Saw-Tooth Wave Oscillator
Overview
The saw-tooth wave oscillator programmatically generates the waveform. The result is basically just the phase, centered around zero, producing an amplitude of ±1.0. The basic_saw_osc is not bandwidth limited, while saw_osc is, using a technique called "PolyBLEP" to reduce aliasing artifacts that can occur when generating the waveform with a sharp discontinuity as the signal transitions from -1.0 to 1.0.
PolyBLEP works by precalculating a correction function that subtracts the waveform’s high-frequency components at discontinuities. This correction function is then applied to the generated waveform, effectively removing frequencies above the waveform’s Nyquist frequency to avoid aliasing artifacts.
Declaration
struct basic_saw_osc
{
constexpr float operator()(phase p) const;
constexpr float operator()(phase_iterator i) const;
};
constexpr auto basic_saw = basic_saw_osc{};
struct saw_osc
{
constexpr float operator()(phase p, phase dt) const;
constexpr float operator()(phase_iterator i) const;
};
constexpr auto saw = saw_osc{};Expressions
basic_saw_osc is a model of BasicOscillator and implements all valid expressions of BasicOscillator. saw_osc is a model of BandwidthLimitedOscillator and implements all valid expressions of BandwidthLimitedOscillator.
basic_saw_osc and saw_osc are stateless. The global instances basic_saw and saw can be used anywhere without needing to be placed in a class or struct. They are semantically equivalent to global functions.