Overview

General purpose periodic function generator

Discussion

General purpose function generator, with parameters for controlling frequency, amplitude and start phase. The module can generate Sine wave, Square wave, Triangle wave, Sawtooth wave and Impulse with the control parameter, functionType. If functionType = 0 generates Sine wave, functionType = 1 generates Square wave, functionType = 2 generates Triangle wave, functionType = 3 generates Sawtooth wave, . and functionType = 4 generates Impulse wave.

Type Definition

typedef struct _ModulePeriodicFunctionGen
{
    ModuleInstanceDescriptor instance;            // Common Audio Weaver module instance structure
    INT32 functionType;                           // Type of the wave form to be generated on output
    FLOAT32 freq;                                 // Frequency of the function generator output wave.
    FLOAT32 amplitude;                            // Amplitude in linear units.
    FLOAT32 offset;                               // Starting phase of the function generator output wave.
    FLOAT32 offsetRad;                            // Offset in radiuns.
    FLOAT32 phase;                                // Instantanteous phase and also starting phase.
    FLOAT32 phaseInc;                             // Instantaneous sample to sample phase increment.
    INT32 impPeriod;                              // Period or rate of the impulse generator.
    INT32 impSampleIndex;                         // Specifies the index of the next non-zero value.
    FLOAT32 triPhase;                             // Instantanteous phase and also starting phase.
    FLOAT32 triPhaseInc;                          // Instantaneous sample to sample phase increment.
    FLOAT32 sawPhase;                             // The stored phase of the sawtooth function.
    FLOAT32 sawPhaseIncrement;                    // The amount that the oscillator phase is incremented for each output sample.
} ModulePeriodicFunctionGenClass;

Variables

Properties

Name	Type	Usage	isHidden	Default value	Range	Units
functionType	int	parameter	0	0	0:4
freq	float	parameter	0	1000	0.01:24000	Hz
amplitude	float	parameter	0	1	0:2	linear
offset	float	parameter	0	0	0:360	degrees
offsetRad	float	derived	1	0	Unrestricted
phase	float	state	1	0	Unrestricted	radians
phaseInc	float	derived	1	0.1309	Unrestricted	radians/sample
impPeriod	int	derived	1	48	Unrestricted	samples
impSampleIndex	int	state	1	0	Unrestricted
triPhase	float	state	1	0	Unrestricted
triPhaseInc	float	derived	1	0.08333	Unrestricted
sawPhase	float	state	1	0	Unrestricted
sawPhaseIncrement	float	derived	1	0.04167	Unrestricted

Pins

Output Pins

Name: out

Description: audio output

Data type: float

MATLAB Usage

File Name: periodic_function_gen_module.m

 M=periodic_function_gen_module(NAME, SR, BLOCKSIZE)
 Creates a general purpose function generator for use in the Audio Weaver 
 environment. This module has a single channel output pin with controllable 
 frequency. The output of the module changes instantly when the frequency 
 is updated. This module can generate sine wave, square wave, trinagular
 wave, sawtooth wave and impulse with control variable.
  
 Arguments:
    NAME - name of the module.
    SR - sample rate.
    BLOCKSIZE - number of samples per output channel.