[chuck-users] phase modulation and hard sync?

mario buoninfante mario.buoninfante at gmail.com
Sun Jun 4 03:24:40 EDT 2017

Hi Alexandre,

about FM and PM (probably my reply is late!), here's a simple 
implementation using oscillators with sync(0):

/// m = mod osc;  c = carrier osc;//
//SinOsc m => Gain g => SinOsc c => dac;//
//Step cm => g; //cm = carrier freq in Hz//
//while( true ){//
//    modInd(10, 250); //arg: modInd, freq mod //
//    cm.next(500);////carrier frequency
//    second => now;//
//fun void modInd( float i, float f ){ //arg: modInd, freq mod//
//    float am; //
//    i*f => am; //(modInd = Am/Fm), then (Am = modInd*Fm)//
//    m.freq(f);//
//    m.gain(am);//

this is the simplest modulation, that usually is considered as FM, but 
in the end is a PM.

without going into details, what's happening is:

FM (t)=sin(ω c t +Φ c + I sin (ω m t +Φ m ))

with ω c = carrier freq, ω m = mod freq, Φ = phase


On 04/06/17 07:34, Alexandre Torres Porres wrote:
> 2017-06-04 2:35 GMT-03:00 Alexandre Torres Porres <porres at gmail.com 
> <mailto:porres at gmail.com>>:
>     It's not easy to explain, but you found the magic number/formula
>     that makes Frequency modulation sound like Phase Modulation.
> Actually, I shouldn't have said this, I don't wanna give you the idea 
> it comes down to this, but there are just too many details I didn't 
> want get into, sorry. What I can say is that you got pretty close, not 
> 100% there yet, and that is not as simple as just doing this every 
> time, it gets more complicated.
> Sorry again for not getting into the math and everything. What I'd 
> like to add is that people use phase modulation 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.
> cheers
> _______________________________________________
> chuck-users mailing list
> chuck-users at lists.cs.princeton.edu
> https://lists.cs.princeton.edu/mailman/listinfo/chuck-users

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