Triangle Wave

Also, triangular wave. An audio waveform theoretically comprised of an infinite set of odd harmonic sine waves. It is often used in sound synthesis where its timbre is less harsh than the square wave because the amplitude of its upper harmonics falls off more rapidly.

See: Fourier Theorem, Oscillator. Compare: Pulse, Sawtooth Wave.

Triangular wave, its description as a Fourier series, and as a line spectrum.