[chuck-users] phase modulation and hard sync?

Alexandre Torres Porres porres at gmail.com
Sun Jun 4 12:20:55 EDT 2017

2pi is already there if you are using a phase input, cause it seems the
phase is normalized (0 to 1 instead of 0 - 2pi) in Chuck.

What I mean is how to implement the same result with both frequency and
phase modulation in a Chuck code, using SinOsc.

All these things have to be adjusted

But if the phase input wasn't normalized to 0-1, like is the case with
SuperCollider, you don't need it.


2017-06-04 13:09 GMT-03:00 mario.buoninfante <mario.buoninfante at gmail.com>:

> Hi Alexandre,
> In my implementation there's​ no need to use 2pi. That is required if
> you're using a phasor (in math terms). In that case you need 2pi to have
> the angular frequency. But if you're using instead a Sine wave there's no
> need, cause 2pi is already there.
> Looking at the formula I posted before, the Fm oscillator is the phase
> parameter, while the Cm is the frequency. You can consider them as an
> offset (Cm) and an deviation from it (Fm).
> The index mod is equal to Am/Fm, but of course the parameter that you can
> use with an oscillator is the amplitude (Am), thus from the previous one
> you have Am = Fm*modInd
> Cheers,
> Mario
> Sent from my Wiko ROBBY
> On Jun 4, 2017 16:39, Alexandre Torres Porres <porres at gmail.com> wrote:
> btw, for adjusting the index, you're just multiplying the frequency to the
> index, you should also multiply it by 2pi (like Jean found out by accident).
> 2017-06-04 12:29 GMT-03:00 Alexandre Torres Porres <porres at gmail.com>:
> 2017-06-04 4:24 GMT-03:00 mario buoninfante <mario.buoninfante at gmail.com>:
> this is the simplest modulation, that usually is considered as FM, but in
> the end is a PM.
> Well, as I see it, it should be either FM or PM, it can't be one but in
> the end is something else. And your code is can only (not usually) be
> considered FM.
> But it seems you're saying both are related, without getting into details
> - which is something we've already discussed here, and I've also pointed
> out (with no details either). But the bottom line is that they're
> different, and the same input parameters generate different results. Though
> I've said before the parameters can be "converted"/"adjusted" to sound
> the same.
> Namely, the same modulation index does not generate the same result (Jean
> noticed that), and I can add the detail that the same modulating
> signal/waveform generate different results too. For example, a triangular
> wave modulating the phase is the same as a square wave modulating the
> frequency. So, they're quite different.
> In terms of sine waves, what we've been doing so far, if you modulate the
> phase with a sine wave, you need to modulate the frequency with a cosine
> wave.
> Like I pointed before, if you're going for a phase modulation
> implementation, you should just modulate the phase instead of trying to
> replicate it via frequency modulation, cause it's just more convenient to
> do directly via phase modulation if you want it to behave like that.
> And that noted, several FM modules are not actually implemented via
> frequency modulation, but phase modulation (i.e DX7 and native's
> instruments FM8).
> Anyway, performing FM in Chuck is easy and straightforward, it was never a
> question. The relationship between FM and PM was known and does not really
> mean they're both the same thing.
> Hence, there's still a need to quest for an easy implementation of phase
> modulation.
> cheers
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