spectrum of PWM

[Jim Patchell]

    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.