Feedback in FM synthesis

[Jeroen Proveniers]

> -----Original Message-----
> From: Martin Czech [mailto:czech at Micronas.Com]
> Sent: Tuesday, August 08, 2000 9:30 AM
> To: don at till.com
> Cc: synth-diy at node12b53.a2000.nl
> Subject: Re: Feedback in FM synthesis
> 
> 
> :::John Chowning's original patent is FM.  US patent 4,018,121:
> :::http://www.patents.ibm.com/details?pn=US04018121__
> 
> In this patent I see the formula:
>  
> e=A*sin(wc*t+I*sin(wm*t)) (page 19 of 32, second row, line 7 or so)
> 
> I think I is intended as modulation parameter independend from wm.
> If this is the case, this formula describes PM and not FM.
> 
> For FM it should be:
> 
> e=A*sin(wc*t+I/wm*sin(wm*t)) 

and what about this:

(I implemented it this way)

e=Ac*sin((Fc+sin(Fm*t)*Am)*t)

One thing I noticed is that it creates very dull sounds, not bright. There
are no sharp peaks.

JJ
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