PWM oscillator with the audio library

P

Phm78

Member
If I understand correctly, the pulseWitdth() class does not exist on a waveformMod object but we can modulate the PWM with an LFO,
If I use a waveform object, the pulseWitdth() class exists but no modulation possibility.
So there is no solution to do both at the same time with a single oscillator?
 
@Phm78: Not sure which of these two options you actually want, so here's a description of each.

VFO, modulated by a mix of PWM & LFO frequency:

Configure one waveform object where you control the pulseWidth() (identified as your PWM object, started with begin(WAVEFORM_PULSE)). Configure a second waveform object where you control the frequency (identified as your LFO object, started with begin(WAVEFORM_SINE), or whatever type of modulation you want). Feed the outputs from these two objects into a mixer, then take the output from that mixer & use that as the modulation input into a third waveform object (identified as your VFO object, started with begin(WAVEFORM_SQUARE)[/ICODE, or whatever primary type of oscillation you want]). Now you have a PWM and/or frequency modulated oscillator, where you should have complete control over the PWM modulation rate (using the [ICODE]frequency() control of the PWM object), the LFO modulation rate (using the frequency() control of the LFO object), as well as the level of each using the mixer control capabilities.

1729249713327.png


VFO, modulated by an LFO whose frequency is PWM modulated:

Configure one waveform object where you control the pulseWidth() (identified as your PWM object, started with begin(WAVEFORM_PULSE)). Configure a second waveform object where you control the frequency (identified as your LFO object, started with begin(WAVEFORM_SINE), or whatever type of modulation you want) feeding the output from the PWM object into the modulation input of the LFO object. Feed the output from the LFO object into the modulation input of a third waveform object (identified as your VFO object, started with begin(WAVEFORM_SQUARE)[/ICODE, or whatever primary type of oscillation you want]). Now you have a PWM modulated LFO, which is then modulating your VFO oscillator, where you should have complete control over the PWM modulation rate (using the [ICODE]frequency() control of the PWM object), the primary LFO modulation rate (using the frequency() control of the LFO object).

1729249986359.png


NOTE: I prefer to use the AudioSynthWaveformModulated for all oscillators (LFOs, VFOs, etc.). That way, I can add modulation to any objects in the future, making it very easy as design of my synthesizer & its capabilities evolve over time.

Hope that helps . . .

Mark J Culross
KD5RXT
 
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