Classes | UGens > Generators > Deterministic

Impulse : PureUGen : UGen : AbstractFunction : Object

Impulse oscillator.


Outputs non-bandlimited single sample impulses.

Class Methods 440.0, phase: 0.0, mul: 1.0, add: 0.0) 440.0, phase: 0.0, mul: 1.0, add: 0.0)



Frequency in Hertz. freq may be negative.


Phase offset in cycles (0..1). Staying in this range offers a slight efficiency advantage, though phase offsets outside this range are supported and wrapped internally.


The output will be multiplied by this value.


This value will be added to the output.


Impulse will output a 1.0 on the first sample (assuming no phase offset).

If the initial freq = 0, a single impulse is output on first sample, followed by silence until the frequency changes.

Supported rate combinations for (freq, phase) are (a,a), (a,k), (a,i), (k,k), (k,i), (i,k), (i,i).

Impulse is based on a wrapping phasor: phase advances on each frame and if the phase goes out of range and is wrapped in that frame, an impulse is output.

Internally, the phase offset value is applied and wrapped into range before applying the phase increment (which is determined by the freq). After this phase increment, the trigger condition is checked. Therefore, it is the phase increment (freq) that triggers an impulse, not the phase offset.

For example, if you wanted to create an impulse train by setting freq: 0 and modulating the phase offset directly, Impulse would not support that. However, a you could generate an impulse train by phase modulation using the rate parameter of a Phasor, like this:

Inherited class methods

Instance Methods

Inherited instance methods

Undocumented instance methods



modulate phase:

an Impulse with frequency 0 returns a single impulse: