Signal generator
1. Electronic
An electronic oscillator is an electronic circuit that is capable of creating a repetitive waveform. The most common is a sinusoidal wave, but ramp, step, square, and triangular wave-form oscillators are possible.
2. Mechanical
A reciprocating or vibrating mechanical device like a piston or a tuning fork are both mechnical oscillators.
3. Mathematical
The mathematical description of an oscillator involves a description of a continuous function that varies cyclically above and below a mean or other reference, extending from -infinity to +infinity, never fading, never diverging. This can be represented as a sequence:
For example the sequence 1, -1, 1, -1, 1, -1,... is an oscillation that is analogous to a square-wave generator. [This paragraph is horribly written; a mathematician who knows the conventions of this area could correct it. I have changed the incorrect word "series" to "sequence".]
See also:
We need to have something on ollliscopes here, but too bad, so sad, YOU LOSE. We don't have anything and neither does ANYONE ELSE on the entire internet so DON'T EVEN BOTHER LOOKING! Yeah I was gonna do my science fair project on those but i couldn't find a ring-a-ding darn thing about them ANYWHERE!