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The LFO CHOP (low frequency oscillator) generates waves in real-time in two ways. It synthesizes curves using a choice of common waveforms like Sine or Pulse, or it repeats a prepared incoming curve.

It steps through the waveform at a rate that depends on the Frequency parameter and the Octave Control input. To watch its behavior, attach a Trail CHOP to its output and alter the Frequency parameter.

Up to three input CHOPs can be connected to the LFO CHOP:

Octave Control - Without this first (optional) input, the frequency is simply the Frequency parameter. If this input is connected, every unit doubles the frequency: When Octave Control is 1, the frequency is double, when it is 2 it is 4x, when it is -1 the frequency is half the Frequency parameter and when it is 0, there is no change in the frequency.

Reset - The seond (optional) input contains on-off (<=0 or >0) that restarts the channels of the oscillator from the beginning of the wave. The reset depends on the setting of the Reset Condition menu. By default, when the Reset input goes from off to on, it resets the wave and starts the waveform immediately. If Reset Condition is set to "While On", the reset value will be held until the Reset input goes off. Reset means "stop the oscillator and cue it at the start of the waveform".

Source Wave - The third (optional) input is a replacement of the waveform Type. It is a multi-sample CHOP curve and can contain any number of channels, limited to the channels defined on the Channel page. The waveform Type parameter is disabled.

The LFO CHOP can serve as a general motion time-warper and repeater. If you alter the Frequency, you can control the time warp.

Unlike the Wave CHOP, this is a time-sliced CHOP, that is, it generates its waveform as it goes, and speeds/slows how it steps through the waveform Type while the Frequency changes. Unlike the Audio Oscillator CHOP, the LFO CHOP is designed for non-audio frequencies.

See also: Audio Oscillator CHOP, Wave CHOP, Pulse CHOP.


Parameters - LFO Page

Type wavetype - - The shape of the waveform to repeat, unless overridden by the Source Wave:

  • Sine sin - TouchChannels71.gif(-1 to 1) A Sine wave.
  • Gaussian normal - TouchChannels74.gif(0 to 1) A Gaussian (also known as a bell or normal) curve.
  • Triangle tri - TouchChannels76.gif(-1 to 1) A ramp-up to 1 and ramp-down to -1 that can be shaped with the Bias parameter.
  • Ramp ramp - TouchChannels78.gif(0 to 1) A ramp from 0 to 1.
  • Square square - TouchChannels80.gif(-1 to 1) Step-up/step-down, with Bias control to make it rectangular.
  • Pulse pulse - TouchChannels82.gifProduces a 1 for one sample, 0 otherwise.

Play play - The LFO oscillates when 1, and stops when 0. Think of it like play and pause.

Frequency frequency - The cycles per second of the oscillation. When the Octave Control input is connected, it alters the frequency exponentially.

Offset offset - Values output from the CHOP can have an offset added to them.

Amplitude amp - Values output from the CHOP can be scaled.

Bias bias - Shape control for Triangle, Gaussian and Square waves. For triangle waves, it moves the peak. For square waves, it alters the width of the peak. Zero means no bias.

Phase phase - A value of .5 is a phase shift of 180 degrees, or one half cycle.

Reset Condition resetcondition - - This menu determines how the Reset input triggers resetting the channel(s).

  • Off to On offtoon - Channels are reset when the Reset input goes off to on.
  • While On on - Channels are reset when the Reset input goes on. The channel will hold the reset value until the input turns off.
  • On to Off ontooff - Channels are reset when the Reset input goes on to off.
  • While Off off - Channels are reset when the Reset input goes off. The channel will hold the reset value until the input turns on.

Reset reset - This toggle resets the channel(s) to 0 while On.

Reset Pulse resetpulse - This button instantly resets the channel(s) to 0.

Parameters - Channel Page

Channel Name channelname - A list of the names of the channels. You can put patterns like chan[1-10] to generate 10 channels. See Pattern Expansion.

Each channel can be different by putting the channel index variable, $C in parameters like the frequency channel.

Sample Rate rate - The sample rate of the CHOP. The default sample rate is 60 samples per second.

Parameters - Common Page

Time Slice timeslice - Turning this on forces the channels to be "Time Sliced". A Time Slice is the time between the last cook frame and the current cook frame.

Scope scope - To determine which channels get affected, some CHOPs use a Scope string on the Common page.

Sample Rate Match srselect - - Handle cases where multiple input CHOPs' sample rates are different. When Resampling occurs, the curves are interpolated according to the Interpolation Method Option, or "Linear" if the Interpolate Options are not available.

  • Resample At First Input's Rate first - Use rate of first input to resample others.
  • Resample At Maximum Rate max - Resample to the highest sample rate.
  • Resample At Minimum Rate min - Resample to the lowest sample rate.
  • Error If Rates Differ err - Doesn't accept conflicting sample rates.

Export Method exportmethod - - This will determine how to connect the CHOP channel to the parameter. Refer to the Export article for more information.

  • DAT Table by Index datindex - Uses the docked DAT table and references the channel via the index of the channel in the CHOP.
  • DAT Table by Name datname - Uses the docked DAT table and references the channel via the name of the channel in the CHOP.
  • Channel Name is Path:Parameter autoname - The channel is the full destination of where to export to, such has geo1/transform1:tx.

Export Root autoexportroot - This path points to the root node where all of the paths that exporting by Channel Name is Path:Parameter are relative to.

Export Table exporttable - The DAT used to hold the export information when using the DAT Table Export Methods (See above).

Operator Inputs

  • Input 0: -
  • Input 1: -
  • Input 2: -

Info CHOP Channels

Extra Information for the LFO CHOP can be accessed via an Info CHOP.

Common CHOP Info Channels

  • start - Start of the CHOP interval in samples.
  • length - Number of samples in the CHOP.
  • sample_rate - The samplerate of the channels in frames per second.
  • num_channels - Number of channels in the CHOP.
  • time_slice - 1 if CHOP is Time Slice enabled, 0 otherwise.
  • export_sernum - A count of how often the export connections have been updated.

Common Operator Info Channels

  • total_cooks - Number of times the operator has cooked since the process started.
  • cook_time - Duration of the last cook in milliseconds.
  • cook_frame - Frame number when this operator was last cooked relative to the component timeline.
  • cook_abs_frame - Frame number when this operator was last cooked relative to the absolute time.
  • cook_start_time - Time in milliseconds at which the operator started cooking in the frame it was cooked.
  • cook_end_time - Time in milliseconds at which the operator finished cooking in the frame it was cooked.
  • cooked_this_frame - 1 if operator was cooked this frame.
  • warnings - Number of warnings in this operator if any.
  • errors - Number of errors in this operator if any.

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