Ramp

In general, a ramp refers to any voltage that is steadily raising or falling; quite often it resets when it reaches a target voltage and starts over again. A sawtooth oscillator waveform is sometime referred to as a ramp. Sometimes, the individual stages of an envelope generator are also referred to a ramp as it raises from 0 volts to a maximum level such as 5v for the attack stage, then falls from this peak to the sustain level for the decay stage.