Pulse Wave Oscillator

Overview

Pulse Wave

The pulse wave oscillator programmatically generates a pulse waveform with specified pulse width. The basic_pulse_osc is not bandwidth limited, while pulse_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.

Include

#include <q/synth/pulse_osc.hpp>

Declaration

struct basic_pulse_osc
{
   constexpr         basic_pulse_osc(float width = 0.5);

   constexpr void    width(float width);
   constexpr float   operator()(phase p);
   constexpr float   operator()(phase_iterator i);
};

struct pulse_osc : basic_pulse_osc
{
   constexpr         pulse_osc(float width = 0.5);

   constexpr float   operator()(phase p, phase dt) const;
   constexpr float   operator()(phase_iterator i) const;
};

Expressions

basic_pulse_osc is a model of BasicOscillator and implements all valid expressions of BasicOscillator. pulse_osc is a model of BandwidthLimitedOscillator and implements all valid expressions of BandwidthLimitedOscillator.

In addition to valid expressions for BasicOscillator and BandwidthLimitedOscillator, basic_pulse_osc and pulse_osc allow these expressions.

Notation

w

A floating point value from 0.0 to 1.0 representing pulse width.

ps

Object of type basic_pulse_osc or pulse_osc

Constructor

Expression Semantics

basic_pulse_osc(w)

Construct a basic_pulse_osc given a pulse width, w

pulse_osc(w)

Construct a pulse_osc given a pulse width, w
C++ brace initialization may also be used.

Mutators

Expression Semantics

ps.width(w)

Set the basic_pulse_osc or pulse_osc pulse width to w.