The Signal generator reference article from the English Wikipedia on 24-Apr-2004
(provided by Fixed Reference: snapshots of Wikipedia from wikipedia.org)

Signal generator

Have you considered sponsoring a child

A signal generator is a box with a variable frequency dial, a waveform selector an attenuator, and a least one pair of output plugs. See diagram on the right.
Image:Signal Generator.png
It contains an electronic oscillator, an electronic circuit that is capable of creating a repetitive waveform. The most common is a sine wave, but sawtooth, step, square, and triangular waveform oscillators are commonly available.

In musical sound synthesis, oscillators conventionally form the most fundamental synthesis building block. With analog synthesizers, they are realized as electronic oscillators and with digital or software synthesizers they are generated algorithmically. Modern software synthesis environments such as CSound have generalized the oscillator as a type of unit generator (UG), where UGs are primitive modules that produce, modify or acquire audio or control signals.