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STK band-limited sawtooth wave class. More...
#include <BlitSaw.h>
Public Member Functions | |
BlitSaw (StkFloat frequency=220.0) | |
Class constructor. | |
~BlitSaw () | |
Class destructor. | |
void | reset () |
Resets the oscillator state and phase to 0. | |
void | setFrequency (StkFloat frequency) |
Set the sawtooth oscillator rate in terms of a frequency in Hz. | |
void | setHarmonics (unsigned int nHarmonics=0) |
Set the number of harmonics generated in the signal. | |
StkFloat | lastOut (void) const |
Return the last computed output value. | |
StkFloat | tick (void) |
Compute and return one output sample. | |
StkFrames & | tick (StkFrames &frames, unsigned int channel=0) |
Fill a channel of the StkFrames object with computed outputs. |
STK band-limited sawtooth wave class.
This class generates a band-limited sawtooth waveform using a closed-form algorithm reported by Stilson and Smith in "Alias-Free Digital Synthesis of Classic Analog Waveforms", 1996. The user can specify both the fundamental frequency of the sawtooth and the number of harmonics contained in the resulting signal.
If nHarmonics is 0, then the signal will contain all harmonics up to half the sample rate. Note, however, that this setting may produce aliasing in the signal when the frequency is changing (no automatic modification of the number of harmonics is performed by the setFrequency() function).
Based on initial code of Robin Davies, 2005. Modified algorithm code by Gary Scavone, 2005.
void stk::BlitSaw::setHarmonics | ( | unsigned int | nHarmonics = 0 |
) |
Set the number of harmonics generated in the signal.
This function sets the number of harmonics contained in the resulting signal. It is equivalent to (2 * M) + 1 in the BLIT algorithm. The default value of 0 sets the algorithm for maximum harmonic content (harmonics up to half the sample rate). This parameter is not checked against the current sample rate and fundamental frequency. Thus, aliasing can result if one or more harmonics for a given fundamental frequency exceeds fs / 2. This behavior was chosen over the potentially more problematic solution of automatically modifying the M parameter, which can produce audible clicks in the signal.
Fill a channel of the StkFrames object with computed outputs.
The channel
argument must be less than the number of channels in the StkFrames argument (the first channel is specified by 0). However, range checking is only performed if _STK_DEBUG_ is defined during compilation, in which case an out-of-range value will trigger an StkError exception.
Implements stk::Generator.
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