Oscillators

Oscillators are fundamental entities in the universe. Wind over water produces oscillations on the surface. Water waves are good models for all manner of waves. Musical instruments are oscillators that create waves in air that act much like waves in water but are invisible. Electronic oscillators with a frequency of 20 to 20,000 cycles per second (Hertz) produce sound waves when played through an amplifier and speakers. In synthesizers the primary oscillators produce both the pitch and the timbre of instrument sounds.

In the human larynx, the vocal chords are oscillators that vibrate when air passes over them. The pitch of the voice is determined by the tension applied to the vocal chords by muscles and the rate of flow of air. A well trained singer will practice breath control creating notes in a range of about two octaves that are accurate to pitch and have a pleasing quality. Vibrato is added by oscillating laryngeal muscles.

In synthesizers, low frequency oscillators, LFO, operated in a range of about 1 to 60 HZ are used to modify the main frequency of sound. If the main pitch is modified by an LFO, the effect is tremolo. If the amplitude of the pitch is modified, the effect is vibrato. A violinist changes the note pitch by finger pressure on a string and then oscillates his finger to produce vibrato. Sustained notes on the violin are less pleasing without vibrato.

Low Frequency Oscillators available in the Proteus 2500 and Emulator X2

LFO waveforms available in Proteus 2500 and Emulator X2 synthesizers