TriangleWave

A source unit that can generate a range of triangle-shaped signals such as the triangle wave and the sawtooth wave. The signal can be adjusted by changing the period and/or frequency of the oscillation.

The width parameter represents the “turning point” during the period at which the signals reaches its maximum and starts going down again. Changing the width allows to generate different kinds of triangular-shaped waves. For example, by setting width to 1.0 (100%) one obtains a sawtooth wave; by setting it to 0.0 (0%) an inverted sawtooth is created; anything in between generates different flavors of triangle waves.

_images/Plaquette-TriangleWave-Width.png

Example

Controls a set of traffic lights that go: red, yellow, green, red, yellow, green, and so on. It uses a sawtooth to iterate through these three states.

#include <Plaquette.h>

DigitalOut green(10);
DigitalOut yellow(11);
DigitalOut red(12);

TriangleWave osc(10.0);

void begin() {
  osc.width(1.0); // sawtooth wave
}

void step() {
  // Shut down all lights.
  0 >> led >> yellow >> green;
  // Switch appropriate LED.
  if (osc < 0.4)
    green.on();
  else if (osc < 0.6)
    yellow.on();
  else
    red.on();
}

class TriangleWave : public AbstractWave

Triangle/sawtooth oscillator.

Public Functions

virtual void period(float period)

Sets the period (in seconds).

Parameters:: period – the period of oscillation (in seconds)

virtual void frequency(float frequency)

Sets the frequency (in Hz).

Parameters:: frequency – the frequency of oscillation (in Hz)

inline virtual float frequency() const: Returns the frequency (in Hz).

virtual void bpm(float bpm)

Sets the frequency in beats-per-minute.

Parameters:: bpm – the frequency of oscillation (in BPM)

inline virtual float bpm() const: Returns the frequency (in BPM).

virtual void width(float width)

Sets the width of the signal as a % of period.

Parameters:: width – the width as a value in [0, 1]

inline virtual float width() const: Returns the width of the signal.

virtual void amplitude(float amplitude)

Sets the amplitude of the wave.

Parameters:: amplitude – a value in [0, 1] that determines the amplitude of the wave (centered at 0.5).

inline virtual float amplitude() const: Returns the amplitude of the wave.

virtual void phase(float phase)

Sets the phase (ie.

the offset, in % of period).

Parameters:: phase – the phase (in % of period)

inline virtual float phase() const: Returns the phase (in % of period).

virtual float shiftBy(float phaseShift)

Returns oscillator’s value with given phase shift (in %).

Supports negative phase shifts. Eg. shiftBy(0.2) returns future value of oscillator after 20% of its period would have passed.

Parameters:: phase – the phase shift (in % of period)
Returns:: the value of oscillator with given phase shift

inline virtual float get(): Returns value in [0, 1].

inline virtual float mapTo(float toLow, float toHigh): Maps value to new range.

TriangleWave

Example

See Also