[PD] Re: [PD-announce] PWM in Pd

[Hans-Christoph Steiner]

On May 25, 2006, at 5:47 PM, Frank Barknecht wrote:

> Hallo,
> Hans-Christoph Steiner hat gesagt: // Hans-Christoph Steiner wrote:
>
>> Ah yes, [pwm~] is using zexy's [>~].  I was looking at [pwm].  That
>> example (I am looking at K01.pulse.width.mod.pd from 0.38.4) is very
>> simple, but as it is, it is not usable.  Notice how the LOW and HIGH
>> change values.  PWM needs be 0 for LOW and 1 for HIGH.  That example
>> is usable in an audio context, since DC offset doesn't really
>> matter.  I guess you could rely on the DAC in the soundcard to remove
>> the DC, but that is probably asking for trouble.
>
> Well, the phasor-substraction is the classical analog synth pwm, where
> you can do pwm with substracting two sawtooth waves. It is limited
> because of the DC wandering, but it works quite okay for sound.
>
> Attached is your patch where I replaced the zexy object with a crude
> waveshaper. I also replaced the phase-inlet with a frequency inlet,
> because I think, this is more useful to have than an inlet to reset
> the phase. Of course both inlets would be useful in the end.
>
> Attached patch is more a proof of concept and not recommended for real
> use.

I should say, I forgot that PWM was used in synthesis some, so I was  
thinking about electronics and control when I was talking about PWM.   
That's why my PWM objects are tailored towards, but should work fine  
in the audio context too, unless you need the wandering DC offset.

.hc

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