A laboratory test instrument, often used in early forms of electronic music including tape studio techniques. A typical function generator can produce many of the same waveforms that are commonly produced by syntheiszer VCOs, such as the sine wave, triangle wave, sawtooth wave, and pulse wave. Some have "symmetry" or "distortion" controls that can produce variations of the shape and therefore the harmonic content of the produced waveforms. Some have the ability to produce "sweeps" in which the frequency is rapidly driven from a low to a high value or vice versa, one time or repeating. Others have the capability to produce special-purpose waveforms which were intended to be used in diagnosis of analog television sets, but for which experimenters found musical applications.