Low Frequency Oscillator. An oscillator whose output is infrasonic, typically used as a control source for modulating the sound to create vibrato, tremolo, trills, and so on. Unlike a normal oscillator which produces audio signals, an LFO is a generator module that produces a modulation/control signal. The LFO’s signal output is in the form of a slow, periodic waveform, usually less than 20 Hz. The most common parameters found in the LFO are depth, frequency (rate control) and waveform selection.
See Appendix C.