Feedback in FM synthesis

[Jeroen Proveniers]

> -----Original Message-----
> From: Martin Czech [mailto:czech at Micronas.Com]
> Sent: Friday, August 04, 2000 9:20 AM
> To: J.Proveniers at orga.nl
> Cc: synth-diy at node12b53.a2000.nl
> Subject: Re: Feedback in FM synthesis
> 
> 
> Yes, output back to input. Thsi should be 
> equivalent to a inifinite chain of operators,
> all with the same settings. So the output is harmonic
> with all harmonics present, that is likely to be
> sawish.
> 
> You did not give the actual formulas, so it is hard
> to tell why things do not work.
> 
> Is the sample rate high enough?
> Feedback causes a lot of high frequency energy, this
> causes alias problems. Lots of feedback will finaly give noise.
> 
> FM synths therefore run
> at pretty high sample rates 60kHz +.
> But it is not very likely that this is your
> problem.

I quickly tried this a minute ago

for (phase=0;phase<360;phase++)
 {
 out=sin((phase+out)/180.0*PI);
 
 ...some graphing here...
 }


and that indeed works as I expect. Probably I should take a look closer look
to my implementation.

JJ
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