone -f 220 -t 5

Output:

File: '220.00Hz--sine--19-Jun-2020--23-37-36.wav' generated.  

Values:
  Frequency = 220.00 Hz
  Duration  = 5.00 s
  Amplitude = 1.00
  Waveform = 'sine'
  Phase Shift = 0.0000 rad
  Fs = 44100.00 Hz
  Bit depth = 16 bits

And it will generate a 5 seconds wav file of a 220 Hz pure tone (sine function) with the rest of the default values.

Supported waveforms

• Sine
• Square
• Triangle
• Sawtooth

Espacial case: Aliasing

The program is aware of the Nyquist-Shannon sampling theorem and whenever the signal's frequency is greater than the double of the sampling frequency (for instance: gentone -f90 -s100) it will show the following warning:

WARNING: Nyquist-Shannon sampling theorem:
100.00 Hz sampling frequency is less than 2x(90.00 Hz)

And then will generate the file that could be useful to show/explain the Aliasing effect.

License:

Copyright (c) 2020 Fernando García de la Cruz

Licensed under the MIT License.