spectrum of PWM

[Grant Richter]

Perhaps this has some info

http://www.musicsynthesizer.com/Circuitry/probability.htm

> From: Jim Patchell <patchell at silcom.com>
> Organization: Jim Patchell's Electronic Music
> Reply-To: owner-synth-diy at node12b53.a2000.nl
> Date: Mon, 04 Dec 2000 08:57:43 -0800
> To: DIY <synth-diy at node12b53.a2000.nl>
> Subject: Re: spectrum of PWM
> 
> Let me up the ante on this one.  I would also like to know what the
> phase relationship of the harmonics are as well.  I am assuming that the
> harmonics change phase as you change the PW becasue that is what it
> sounds like (but, I could be wrong!).
> 
> -Jim
> 
> Haible Juergen wrote:
> 
>> Does anybody have a formula for the spectrum of a PWM
>> signal ?
>> 
>> (I'm aware there are spectra published for certain fixed
>> pulse widths, but that's not what I'm after.)
>> 
>> So, is there a closed expression for the PWM spectrum
>> with Triangle carrier and Sine modulator, with modulator
>> fequencies up to carrier frequency ?
>> 
>> To make things easier, let's assume initial PW = 50%
>> and modulator amplitude < carrier amplitude.
>> 
>> JH.
> 
> 
>