When two signals are multiplied together, the amplitude of one signal modulates the amplitude of the other signal. In audio, it is common to use a low-frequency oscillator (LFO) as the modulator. The other input signal is commonly called the carrier signals.
The amplitude of the LFO periodically increases and decreases the amplitude of the carrier signal. The frequency of the LFO has an important impact on the process. Usually the frequency is selected to be less than 20 Hz.
Another way to change the LFO is to modify the type of signals. There are several common types of LFOs including the sine wave, square wave, and triangle wave.
The process of amplitude modulation is the basis of the Tremolo effect. Next, let’s explore more of the features of this specific effect.