This app can be used to generate different tones by defining the wave form, the frequency and the amplitude. The resulting sound wave is visualized as a graph. By now, the following wave forms are supported: Sine, Square, Triangle and Sawtooth.
Additionally, this app supports ring and amplitude modulation. Modulation means, that the amplitude of carrier wave is changed dynamically by a modulator wave. Basically, the two waves are multiplied. For low modulation frequencies, this creates a tremolo effect. For higher frequencies from about 20hz, the individual vibrations are no longer recognized which causes the creation of frequency side bands. This can create some very interesting sound effects. For further information about how modulation works, I recommend reading the following article: https://en.wikibooks.org/wiki/Sound_Synthesis_Theory/Modulation_Synthesis
For the graph visualization, the open-source library MPAndroidChart is used, which was created by PhilJay and is licensed under the Apache 2.0 license. The github repository to this library can be found under: https://github.com/PhilJay/MPAndroidChart
Version 1.1
Added Pulse Wave: the same as Square Wave, but with configurable duty cycle
Frequency seek bar has a logarithmic scale and a larger range
Amplitude shown as a decimal
Checkbox to deactivate modulation preference to invalid frequency of 0
Changed UI layout
Version 1.0
The following wave forms are supported: Sine, Square, Triangle, Sawtooth
The following modulation types are supported: Ring Modulation and Amplitude Modulation
9Apps 4.9
