Basic formal unit in MUSIC-N-style programming languages
Unit generators (or ugens) are the basic formal units in many MUSIC-N-style computer music programming languages.[1] They are sometimes called opcodes (particularly in Csound)[2], though this expression is not considered accurate in that these are not written directly as machine-level instructions.[citation needed]
Unit generators form the building blocks for designing synthesis and signal processing algorithms in software.[3]
The unit generator theory of sound synthesis was first developed and implemented by Max Mathews[4] and his colleagues at Bell Labs in the 1950s.[5]
Examples
A simple unit generator called OSC could generate a sinusoidal waveform of a specific frequency (given as an input or argument to the function or class that represents the unit generator). ENV could be a unit generator that delineates a breakpoint function. Thus ENV could be used to drive the amplitude envelope of the oscillator OSC through the equation OSC*ENV. Unit generators often use predefined arrays of values for their functions (which are filled with waveforms or other shapes by calling a specific generator function).
In the SuperCollider language, the .ar method in the SinOsc class[6] inherits methods from an overarching unit generator class (UGen)[3] that generates a sine wave. The example below makes a sine wave at frequency 440, phase 0, and amplitude 0.5.
SinOsc.ar(440, 0, 0.5);
See also
References