WaveWarp 2.0 Component
      
Signal Generators:
Triangular Wave Generator
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Functional Description
Generates an audio signal with a triangular waveform.
For efficiency, the waveform is pre-calculated and
stored in a wavetable (buffer).
NOTE: the sample rate at which this component is executed can be arbitrarily set via the
"Sample-rate setting for Signal Generators and
Input ASCII files" button
(or the "Sample-Rate Setting" command under the "Edit" menu) on the toolbar, which is
activated whenever the component is selected on the DrawingBoard.
Equivalently, it can be set via the dialog box which (i) appears
when the component is initially
dragged on to the DrawingBoard or (ii) is activated using the right-mouse-button when
the component is selected on the DrawingBoard.
This procedure allows the component to either (i) enforce
a user-determined sample rate on the downstream component(s), or (ii) to inherit the sample rate from
the downstream component(s). Different signal generators can run at different
sample rates on a DrawingBoard, as long as the rules of connectivity
for multiple sample rates are adhered to (see the
WaveWarp Users' Guide
for more information.)
The characteristics of the waveform are adjustable via
the Parameter Window, as summarised in the
following table.
| Parameter | Purpose |
|---|
| "Frequency" slider |
Adjusts the frequency of the output signal. When the wavetable is played,
it is scanned at the appropriate rate to generate the desired signal frequency.
The plot window displays the waveform.
The time-scale in the plot
automatically adjusts to reflect the duration of a single waveform cycle (in accordance with
the selected signal frequency).
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| "Amplitude" slider |
Adjusts the amplitude of the output signal.
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| "Skew" slider |
Adjusts the asymmetry of the waveform.
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| "Harmonics" slider |
Activated when "Enable band-limiting" is selected.
Adjusts the number of harmonics used to construct the waveform.
Useful for band-limiting the waveform to avoid
undesirable audible fold-over associated with the finite bandwidth of the digital
representation of an analog waveform.
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Algorithm
The waveform is stored
in a wavetable, and is scanned using a table-lookup oscillator algorithm
(see
[Moore]
section 3.1.7
and
[Roa] p. 90-95
for further information).
For a discussion on band-limited waveforms, see
[Moore] p. 170-171 and
p. 270-273. The harmonic expansion used for the skewed triangular
waveform
was obtained from the appropriate Fourier series expansion (see any elementary applied mathematics
textbook).
Signal Implementations
| Audio signals | Control signals | Description |
|---|
| Single output mono | n/a | Generates a mono signal, sent to the mono output |
| Single output stereo | n/a | Generates a mono signal,
sent (in duplicate) to the stereo output channels |
Related components:
Example DrawingBoards illustrating usage:
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