I have a digital audio signal (float samples). I need to apply the Vibrato effect to a signal. "Vibrato" is no common term, but it is the same as the frequency modulation.
So, I need to modulate my audio signal by a low-frequency sinusoid. I need to set two parameters for the modulation: "amplitude" and period. In this case, "amplitude" of freq modulation is a maximum shift of signal frequency, for example 10 Hz. Period is just a period of the sinusoid.
So, I need a C/C++ function for such modulation.
The related article, but I cannot quite understand it: https://christianfloisand.wordpress.com/2012/05/01/shaking-it-up-with-vibrato-2/